The Origins Podcast with Lawrence Krauss - From Quarks to Galaxies: A tour through the forefront of modern physics with Frank Wilczek

Episode Date: April 23, 2024

I have had the privilege of working closely with Frank Wilczek for over 40 years, on and off, and we have written perhaps a dozen scientific papers together over that time. Our collaborations together were always a source of joy, and often of wonder, and I am pleased to say that a number of them had significant impact on our fields of study. While I have had the privilege of working with many talented scientists during my career, Frank is unique. He is one of the most broadly read, deep, and creative scientists I have known. To first approximation, he has read everything in science, and one of the characteristics of our own collaborations that has been so much fun is entering an entirely new field of study and learning how much is known about it, and how that knowledge might be used in new contexts. Frank is likely the most significant theoretical physicist of my generation, and along with Ed Witten, perhaps the intellectually most gifted. That he won the Nobel Prize for work performed as a graduate student with David Gross to develop the theory of one of the four known forces in nature is notable, but it just scratches the surface of his interests and accomplishments. While Frank and I have appeared onstage together on numerous occasions, I was waiting for the opportunity to sit down with him for an extended period to discuss his life in science, and the areas of study that reflect the most significant developments of recent times, and the outstanding challenges in our field. It was a pleasure to be able to do so for this podcast. I hope you enjoy it as much as I did, and that it inspires your interest in the world around us. As always, an ad-free video version of this podcast is also available to paid Critical Mass subscribers. Your subscriptions support the non-profit Origins Project Foundation, which produces the podcast. The audio version is available free on the Critical Mass site and on all podcast sites, and the video version will also be available on the Origins Project Youtube channel as well. Get full access to Critical Mass at lawrencekrauss.substack.com/subscribe

Hi, and welcome to the Origins Podcast. I'm your host Lawrence Krause. I've had the pleasure and privilege of working with my friend and colleague, Nobel Prize-winning physicist Frank Wilczek, for almost 40 years on a wide variety of projects. I think we've written a dozen papers together that I like to think have had a significant impact on our respective fields. During that time, I've gotten to know Frank as one of truly the most remarkable intellects

I know, having read a wide variety of areas of science, he's incredibly well read, incredibly creative. And I think certainly one of the dominant theoretical physicists of my own generation. I've wanted to have a deep dive with Frank about his own career in science, his perspectives of physics more generally for some time. And I'm glad we finally got to sit down and do that in the podcast you're about to hear. You can listen to it or watch it, in fact, add free on our Critical Mass Substack site. If you subscribe to that site, it supports the nonprofit Origins Project Foundation

that produces this podcast, and I hope you'll consider supporting the foundation. You can listen to it or watch it as well on our YouTube channel and subscribe to that channel or listen to it on any podcast site you can go to when you enjoy listening to a podcast song. No matter how you listen to it or watch it,

I think you'll be entertained and inspired by listening to Frank, and I hope you enjoyed as much as I did. With no further ado, Frank, Willcheck. Well, Frank, it is a delight to finally have you on the podcast. It's so good to see you. I hope you're doing well. I'm doing very well. I'm happy to be here.

It's been a moment. Well, good. Well, it's, I'm here, and we're about to have, it looks at my studio, it follows me around, but you can see outside my place here. It's lovely. the calm before the storm because I'm told we're going to have 20 inches of snow in the next day, but we'll see. Oh.

And that'll be pretty. You know, it'll be beautiful as long as you don't travel. Yeah. But it's, it was, we had snow. Last week, I was crushed her and skiing, and now it's, it's melted. So it's, it's, uh, it's nice, but a fake spring. Anyway, it's nice. Maybe I'll come visit here someday.

It's, this is a, this, this is an interesting podcast for me to do because I don't think I've known anyone as long as I've known you that I may have done the podcast with or maybe maybe a little longer one or two people but but I was just counting it so it's been 40 years for my goodness yeah yeah it's well wow and and I have to say it's been a remarkable experience uh as a friend and colleague and obviously one of the most remarkable intellects I've I've gotten to know as well as people. And so, so I want to, there's a lot I want to talk about. I'm hoping to learn something, new things about you as well. I also noticed I checked, I was trying to figure it out. I went to inspire, we've written 11 papers together. And, uh, which I, and, um, yeah, and some of them are

very good. Yeah. Some of them are very good. I'm very proud of a number of them. And we'll probably go on some of the physics that might be related to some of them, although I won't, I'll try not to focus on me, but you. But so I want to, I want to use this as a chance, obviously, for people to learn more about you and your work, but also for me to learn some better. And as you may or may not know, the origins podcast is aptly named because I like to learn about people's origins, how they got to where they're, how they got to where they're going and where they are and the roots they took that may be useful if people learn about.

It's certainly fascinating for me. Now, I want to go therefore back to your childhood. I know a little bit. You and I have talked about this in the past. I want to talk about your parents who I never really, I never got a chance to meet, which sad me. I don't think I ever met your father. Although I have a big memory somewhere, but maybe not.

Your father was influential to you in a sense he was self-taught. And he was a permanent. So did he go to college or no? He didn't even finish high school. the first go-round, but then he got, you know, after having a job and getting married and all that stuff, he returned to school, got his equivalence degree and took some college also. So, you know, so I don't think he got, well, I know he didn't get a degree from college, but he did, he did take a few classes and was able that were directed towards his career. So filling in the gaps, learning calculus

and basic physics that had to do with his work as an electronics and technician and engineer. He was a repairman or a technician? Did he? Well, he started as a repairman, but over the years, he got pretty proficient and was, I think, fair to say, he was a practicing engineer. Did he work in his own? Did he work in a company? Oh, he worked in a series of companies, right? So some of the early companies that pioneered printed circuits, actually. Oh, wow. Okay. Now, I seem to remember you telling me at one point that you both learned capitalists together at the same time. Is that true or no? Yes, that's basically true. Yes. I looked at the books he was taking he was bringing home and uh was you help him with it

he didn't no he didn't he didn't appreciate that that he didn't help me either okay well that's all right he let me look at the books yeah that's good well and i asked no a few times he did help. I asked him about some problems I was stuck on, and he was able to guide me. Oh, that's great. So I knew that, and I knew that that had, I mean, from our, from knowing you in our discussion before, that that obviously had an influence on you. But did, I assume your interest in science and math happened earlier. Oh, first begin. I don't know when it began. It's always been, it's always been, part of my makeup, I think. My very earliest memory is of sitting in our kitchen.

I think it was pre-verbal even, really, or, you know, a very primitive mastery of knowledge, but we had a percolator, a coffee percolator that had seven pieces, big pieces that take apart and put it back together. And I just did that over and over again. And I remember the feeling of mastery because you had to put them in the right sequence in order that they fit. And that was not easy for me to get a grip on. But then I did and I was so happy. And so I remember myself.

And it was like, in a way, it was to me the dawn of my consciousness. It was the first thing I remember. And suddenly I felt that there was a world out there. And I was an agent in the world that could affect it. So that was quite something. Yeah, that is interesting. I never heard that. That's fascinating.

Were your parents around? Were they encouraged? Do you remember if it was just you? I mean, obviously, you weren't in the kitchen alone if you were a little kid. I think my grandmother was there. We lived upstairs and my grandparents lived. All this parents lived downstairs, but I would often wander downstairs.

Your grandparents were immigrants, right? Their first language was in English? Yes. My father's side is from Poland. Poland, sorry. What's now, it's now in Poland. Part of, part of my grandmother's birthplace was part of the Austro-Hungarian Empire at the time. It was all. And my mother's side of the family is from Italy. From Italy? Oh, not just a region. Avalino. In Avalino in a small town outside. Avolino.

Lino is notable for being the birthplace of Tony Sopranos. Oh, okay. Which I remember he used to love the Sopranos, too. I remember he used to watch it. Yeah. Okay. Anyway, well, that's it. Now, did they speak English?

I mean, obviously they spoke English. Oh, yes. Yes, they spoke English, although on the Italian side of the family, not great English. It was heavily accented. And only, you know, only, marginally grammatical, but they did speak English in a comprehensible way. And my father's side of the family spoke quite well. You didn't learn any, they did any Italian. No, no. At home, we only spoke

English. Okay, it's just one. I'm not sure whether my parents knew each other's. A parent's language. One native language once removed. I don't. I don't think they did, actually. So necessarily they communicated in English. But they were, they were, you know, they were certainly Americans. They were not. Yeah, but did they speak, did they speak their respective language to their own parents or no. They didn't speak Polish or Italian?

Just wondering. A little bit, a little bit. But I think, well, this is pretty hazy in my memory. But my impression is that when I was really young, they did more, but over the years less and less. Did your grandparents have any other influence? I wasn't going to ask by your grandparents, but since they lived close by,

they probably weren't educated. Did your grandmother have an influence? Yeah, my, well, my, well, they were influenced in the sense that they were the rock on which the family was built. And we would see them for frequently and felt, felt very rooted there. I think that meant a lot, especially to my mother.

The only grandparent that I really had a relationship with, I felt that influenced me, was my paternal grandmother, who was educated. She was trained to be a teacher in Poland. Or Austro-Hungarian Empire. But her trajectory was interrupted by World War I and that she emigrated to the United States and and none of her training was useful so she just took odd jobs and think of that.

So but she, she loved to play cards and games and I really enjoyed her. Yeah. Oh, that's wonderful. Well, I want, I'm again, Nirm, one of my early, she was very encouraging. She was, she was, she, Yeah, she was the only really interested in school. Well, I was going to say, well, I'm jumping around. I was thinking about books as well. I know you have a lot of books as I do, but I know you have a great love of books. And I think that's an important thing for young people. And I wondered, who encouraged the reading?

Did your grandmother encourage that at all? Or no, or was your mother or father? It was mainly my mother and father. My paternal grandmother, one of her, charms is that she approved of everything I did. She was just, oh, Frankie can read so much. It's that great. And he's doing well in school. Isn't that great? That's important. You know, but I, yeah. So she would, but I, well, I, I think I blurted out she was, she would be enthusiastic about anything I did. And that's probably true, but I think she was especially enthusiastic.

about academic pursuits because that's where she came from. Yeah, she came from it. I didn't know if you had it. That's interesting. I didn't think you either of your parents had any of your academic background, but having a grandmother who did was interesting. The other thing that you said that struck a chord is one of the first things I remember about you once we became friends.

And I got to know your family and spend time with you is love of puzzles and games. and which I think is wonderful. I love that you loved to play games with your kids, which to me was something that meant a lot, and I wanted to emulate when I had kids. But did that, so that, you know, that arose initially out of your grandmother, that love of puzzles and games, you think?

No, it was just, well, I mean, she certainly didn't discourage it, but at all. But in fact, she loved, she also, I it may have come from her in the sense of genetics. I didn't need to be encouraged. It was just something I'd love to do always, because card game. She loved card games especially. Someday I'll show you my magic tricks, by the way.

I became a good proficient. But anyway, okay, what about your mother? What was her background and what did she do? I don't know so much about her. Well, she was a traditional woman of the era, kind of a very family-oriented, what you call a housewife, but she had done very well in school, but just, but after working briefly at a bank as a teller or something, she just got married and that was her. Did she graduate high school? Did she? She did graduate high school, right.

And she went to Catholic schools, which she hated. She hated the nuns were apparent, you know, the nuns were difficult people. I assume that was one of the reasons you went to a public school. Well, yeah, I mean, the public schools were good and there was no need to do anything else. And, yeah, I'm not, I don't, I think my mother, would have been vehemently opposed to my going to a Catholic school after her experience. And my father, too, because my father, I think, was very suspicious of religion, I would say. I don't want to dwell on religion, but did you, was it at all religious huts?

Do you go to church ever or maybe just Christmas or? Yes. Yes, I went to church every week and catechism classes. when up till the time when I was on the on the borderlands of teenagedoms. So and I took it very, very seriously. And in the Catholic tradition, there are books and literature to study. There's lots of structure and things to learn. And I was very into it.

You know, that another puzzle, I won a prize once, which was sort of like the percolator. It was an all, there's a plastic altar with different pieces that you could take apart and put together. I like that too, but, but the, yeah, I took it very seriously and in, I even thought to myself that I might want to become a priest, that that sort of life of contemplation.

Yeah, sort of a monk like that appeal to me and dedication to some higher calling. But as part of the initiation into consideration into consideration, Catholicism. Well, there's baptism, but that is now for babies, infants who don't really understand, of course. And then there's a confirmation process, which comes when you're in your early teens, typically, in my case. And like the bar mitzvah, but a Catholic version of it. It's like a barme, exactly. It's very parallel to bar mitzvah. And the in preparation for that, it's a sacrament. In preparation for that, there was a retreat where it was properly drilled in what the faith meant. It was really, it was an intense, a very intensified version of the catechism class.

says that way. It took once a week. And that's when my religiosity got most intense because it was a very intense exposure to the faith. And if you took it seriously, it's, it's a very big deal. I mean, Do you want to go and be eternally punished or do you want to live in paradise? But at that time, meanwhile, in parallel, I was learning about science. And being confronted with these two very different accounts of the way the world works, was a kind of shattering experience. Take it really seriously and then step back. And you sort of get to assess it more at a distance and reflectively,

with not immersed in this camp. I went sort of from the height of my religiosity to a complete collapse because it was a crisis. I realized that I couldn't reconcile these things. And, you know, I was very well aware of the apologetics and kind of, you know, the dodges. But they didn't really, I didn't find them at all convincing. And what bothered me is not even so much the contradictions as just the lack of imagination and lack of any indication that this writings regarded as sacred were anything more than people who didn't know very much about. the world,

trying to account for it in terms of the concepts they knew. There was no mention of atoms, no mention of dinosaurs, the big universe out there. No, no, sorry, no mention of dinosaurs. You know, a lot. Yeah, there's just, it's just, it was this very parochial thing.

Yeah. An obsession about Middle Eastern real estate and, and rules about, sexuality and ritual that just yeah when you put that beside the scientific account of the world and marvelous surprising things that that that that it opens up and and that supports critical thinking and testing so it's not you know you don't you're not apologizing you're not getting to a preordained place you're trying to

do your best to really understand things in an honest way. And even when you think you've reached an understanding, you keep challenging it. That was a very different point of view, and one which I found much more impressive, much more congenial, and it just soured me on the other approach. It's a beautiful, actually, discussion, description of the contrast between the sort of scientific process and at least the formal religious. just one. But let me, let me ask you also, was it, was that an existential pressure?

Did you get depressed or feel guilty that some, or was it just easy to dispense with? And some, once you realize that you couldn't accept it. I asked this, well, it wasn't, it wasn't, I have to remember back in that time. It's been a, it's been a while. As I remember what were, no, I was, I was, I was very comfortable with. with the decision, after, you know, maybe a few hours, maybe a few days of real crisis. This is, this is just like the devil leaning over your shoulder and telling you this stop and you're going to, you're going to regret it and for a long, long time. I got over that. And really what took me longer to come to terms with was how to break it to my family.

I was wondering what exactly was about. And for my parents, I don't think it was either surprising or upsetting. They were not really themselves believers in a sense. They were cultural participants in a community. And really, they were, I think, mostly in it for my benefit and my brother's benefit so that we could be part of this community. And of course, my grandparents, especially my mother's side, for them it was much more serious. They came from the old world and where the whole culture was built around the church. So for them, I don't think the dogmas were that important, but the identity was very important.

So I decided that I would, you know, I was very comfortable with my own decision. But I wouldn't, I wouldn't advertise to them that I would, that I was, that I was, that I was, no longer a believer. And it continued as appropriate to go to Mass occasionally, not every week anymore, but maybe at Easter time. Sure, sure. And on special occasions. Special holidays like I did was a Jew at some sense. I stopped at my afternoon. But the, well, I want to ask you a more question because our,

on the whole, was it a net positive because it encouraged thinking and reading and speculating and and deep reflection or a negative in the sense that I have a lot of friends and actually family who Catholic, brought up Catholic and a number of them are scarred from the, I mean, from the sense of guilt that it builds up, you know, that you could. And so was it, so do you have any feelings one way or Are there positive or negative? For me, it was very positive. Overwhelmingly positive, I think. Because it occurred your thinking or what?

Yes. Yes. And it encouraged me to think that there are hidden meanings to the world that you're by thinking about it. And it, you know, that going through this crisis was, was a strengthening experience. There's an example of hormesis, whatever, it doesn't kill you, makes you stronger.

Yeah, well, no, and it's being able to change ideas radically when it's appropriate. And also to just be able to imagine changing, even if you don't change, to have that kind of tool, I think was very important. So for me it was very positive, but I could understand how for other people and other circumstances,

it might be much more difficult than much might leave lasting. Well, it's hard to sometimes overcome things that you don't learn with your head, but your gut kind of, you know, when you're a kid and it's hard to give up and lay out. And also, I think if my parents had been more deeply embedded in the community

and if if I was more deeply embedded in the community, it could have gotten very uncomfortable. Yeah, it wasn't. But I was, you know, I was, again, I was happy to maintain appearances. That was not sure. Well, yeah, you're not naturally, yeah, you're a, from my experience, yeah,

anyway, you're not the kind to provoke in personal situations. It's, yeah, and that's a good thing. The experience you had, though, it hit me because I've said, I've been recorded a saying, but it's true. I believe that one thing I hope for every student at university is that they have some idea that seems to be central to their being proved to be wrong, because that's a foundational experience. It's a important experience, and certainly it's a good preparation for being a scientist, but

more generally in life that to realize that that you can be wrong about fundamental things opens your mind up yes and also that you can change yeah that you can change exactly you can change your mind and and you don't always have to feel a bit you know yeah i and it's one of the things that um you know i'm more worried about college students nowadays experiencing that having i being confronted about things that that they may be uncomfortable with ideas they might be and comfort with it, with force them a changing mind. So it's part of education. Yeah.

Well, the first thing is establishing a mind with this barrage of information from all dimension, for all direction. I worry that people don't have a foundational core. That's an interesting point. Because there's so much barrage now that we didn't have the internet. We didn't have, we were, we were, we were, barrage by misinformation, but in a very directed way. It was a finite amount.

And it really made a difference, you know, because you had sources you could trust in sources and you couldn't. But yeah, the last before I move on, and this has been actually, it's fascinating for me at least, but the love of books, where are a lot of books in your house or? No, there are very few books in our house. but we lived pretty close to the public library and my father encouraged me to buy books. He would contribute 50%

for books that he approved of. So those were basically technical books, which is what I want. it anyway. And there was a very good bookstore, not far from our house. We had to take the car. It was a big bookstore with lots of Dover books. Oh, yeah. The Dover publishers. Sure. All the great. A lot of scientific classics. And so I educated myself quite a lot on Dover books. They're classics. Classics. And cheap, too, and not too expensive, which is another good thing.

Right. I used to be very cheap. Well, okay, I'm maybe in constant dollars. Yeah, it's still cheap, but yeah. Yeah, it used to be like three or four or five dollars. I mean, something like that. And it was, yeah, they were accessible. And that's great that he encouraged that. But also, I went to very good schools in retrospect.

Yeah, in retrospect. Yeah, I know your high school was a great, good public school. I assume your primary school was a good primary school. Yes, that we lived in a kind of the outskirts. of New York City. So we were in the city limits, but barely. And at that time, it was a, it was an excellent environment

to learn. The kids around me were basically had similar profiles from the second or the second generation or so and strivers. You know, every, all, they all wanted to do better than their parents.

And the teachers were very good and encouraging. You know, so that it was. Well, you hit the question. It was very well organized also. That's the public school at that time. And big. So it was big. Is that a good thing?

Yeah, it was a very good thing because it enabled classes to be given at different levels and to cover a wide spectrum. Wow. Okay. But you hit on one thing that I was just going to pick up on was other influences. Your brother is older than you, by the way? No, he's younger. Younger.

He's passed away a few years ago. Yeah, I remember that. But he's younger. Okay. So you were the big brother. So you know more of an... He's significantly younger, like five and a half years. So we were not really in sync.

Yeah. But you were more of an influence on him than vice versa. I was thinking about me. I think that's fair to say. Yeah. But what about peers? More influenced by his friends than by meals. Well, it happens for most kids, I think.

And now let's talk about friends. So it was neat that you surrounded, one of the things you mentioned, you're surrounded by people who all wanted to do better than their parents. So you were surrounded by strivers or motivators sometimes. And well, even more their parents wanted them to do better than their parents. I think it was a traditional characteristic of our era.

We're both the same. than you're three years older than me. But what about peers? Did you have, like, did, you know, I remember. Yeah. I had a few friends who shared that. Yeah, I had some very close friends all alone, a small number. They changed over time.

But it was, I always had a nucleus of two or three friends through grade school and what's now called middle school. junior I had that. They were, so they were two categories. One was kids from the neighborhood. So they were, you know, there were, we lived in a small apartment that have, in a village, a village of a small apartment.

So there were lots of kids. And I spent probably most of my time outdoors every day playing with kids. Yeah. And so though, and that was, very influential in forming my identity, I would say, and my physical health and so, but not so much intellectually. But then when the classes got more specialized and the schools got bigger, I made friends mostly in school. those were people who were intellectually talented and ambitious and influence in that way. We taught each other and interacted and competed.

Speaking of competition in that regard, I was just occurred to me to ask it. So did you have friends who were better than you in some things? Or when you competed in either math or? Well, there were some people who were better than me in certain. Yeah, I had some weaknesses, not in math, but in languages, partly that I wasn't very interested in, but I was also blown away by easily some people advanced in foreign languages. Music.

Well, I was going to, you're anticipating me. I was going to get to music. I know how musically talented you. I would have, I love music and I loved making music, but there were people much more talented than me that I learned. And also in chess, somewhat surprisingly to myself, I would have thought I'd be really great at chess, but I'm pretty mediocre. Yeah, but, so isolated things. overall I was and there was certainly other students who took the classes much more seriously.

I, you know, in the business of getting good grades. I wasn't quite at the top of my high school class. I think I, if I remember correctly, 13th or 14th out of 1,000 and something. Now, partly that was because I had skipped grades. but but but but they were so there were there were people who you know had a little bit higher grades mostly because of the languages yeah but yeah but no i i i uh i i was i did very well and oh i know i know you did very well i just was like things like the science talent search yeah we'll get there we get regions exams and things like that yeah well i know yeah i yeah i

I was just thinking about, do you have any of your friends, I've, weird for me, again, if I think about the people I know from high school, actually all turned, the only people I still know, it turned out to be scientists and in many ways academics. Any of your friends go on to be scientists or engineers or academic? Oh, yeah. Well, doctors, they're doctors, and a very distinguished doctor.

The person in the class before, and yeah, and so they were, quite a few eminent academics for a school of my size. I mean, for a single school, it's amazing if you look up high school, if you look up Martin Van Buren and the list of distinguished... I did. I'm not. You'll see quite... It's pretty eye-popping.

So we have another Nobel Prize winner, Alvin Roth, in economics. If you count economics as a Nobel Prize. But then we, Mario Savio, who was, according to my teachers, was at least as brilliant as me, became leader of the free speech movement at Berkeley and was kind of a tragic case. He was very gifted. And very, he was very, politically committed and people admired him but the teachers admired him for that.

But at the end of the day, he couldn't sort of balance these things and wound up keeping bar and Berkeley or something. Yeah, there's a bunch of. We also had famous actors and actresses. These two actors, I've noticed, yeah, when I did my research. Yeah. Well, okay, so you were trying, so these, I mean, I think people get both in high school and university. I tell kids often, you know, go to a school.

It doesn't matter. You can get a good education at any university, but one of the things you might want to do is surround yourself with peers who are interested. And, you know, because that is influence. And certainly it was a factor in high school. But one of the things, before we get to the university, and we will get through all this in the first hour, and then we'll get to the physics. But I think it's actually, I think this is fascinating to learn about for people and the background.

One thing I didn't know, and I found it in Wikipedia, which I am partly suspicious of, but was, it said your parents found out you were exceptional by an IQ test. So I knew that, you know, you obviously did extremely well, and we'll get there at a young age. But I didn't realize it was sort of that either you recognized, other than doing very well in school,

that somehow you might have a very good intellect in that sense. So did that impact? So apparently there was an IQ test, and did that affect your parents and what they want or expect? It had a big effect, I think. The reason that we got to know, well, IQ tests were administered in the school, Yeah, sure.

Same good. And the teachers were recommending to my parents that they send me to a special school. So that that's the reason why we got to know about this. And I think that had a big effect on my parents. to get to they we didn't of course we didn't go to the didn't take them up on that

was thank God thank goodness we didn't actually but but the but I think they I could see that they looked at me in a different way from then on they

didn't give me so much grief well they no they they talk to me more as an adult I mean more with mature way expecting more for me. Yeah, respecting more for me and also yeah, so instead of

punishing me by discipline, you know, physical discipline which was still looking at that time. Yeah. Or by we, removing some privileges, they would just try to shame me. which worked very well.

Yeah, it's hard to articulate exactly the change. It was a very noticeable change in the atmosphere around the house. And also I noticed the teachers. They all knew about this. And so they kind of made allowances for me. They, they, if I wasn't paying attention, they said, well, you know, that's Frank. Oh, wow, that's a nice.

In some classes, they just say, you know, go to the back room. Go to the back of the room. Don't make trouble. But here, you can read this on your own. Right. It's nice to be, you know, a lot of this is fulfilling expectations or not having poor one. So it's nice to get a, it's nice to have that kind of expectation.

That's interesting. That's intriguing. I, yeah. They cut me a bit of slack. Yeah, that's wonderful. It never happened in my school. In my school, the teacher, we were administered IQ tests, but not, I don't think it was told what they were.

And then one teacher felt I was just not working hard enough or doing well and said, and basically revealed to me the result of IQ test. And more as a punishment saying, look, you, you know, you should be, you know, anyway, but that's nice. Well, look, I, you did have a, you went to this, you went to this great high school, Martin Van Gogher High School, which was a great, and the state has a history of I'm really good. At the time it was a great school, right? It's sailing. Of course, it's happened a lot of back now. Yeah, the U.S. has a history of really good suburban high schools. When I moved to Cleveland's Shaker Heights High School as another example. I remember when I taught of you a lot,

a lot of students from there. Good suburban high schools, lots of opportunities, lots, as you say, different classes. You had a, you did mention a physics teacher. Were your best, was that your most influential teacher in high school? No. Physics teacher. No, my most influential teacher was probably my math teacher, Mr. Ewan, who just

passed away recently. He was very challenging. He also he was very fond of puzzles and bridge. And very charismatic with the kids. That's great for a massive class of kids.

And so that he was very, and the other one who was influential, maybe it's hard to compare, maybe equally influential. I mean, probably the most influential, really, if you objectively evaluated it were elementary school teachers. Yeah. Yeah. Really. They are the ones who really, yeah. The deeper directions. Yeah. But, you know, at a more technical level, I had for a brief period, a teacher named Mr. Gottlieb was actually

became a pretty distinguished figure within the world of pedagogy in science at that level. So I had him in a physics class, and he also like to give sort of challenging problems,

but when I solved one, when I solved them, he said, you're too advanced for this class. And I went to a different class that was for, you know, the next, the kind of next level, which I really wasn't ready for. But so it was kind of going into the deep end of the pool. Yeah. But, but, and the teacher wasn't as good, frankly. Yeah. So he had a kind of influence too. And I kept in touch with him.

Is he the one who encouraged you to go to the Westinghouse Science Talent Search? no that was the second one well both of them both yeah both so now i want to ask about that because i have a number of colleagues who've done well on that over there friends and colleagues who i know i you know i was grew up in canada we didn't do that kind of stuff but but uh you know i've officiated i've become a judge at one year or two years in that and and um in in it's that and its successors um i make i i have mixed feelings about science content so I wanted to ask you about your experience there

and what you think oh I think it was very good for me and and it it was well first of all you know it's always nice to win prizes

and I mean there's a series of local regional and national right you have to win some things to get into that at that time I don't know if it's still quite the same. I should know, but there was a written exam and there was a project and there, I think there were evaluations from teachers and so a lot went into it. And then they announced 40 finalists who made the trip to Washington. So this was not a science fair. This was

a science fair. I have very much experience about science talent search. Yeah. Yeah. So it's a very different So we flew to Washington, which was a great experience. It was really my first experience outside the family. Well, not quite. No, my first experience outside the family was going to a summer math camp the summer before, which was actually where I did the project. But it was a very inspiring experience to go to Washington. and to take an airplane.

It's kind of on my own and meet other students who were from all over the country with interests in science and some kind of demonstrated aptitude for it. And we're very interested to talk about it. And I met Glenn Seaborg at that time. It was a Nobel Prize winner. It was just in awe of this. And but also just to interact with the students and also the other judges,

besides Seaborg, and suddenly to be taken seriously, not as a student, but as someone who might actually contribute. That sort of planted a seed. I didn't fully realize it at the time, But, and then I won fourth prize. That was very exciting. And that, I think, helped me to, well, it gave me a lot of confidence.

And I think it also helped me to get into a special program at the University of Chicago. I was going to say, did it mail up and doors for you? Did it also give you scholarship money for the university? They gave me scholarship money, which was a little more. than the Westinghouse prize, but then they deducted the prize and the prize went up. Oh, no, no, no, I'm saying,

no, I expected the university gave a scholarship, but the Westinghouse gave you a scholar, the Westinghouse prize, $4,000. Yeah, which at the time would have been a lot of, it was very meaningful to my family, very meaningful. Yeah, made a difference for you. Would you have been able to go to a school,

a private school, like University of Chicago without it or financially? Do you know, maybe even? Probably. You know, my parents were ready to sacrifice for that, and they could have sacrificed a little bit more, I guess, if necessary. And maybe the university would have come up with fuller support as it was. I don't have to say, I don't really remember the details of this. But I think I had a full scholarship, but that did not cover, it covered tuition. It didn't cover the business. just yeah. Okay, so you, and it's worth mentioning that what the science, sound search project was math. You've gone to a math and you, you, you got one of not prize for your math work. It was a group theory, as I recall.

Yeah. And, um, and then you, you did a math degree at University of Chicago. Is that right? Yes, your math. So math was your, with, initially, you're, you're, you're clear, interest. I mean, simple. Yes. Well, yes and no. I mean, yes, it was. And I learned a lot of myth, but I didn't aspire to be a pure mathematician for two reasons. I mean, first of all, I found the applications of mathematics more fascinating and kind of magical. than pure in pure mathematics i didn't know why people wanted to do one thing rather than another you know why is it why is it important to calculate the higher homotopic groups of spheres as opposed to doing the cobordism of or or uh proving things about uh number theory you can go

in any direction uh i so and i think partly because of that but not entirely because of that. I didn't have the talent for pure mathematics to really thrive in it the way I thought I could thrive in other directions. To really be good at it, you have to have superhuman talent and or, depending on how super it is, and or tremendous dedication and kind of single-mindedness. It's tough. You have to actually prove things and and modern mathematics you have to learn a lot if you want to get to the frontiers and it's very specialized and yeah so yeah it wasn't it wasn't it wasn't the experience you know that my book on Feynman but but you know i mean i remember fineman was thinking about doing math

and and and asked what what he could do and they said well you could be an actuarial for well that's not what i want to do i guess i don't want to do math so he chanely chose physics but he thought that for him, that was the bad advice. He thought about what a mathematician would be able to do. So anyway, I loved and do love the kind of symbol manipulation and logical thing that go with mathematics and the building of structures, accumulation of technique. One of these things that's marvelous. But I really had in mind I wanted to use it for something.

Well, this is interesting to me, Frank, because you did a degree. Well, we'll get, I don't want to jump ahead to graduate school, but you did, it is interesting me, you chose to go to grad school math. So you, which is, and generally the trajectory of that would be to become a mathematician. Yeah. At least considered that as a reasonable trajectory early on. Well, yes, and I was kind of went to Princeton under false pretenses in retrospect. I didn't want, I really didn't want to do pure math, but I didn't know what I wanted to do.

Oh, I see. And I wasn't prepared for anything else. So it was kind of the path of least resistance, frankly. And the things I was seriously considering were, well, I was open to anything. But the things I was seriously considering in the sense of doing the necessary foundational work to be able to make a choice were physics. I was always interested in kind of mathematical logic, what would now be called computer science. And related to that in my mind, Neurobiology, trying to understand how minds work mathematically.

So those were the directions that I really wanted to explore. Even when I first went to college, that's pretty sure. Things I wanted to explore. And if I had known more about chemistry, I might want to learn chemistry. Chemistry would have been a very good thing, but that wasn't on the radar screen. And I thought of chemistry as, you know, chemistry set when you mix things up and actually had an explosion with one of my early chemistry sets. And then I was banned from my parents would absolutely not let me do chemistry. Not an unfamiliar experience for some of us.

Chemistry sense were easily accessible. But, okay, I jumped ahead to Princeton. And we'll get back there. But there's two things I want to ask. Why did you choose University of Chicago? Or was it the scholarship? It was really the scholarship. And they're, you know, it also, you know, that was a good, very good school.

Yeah, it's good school. I know. But there were probably a bunch of good schools. Yeah, they were, but they offered a scholarship in a very special program called University Scholars. Yes. Which was associated with great freedom. And I'm not sure this went into my,

thought processes of the time but what I when I got there I found out that this was an added feature I guess which was that when you when you get I probably knew about this but when you get there you you would take a series of exams to see at what level you should start and basically I could start as a soft so that was that was advantageous maybe more freedom I could I thought, was it the Great Books program part of that at that time or the Chicago? No, not as such. There was some lingering influence of the Great Books program. There was something called History of Western Civilization, which was a required course, which was half your credits in the program I was in, was half your credits as a freshman.

And that was kind of great books. I mean, you know. Yeah, sure. It's clearly influenced by the great books program, but it was not explicitly that. And, you know, wasn't. So it, yeah, it wasn't focused on a small number of ancient texts that you went into in great depth. They were, that's, yeah.

Okay. Well, look, although it did emphasize primary. resources, but not, not to a maniacal extent. Well, I know I'd know you'd like to take a break in each hour for a few minutes. So before we get there, the last thing I want to ask, and then we could take it, if you want, we could take a little bit. I know your watch is going to be beating now. Yeah, but I've been aware of time.

But one thing I didn't ask you, and one thing intrigues me, you skipped two grades at school. So you went to college when you were 15 or 16, 15? I had just turned 16 when I had. Yeah, because your birthday's in May like mine, yeah. So you just turned 16. Was that, you know, there's pros and cons of taking kids who are smart and putting them and, you know, and moving them forward. There are pros and cons.

And, you know, there's social issues as well as intellectual ones. Yeah. For you, was that an issue when you look back that you might have, I mean, going to college when you're 16 is a, you know, is a challenge. Did you feel challenged in that way socially or otherwise? Well, looking back on it, I was socially backwards for sure. But I did have experience in making friends. Yeah, that's cool.

And I made some friends in college who really helped me. I had a girlfriend who worked at the poor lady. I think I really helped me to grow up. And I had to put up with, you know, a boyfriend who was still a child in many ways very childish. But that, it was very good, a good experience for me in preparing for life. So I had a lot of catching up to do socially, but my main focus was intellectual. Intellectual. But you didn't find that people noticed or cared that you were younger.

I didn't, what? You didn't find that people noticed or cared that you were younger or, pretty huge. No, I didn't look that. I mean, I was a little bit young. I wasn't super young. Yeah, but there was 16. 18 is that huge, I guess. Yeah. I mean, it is huge, but it's not. I wasn't prepubescent or anything. Yeah, yeah, not like 12 or 13. At least on the cusp of pre-pe period. Yeah, that's right. Okay, so, so you, yeah, so it was good for you, but you didn't find it a challenge and you were, you're happy you went at a young. No, I, I, you know, if I were a different kind of more socially oriented person,

I might have found it very uncomfortable to be a little bit of an oddball, but as it was, we were talking about math and physics and thinking about doing other things. At Chicago, you had a class from Peter Freund, if I'm right. Yes. And that was quite influential in your thinking. Yes. He taught him. This was my last semester at the University of Chicago.

When the campus was disrupted by demonstrations about the invasion of Cambodia. Oh, yes, 1972 or something? 1970. 70, 19. 17, 17. 72 was where, yeah. And basically, regular classes were suspended, but the, but some, some sort of went on. because of the enthusiasm of the teachers and the students.

And I don't remember the exact details, but it was a very special time. And he taught a course about symmetry and physics. Peter Freud. Yeah. And I just loved it because this was. kind of where the magic happens, where there was group, you know, group theory and group representations and SU3 and SU2 and rotations and also the discrete symmetries.

And he and then he talked about SU6, even at that time, which was kind of an extension of flavor SU3, and putting together spin and had flavor in modern language. And he was very enthusiastic. He was a very charismatic, energetic person who just loved the subject and conveyed that kind of enthusiasm. So the combination of the material and his present, and it was something I was ready for, I think, to see this confrontation of beautiful mathematics with physical reality.

And also the idea that it wasn't finished. Some of these things didn't quite work. You know, SU3 was approximate, the flavor is similar. SU6 was even more approximate. And yet it was useful. And, you know, the parity was broken, of course, and tiny. So this whole idea that you could have approximate symmeties, that there were still work to be done.

Somehow that was very appealing to me. Yeah. So at that time, you know, that kind of tipped the balance toward physics, although I didn't immediately take the plunge. I went to, I wasn't, you know, if I, what, because operationally it would have been very difficult. I didn't have the, I hadn't fulfilled the requirements to physics degree. I hadn't done any laboratory work. You had no laboratory work, okay.

Essentially not. That's right. That was one reason I majored in math because I, to avoid it. Me too, I didn't agree in math. Avoid it. Not because I didn't like it, although I suppose. sort of got frustrated sometimes because, you know, was using the student labs, the equipment wasn't always first rate,

and it didn't always work as advertised. But just it was very time-consuming. And I was so much that I felt I needed, I wanted to learn and I was having so much fun, doing more playful things that it just didn't, I didn't want to do that. And so it wasn't a practical possibility. And then, you know, once that course was over,

I kind of relaxed back into this state of uncertainty about different possible directions. But a seed had been planted in retrospect. In retrospect, yeah. You thought about it afterwards, and it certainly, it was certainly prescient when you look. look at the symmetry and physics and the work you let yeah no we the the that was a very fortunate thing to have learned at that time that's why I would love to have had such a course yeah um

a little bit but um and and then and then Princeton as you say was in some sense of plath at least vision before you talk about Princeton I have to admit I hadn't put two and two together so you were we were you in Chicago in 1968 I mean this was a I mean, did all, there was a, so did that, I mean, that was a dramatic time in the history of the United States. And as a young person, I mean, Chicago was an epicenter for political. Yes, it was. Revolution. Did that impact on?

I stayed away from politics. Not because I wasn't interested. And I was very sympathetic to the kind of leftist movement. movements at that time. And certainly the anti-war movement. In fact, I almost, you know, I was subject to the draft. I was totally exposed. Fortunately, I drew a very high number.

So the, but I realized that I could get in trouble that way. And I really didn't want to disappoint my parents is what it came down to. I didn't. And of course, I liked what I liked the studies and the kind of thing. So I kept my kept to that. But quite a few of my friends did not. Some of them became weathermen, you know, SDS. Sure, I was wondering about that.

And yes, I wasn't close to any of the face. famous weather people, but sort of one step removed. And some of them, quite a few of my friends got discipline, suspended for different amounts of time, for occupying the administration building, things like that. When you stayed away from them, never for the grace of thought. I kept the distance from that because I was very sensitive about, well, that the university had given me so much support. And then my parents were so invested in my success that, you know,

I didn't want to let people down. That's sweet. That's good because there, but for the race of God, you could have been Mario Savio. You could have been. Yes, exactly. Yeah, could have happened. Yeah. And, okay, and so let's move to Princeton. You, you, you, I think I may have asked you this once, but I don't remember to answer.

But so it was a path of least resistance. Was it also just also romantic because Einstein had been there or lived in Princeton? or why Princeton? Well, well, yes, actually. Einstein was a big hero in role model. Sure. I had romantic images, especially of the Institute of advanced study. That's where I wanted to be.

I wanted to be like hell. Yes. And just do research. That was my ideal life. Yeah, absolutely. And you've had a dimension. And it, you know, I knew it didn't necessarily have to be based in Princeton, but, you know, that was certainly a model for it. And so I was, you know, I was very pleased to go back to, to go there.

Did you apply to other schools? Yeah. Yeah. Did you get into them all? At graduate school, I think so. Yeah. I applied to, I didn't apply very many. I applied to Harvard and Princeton and Chicago, if I remember, and that's all. And you got, and you posed Princeton over Harvard because of the kind of monastic, or the romantic.

Yes. Well, also, you know, I took to academic advisors at, at Chicago, and they recommended that. Well, the Mathematics Department of Princeton is very good. Harvard had a damn good map the Bax Department, too. So it said, it did. So it wasn't, it wasn't, it wasn't, actually, I'd say it wasn't trivial to make that decision. But it wasn't, it wasn't completely arbitrary or just some romantic.

You got to fulfill your way. I don't dwell on that. We'll see later on. But of course, you did get to fulfill that, I'll agree, not just being at the Institute of Grand Study, but living in nine cents, which, yeah. So, yes.

Got checked. But you were there a year and a half before you switched to physics. And I want to, I don't, again, I think we've talked about this, but I'm intrigued on the switch. What caused it,

you know, it was bubbling in your mind, but were there things that happened at Princeton in math or in physics that encouraged you to make the transition? Yeah, well, I spent a year and a half kind of in the wilderness. I didn't really didn't know what I wanted to do. And it was becoming increasingly clear to me that I didn't want to do pure mathematics, although that was what I was expected to do.

Yeah. It also became clear to me that that's what they expected me to do. So it was a little problematic. But I persisted. I was quite worried because at that, that, point, I thought, oh, my gosh, after all this, I am going to disappoint my parents. I don't know. Here I am finally in the big leagues and I'm not not prepared for it, not mature.

And but I persisted. I didn't want to, I really was not comfortable with the prospect of becoming a pure mathematician and especially not with the prospect of becoming kind of a second rate pure mathematician. It just didn't appeal to me. That would have been that would have really been the path of least resistance. Yeah. But so I was looking around. I went to all kinds of seminars and colloquia in other departments. And the easiest one to go to was the physics building, the physics department, because it was right next door. And the, in the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, and it was, you know, very easy to just wander over there. And, uh, and I, uh, was very fortunate in that very exciting things.

were happening in physics at that time that used the kind of mathematics that I knew very well. And I met some very remarkable people. Although I didn't really form any kind of personal relationship, Ken Wilson was visiting. He gave lectures about his new, shiny new idea. normalization group. Yeah. And that was very interesting to learn about this. And his,

clearly, you know, people were, he was this strange, visionary, really inspiring. What's that? Role model. And then, of course, David Gross, who was a young, I mean, didn't necessarily seem super young to me at the time, but he, but it was clearly, you know, compared to other faculty members, was very young.

And very charismatic, very driven. And I've, and he was teaching the class in quantum field theory. So I sat in on that. There were only three students. So we got, it was very, only three students. That's interesting. Yeah. That's surprising.

For some reason, theoretical particle physics at that time was at a local minimum. There were very few students. In retrospect. Yeah, well, the period, past a period of flailing around, of not really, of a lot of confusion and not really no, you know, but, yeah. Yeah. But anyway, they, so I took that course and I really enjoyed it.

And got to, with David, we kind of did form a one-to-one person relationship. right away. And he kind of took me under his wing. He was also the director of graduate studies. Oh, so that made it easy. So I was wondering how easy the transition was. You had someone batting on you. That made it a lot easier. He could pull strings and make it possible. So very exciting things were happening, I learned, that from going to these seminars that from that there was their normalization group on the one hand and then there was the whole gauge theory thing this was the time when gauge theories that are now the standard model of the lecture week interactions were we're kind of maturing or not yeah i kind of this was the

time when they when they really uh got credible i mean you know that that that's and popular, but they weren't extremely well known at Princeton at all. I mean, so, you know, I think, even though I was a graduate student, I think, and not in physics, I think I played a significant role in sort of bringing Gates theory ideas to Princeton. Really? Yes. And David had been, David surely was taken with that. Yeah, David. David, well, David was, you know, hyper aware of the frontiers of physics, but he had come from a different direction. You know, he's a student of Jeffrey Chu and S-Matrix and the string theory at that time, but then converted to quantum field theory. And, yeah, he knew he certainly was very on, he's, you know, he's a very quick study, as you know, so.

So he was very aware of ideas of Gage. Well, as I remember it, I may be wrong about this, but I don't think he was so comfortable with large groups, where large means, you know, three, even S you're three. He certainly knew what it was at some level, but I think he was still a little uncomfortable with that. He was very reassured. let me put it this way he was very reassured that they had a student who really knew the group theory

stuff and yeah and anyway so so so though they were very it was clearly this this was a very promising thing for me to get into i felt that it was did he encourage you did he You know, saying as a student, did he encourage you to make, I mean, sometimes you need a person to make the transition. It's not so easy to jump department. So he encouraged you to say, you know, you really should be in physics instead of math or no. Did he ever say that to you? Yeah. Yeah.

Well, I mean, I don't mean, I'm pretty sure I suggested it at first, but he took it up with great enthusiasm. Yeah. You know, and didn't let me, he should, let me put it this way, he didn't let me backtrack. He's not the type. He made it very difficult for me to backtrack. Before we get on to the work itself, I'm intrigued, because you hadn't taken a lot of physics courses. Some departments would be bureaucratic and say,

well, if you're going to change, you have to, I think that I'm Princeton like MIT where I was at, these qualifying exams, so presumably you have to do them. So do you have to take the additional courses, any undergraduate courses, or any, or any, No, there were no course requirements. There were lap requirements, but they were kind of, they were waived. Oh, they were way.

They had a special thing for people coming from other departments. We could do that. And this was, I think, another example of David pulling strings. So we had to take the exams. And I really wasn't prepared for that. Yeah, what a thought. And there were two parts. There was prelims and the general exam.

I wanted to do them both right away. And so I sat for them. It must have been in the spring of 1972. And I passed the prelims. But I actually, the the generals were more kind of substantial problems that required more background. So this was a dramatic event. Some people will remember to this day.

I sat down and looked at the exam for a while and then closed the method and walked me. And so I did that the next full. Yeah, with, I still wasn't as prepared as I should have. You had to go through preparing. I mean, between the spring and the fall, you did some media work, presently. I did, yeah, I did. Well, I did what I felt was just enough to get by because I really wanted to get on with the research. It's fascinating.

It's interesting to me. I mean, I didn't realize it was similar. One of the things I enjoyed about being a PhD to do, my PhD, and my T is there were no course requirements. You just had to pass the exams. Yeah. And I'm, you know, and I took a gamble and did them after my first term. But, but it was a big, anyway, worked out. But then I didn't have a day. Anyway, then I fled around for a bunch of years after that. But, but that's great that you were able to do that without, without taking the courses, just, you know,

teaching yourself. Well, you know, I had, even in high school, I had, I had read the Feynman lectures as they came out. Okay. And, well, in retrospect, I clearly didn't understand. everything, but I thought I understood quite a lot from that. And I did. I mean, I had at least kind of general orientation of what physics was about. And I had taken a few courses, not just the Peter Freund course we talked about, but I took the freshman physics course, which at Chicago was quite advanced. Yeah. And I may have taken, I think I also took a classical mechanics course, but that was the other of these courses that got disrupted. Yeah.

You take an electromagnetism course as an undergrad? No, I did not. I'm pretty sure I didn't. Well, course is the basis of gase. But, you know, in, as I said, in the freshman physics class was really advanced for for that. There were different versions of it, but the version that was the kind of for serious science students was quite, so we used Purcell's book. Oh, okay, great book. I mean,

Alexa. Dynamics, yeah. So I herself, great. I don't think the course covered the whole book, but I read the whole book. Yeah, yeah. It was a great book. And great scientists, a lovely man. I was so lucky to be in. He was there. Yeah. And, but, you know, I'm going to ask you this question. I know part of the answer, because I know one of my great joys of our years of research together is our mutual joy, of looking at, of sort of entering new fields and, and learning new things and discovering,

first of all, how much is known, which is amazing and how with the work of endless scientists and on every question you can ask for, but the joy of learning your things. And, and I've also, I'm sure you said, I assume you're going to agree, I told people I'd learn a lot more physics after my PhD than before. Oh, well, in my case, that's, that's, that's, that's, by order magnitude. Yeah. Yeah. But I was going to ask,

without, have you, did you experience when you became a professor? You must have, but I imagine you, we all have to some extent, but since you hadn't taken

a traditional physics curriculum and presumably you had to teach it, unless they saved you from teaching major courses, but did you find it? Sometimes you're playing catch up that you, that you, there were areas where you say,

yeah, you were assigned to teach a class and you had to learn it? Kind of. I, you know, I, of course, made a point before I would teach a class of getting familiar with the material. And, you know, if it was one of these classes like freshman physics, that there are many different parallel classes. And yeah, I made sure that I read the text that when they were signed text, I read the text beforehand. Of course, you know, if I didn't get to pick the text, I would read whenever text was, was recommended. So I did that, but what I didn't have and where I really did have to do some catching up was in solving problems, solving the kind of problems you find in mechanics books, especially. Yeah.

and it's rolling on top of other things. And, but also electromagnetism. I, especially, the hardest thing in electromagnetism is the units. Yeah, I still have to redo it every time. To this day, I struggle with the, that's right. I remember working together, you and I, and we were working on, I met him with those accents, or a better, He was trying to get the units.

What is the... Oh, man. What a night. But now you can just ask chat GPT. It'll give you an answer, which isn't necessarily right. Exactly. That's what you can ask it, but I wouldn't trust it. That's right.

Yeah. Yeah. But so you... I want to get to Gage series, but I... You did get to Gage series, but I... You did get around. And maybe, maybe, knowing David as I do, he would, he would, he was a good judge of talent and not talent. And, and, um, but he probably said, okay, this is someone I want to grab. But did, you know,

part of, as you point out, it was a low point for theoretical particle physics, but somehow, that's what you gravitated to. Did you, there could, they were good at their, Phil Anderson. There were other great scientists at, at, at, at, at, at, it wasn't there at the time. It wasn't there at the time. Yeah. So, Bill Labs. Yeah. So maybe there was nuclear physics, I'm But were there other, did it, why particle physics? Because the, it was not particle physics as such. It was a renormalization group. It was the mathematics of particle physics. It was the mathematics. And of course, you know, relativistic quantum field theory. That was, you know, my, my education was very top heavy in that sense. So I learned in considerable depth, relativistic quantum field theory. But my knowledge

of classical electromagnetism. And maybe even quantum mechanics itself. And quantum mechanics, that's true. Yeah. So, you know, quantum mechanics and the sense of the elementary parts and the experimental axis in atomic physics, I was pretty shaky, although, you know, that, how should I say,

being very comfortable with linear algebra and group theory goes a long way there. and functional analysis, which I, you know, things I did know very well. But so I was able to master the equations very, very quickly ensuing. I read Dirac's book and really devoured it. But the process of mapping those equations onto phenomena, I had to pick up over time. and I was totally ignorant of condensed matter of physics at first, so I had to pick that up.

Did you ever teach a Stichl's Mechanics class when you were in? No, no, I don't think so. And you ever took it, I assume? I never took it, no. Okay, obviously it's been important. It's one of those areas of physics that, you know, I was forced. Oh, actually, no, I did have an undergraduate class from Friedrich Rife at Chicago. No, I'm sorry, from S. Courtney Wright on Rife's book.

But it didn't go very deep. Yeah, and it's one of those areas that's important. You don't realize it's a later, you're forced to do it, and not wonder why you're doing it. And it's essential to so much. Well, okay, so now let's, you said something which intrigues me, because David said something else a number of times publicly and also to me, that David had sort of converted, you know,

we know he was Jeff Chues, student and which was and Berkeley was a spring theory at the time. And and he said he sort of had converted to, he would talk quantum field theory and it converted to it. But David's words, and one never knows after the fact, of course, what's a recovered memory and what's real. But was that one of the reasons he was working on what he was working on was to destroy quantum field theory. Yes. Oh yes. He was very, you know, that's true. It wasn't he was converted. He was convinced that the last remaining stumbling block to having a theory that made sense was to prove that, that if you wish,

a non-a-eague-storries weren't, weren't, you know, that weren't asymptotically fleed. That would have been the last, and he had a program of showing that it was impossible to realize that the theoretical, the experimental observations,

like technically bureaucain scaling. Yeah. Within quantum field theory. He was convinced it was wrong. Yeah, and yeah, so he wanted to, he still, I mean, he always wanted to be a revolutionary. And that was clear. And yeah, he, I, but part of that process was he, you know, he was taking quantum field theory very, very seriously. Yeah, he would, he was, he was a, yeah, he devour, you know, he said,

intellectual tends to bounce on things and go deep. And so the idea was to take it serious enough to prove that it didn't work and take it serious. And also, you know, but also some things did work. You know, the, you know, maybe the full apparatus of quantum field theory somehow would fail, but it would fail in an interesting way because there was clearly something correct about the part-time model. That was inspired by quantum field theory. There was clearly a lot correct about quantum electromagnetic. I was going to say quantum electromagnetic is pretty good.

The best theory we still have, I guess, in a way, or at least the most precise. But, yeah, so you're right. There was clearly, obviously wouldn't do quantum, field theory. It hadn't been built on success after success. It was the string group was a small, you know, contingent. I mean, the bulk of the field was working, you know, based on quantum field theory and all the people, most of the people in particle physics were, were focused on that as, as, well, no? In the strong interest, yeah, well, I mean, clearly in the, in the, in the electro-week domain. Yeah.

That was quantum field there for sure. And the strong. The strong. The strongest time for that. In retrospect, in 1970 when you started, I, you know, Steve, obviously what is now the standard model. And I know that Steve, which came out in 1967, I don't think had a single citation till 1970 or 71. It had very few, that's right. But the work of at Huffton-Beldman, I think, really brought people's attention because they had done something. They proved that renewal was a theory that made sense. It wasn't just a- Yeah, that could take care of the infinities, which was making. maybe the most glaring problem of quantum field theory.

Maybe even more severe than the lack of purrachain scaling. But you know, but you know, most people, if I remember career, and I was kind of an outsider at that point, but most people were toadling along, doing different kinds of phenomenology, not really, no, how should I say? Not the prospect that you would suddenly have a working real theory of the electro-week interactions, let alone quantum chromodynamics, was not in the air, I would say.

No, people were going about their business. You know, they didn't, how should I, they didn't know that the world was changing. Yeah. It doesn't know to have this change. No, you don't, it, and it happened very suddenly. And the, so people were going about their business in different ways, doing phenomenological models of this and that, fitting experimental data. Yeah, and I think, I think, yeah, people were doing what they could do, which is what

academics do anyway. I mean, take the tools they had and trying to apply them and for most people about their career, but, for many people anyway. But you're right. I think that, you know, the atoof development thing, which showed that there's the hope of having a theory something other than electrodynamics that might be complete was. And also that you could apply rigorous mathematical methods to the fundamental interactions and make progress with it. It was a kind of change of attitude. It was a change of attitude that you might be able to do that.

But there was, you know, the groundwork was laid by earlier work on. current algebras and they would use serious people at princeton had a play the role in as well you know yeah yeah right that absolutely um so all that you know it's clear or in retrospect but but that was also indicating that there was something very right about quantum field theory yeah and galman and working on that as well. And, and, um, but the, the thing was that, that, I guess, and my perspective, and you're, and you're right, I, I, I was just beginning an undergraduate then. Um, and was, but in retrospect was that the new work demonstrated there was hope that quantum field

theory might, you know, from fundamental principles, you might be able to extract things in, areas other than electronemics, but it looked, but the, but the one area that looked hopeless was a strong interaction. Exactly. Right. I think, I think it was the dedication of, of, uh, fine hole. Uh-huh. In 1970. It was a new building, by me, I mean, when I, when I first went to Princeton as a prospective graduate student, it was kind of a sea of mud in this. Anyway, they, uh, um, At the dedication, Freeman Dyson gave a talk in which he said that the problem, the strong interaction, wouldn't be solved for 100 years. It didn't, yeah, it didn't.

Yeah, it looked, it looked hopeless, and it looked, and enough that people were looking at string theory in any other way you could try to do it. And it looked, it looked as if, well, a very reasonable expectation would have been that it would wind up something like the way nuclear physics is to this day or molecular physics. So you'd have rough theories that correlated a lot of data and were very useful, but were not mathematically beautiful or fundamental in the sense that you had equations which were precisely defined and algorithms and, you know, If you could actually, if you could solve them and they gave an answer which disagreed with experiment, you would be upset.

As opposed to just, oh, well, I have to change this parameter. Yeah, exactly. I mean, yeah, they were falsifiable in that sense. But yeah. Yeah, okay. And so, and but as I say, wasn't David's work at the time wasn't meant to say, well, I really have hope. It was to say, if we can show, if we can show that that, that, that, that, the, strong interaction can't be described by quantum field theory, it'll at least tell us that we're not

going down the wrong track and we can focus on others. And that's where he was when you met him, basically. Is that right? Yeah. And take me through, I mean, I want to talk about a lot of physics, but I think, you know, obviously, since you guys win the Nobel Prize for this, I think it's, it's worth going through this in a little more detail. Take me through the process from your perspective. I've talked to David about it in any case. You know, you came in and quickly got up to speed about at least what the problems were and what he wanted to work on.

And how did he approach it and what did you think and what did you get involved? My first priority at that time was to get a thesis project. And so we talked about a lot of things. I actually wanted to work on electrical. or weak interactions because I thought that was more ripe. Yeah.

The radical exploration and these, the, the gauge theories of those interactions were brand new. People were still experimenting with different kinds of models. It looked, the Higgs mechanism looked kind of artificial. Still does. At least, at least it wasn't obvious that the minimal model was the right. thing. And so they might be low, low hanging fruit there. It wasn't clear that you couldn't learn a lot more about the pattern of masses and mixings by imposing additional symmetries or somehow understanding things better. There were a lot of processes to be calculated. Okay, but given

David's interests and also the fact that I, attended these lectures by Wilson and so, you know, we were sort of on the same wavelength. I thought a very good problem would be to see if this problem of the Landau Singularity, which was known to be a fundamental issue in quantum electrodynamics, whether that got solved within the context of ElectroWeak theory. And you want to just explain to people what the Landau Singularity is, the force becomes strong. It's basically, you know,

to oversimplify quite a bit, it's the issue that if you calculate how the interactions behave at very short distances, you find that they get stronger and stronger and kind of the equations break down. They become infinity. equals infinity if you try to take the limit the size all the way to zero.

Yeah. Which is kind of embarrassing because the starting point of the models is particles that are points. Yeah, exactly. Yeah, that's right. Local field theory more technically, but basically particles that are points. So the interaction is formulated in terms of what happens when they're absolutely on top of each other. But that's precisely where the theory breaks down. So that's the issue of the Landau singularity. It takes a much more precise time. Basically, the idea that the theory couldn't be purely fundamental, because if you followed it to what you thought was his natural conclusion, you'd come up with mathematics. You'd come up with nonsense. It destroys itself. So, and that was known since Landau to be

the situation in quantum electrical dynamics. I mean, there were speculative ways out, but that was sort of on the face of it, the way things be. There was no simple, straightforward way out, which would have been that the couplings, in fact, don't get strongly as you picture. Anyway, so I just wanted to,

so in the context of ElectraWeak theory, that was an open problem. You know, the theories were new, and nobody had calculated different. normalization group properties. I thought, oh, that would be a very good thing to do. And it fit beautifully with David's program of, you know, showing that all theories had this land now singularity in some form. And so, yeah, so he was very, very encouraging about pursuing that particularly. So, so, so that. Okay. And then so, but you were still thinking electa week at the time,

no? Or was he was he? Yeah, I was still thinking he electra week, but, but really I wasn't even thinking about at that point it was a mathematical problem. It was electric week. How does the normalization? Not a billion gauge theory and you're probably, how does it work in non-a-dialing these theories? How does it work in this time I asked this? Yeah, and how does it work in this class of theories where it question hadn't been posed. And to just step back for the, for the listeners. So, you know, the standard, the model of all quantum field theories is quantum electronics, the theory of electric inter, the quantum theory of electromagnetism.

And it's, and, and this, there's the mathematical symmetry that, that's associated with, it's of a type of theory called a gauge symmetry theory. It's the prototype of all of the modern physics theories for the most part. But it's a particular type and it's called a, billion and and and the weak interaction involved and eventually the strong interaction involved was something called a non-abillion it's it's where carriers like photons in the case like themselves have a charge have a charge under their that's right and and so that basically in in electrodynamics there's one kind of charge electric charge it comes positive and negative

but there's one one kind of charge and in the electro weak theory they were two kinds of charge. And instead of having one photon, you have three gauge bosons, and the W and Z bosons, basically. And the thing is they can change, in addition to responding to charge, they can change one kind of charge into another.

And so because they have charges conservative, if they can change one into the other, they themselves have to carry away the charges. And so they interact. with each other too. Well, that's what makes it a different kind of theory. Makes it more complicated and more interesting. Yeah. Well, the equations look remarkably similar.

They're not quite the same. The physical difference is as vast. Yes, as eventually you guys showed, among other things. But, okay, so you're there interested in this Landau Singulari and the non-a-billion, what we would call non-a-billion gauge theories. what happened next between your David? Well, we calculated. I mean, he said me to calculate the beta function.

That was clearly the thing to do. The beta function, by the way, first of all, I wanted to clear away some formal questions about whether the renormalization group equations were gaugent variant. You know, what exactly? Because gauge theories contain a lot of stuff that's not has is not physically meaningful.

Yeah. You have to kind of make sure that you're not calculating that. So there are technical problems in doing it. So I wanted to first wanted to convince myself. And then I wanted, I needed to tool up and how you calculate these things, which, you know, now is, is, with my The modern theoretical technologies is very straightforward, but at the time, there really wasn't the infrastructure to do it. There was something called dimensional regularization, which is what had Huffed development developed. But I didn't like that for some.

I didn't like the work, the idea of appealing to fractional dimensions. I don't know why. It was good for you. also seemed so it seemed artificial to me. I also wanted to do it in a way that was easier to calculate with. So I sort of wanted, I used my own methods, which were just putting in ultraviolet cutoffs and looking for logarithms in a kind of special cookbook manner throwing away power law diverges is just keeping your logarithm, that I needed to check actually worked on the where and the known examples. So I checked beta functions in different theories and checked that

these methods worked and calculated in different. So there's a lot of preparatory work. Of course. And then it was just a matter. Stop you for a second, Frank. Just so this is great. just so people realize the beta function is something that basically is the tool the indicator to tell you how the theory looks when you go to very small distances how things change and whether they get ridiculous or not in a sense so it exactly it exactly could answer this question of the landau singularity so sorry to interrupt but go on then so you got you tooled up and it was necessary to do that anyway and great and good for you obviously to check that us that these things work because I mean I think that's another thing that people maybe it's worth stressing you know

I do these things for reason I think sometimes is to give people a sense of what science is really all about as well as other things and and you know ideas are great but but but um as lineland once said to me at least it said to me you could don't do nothing knows nothing I later on said if he can't understand it but but but but the heart of at least physics is to be able to calculate something, to actually be able to do something and compare it to, and to know that you're doing it, you have control of what you're doing,

and you need the techniques. And that's where the hard work often is. It's easy to analyze. It sometimes is, yeah. So sometimes you can get by with concepts and minimal calculations. But even in that case, it's important to,

check that you're not kidding yourself. Yeah, exactly. By doing something, some calculation that might give an answer that would disprove what you're talking about. Yeah, yeah, yeah. Because otherwise, if you can't, if you can't, how should I say, if you can't have a surprising consequence of what you're doing. So some calculation gives a specific answer or not.

It could be a thought experiment or could be. it could be some kind of calculation. Anyway, whatever. But yeah, it's really important to work out examples of what you're talking about. Because otherwise, you're maybe not talking about anything. Exactly. You might only something. The, so I'm sorry.

I'm sorry, where were we? No, no, no, this is good. So we're talking about now that, you know, now that you had, convinced yourself, you had something that wasn't meaningless. and could potentially. I had the tools. Then what happened next? I mean, who, well, I mean, did you, I should ask this, you know, because I've never asked

the way, did you do this independently or did you go to David and say, don't understand this? Or did he give? Oh, I was talking with David every day. It was, I wouldn't say it was a process of me asking for help, although that did occasionally happen. It was more that I was using some very unconventional methods and he needed to be convinced. So that was kind of, I had to show them different examples that it actually worked and produced known, reproduced known answers that I could, I could calculate in due ED with different gauges. with different, how different,

how should, calculate the renormalization in different ways by seeing how the charges of different things, renormalized, things like that. Okay, yeah, so that's good.

He was challenging you to just. Yeah, he was challenging me. That's right. He was very interested in the calculation because, although, you know, for me, it was this kind of abstract question of Landau singularities.

For him, he, As you mentioned, for him, it was part of his program of showing that quantum field theory could not describe strong interaction, could not describe Burek could not capture this phenomenon of burekane scaling. Which was, and the phenomenon was that part of it was only, you know, I had gone to Wilson's lectures and I talked to David. I picked up a certain amount by osmosis. But I, you know, he was aware of. operator product expansions, dispersion relations that give you some rules and all that stuff at a much deeper level than I was at that point. I was a quick study too, but he knew that stuff. Yeah, he knew the big issues, and you were focusing.

Yeah, he knew he was coming at it from the point of view of the strong interaction. So I was coming at it from a much hazier kind of general. And let us say that, again, one, I'm always worried jargon, but so for people, Bjorkin scaling, which was really the result of an experiment, which seemed to suggest that somehow these objects inside protons, which might be quarks or might be something else, acted like they were weakly interacting in very small scales.

And that seemed crazy because the strong interaction is lame because it's a strong interaction. Yeah. And in retrospect, although I'm not sure when I made this connection, or David or both of us. But some, the idea that if you solve the landau singularity, by God, the interaction would be weak. And that way exactly. So just putting that two and two together.

Well, I guess we knew it, but we didn't know we didn't know we knew it. If you know it, if you know it. Often one doesn't think, often one doesn't think seriously about these. questions until one actually some right some yeah I found that in physics a lot and until it was forced on us yeah and often it's experiment by the way I mean you and I both had this experience but sometimes there's things after the fact I thought well I could have done this a long time ago but after the experiment is done it suddenly causes you to think seriously in this case it was after the calculations of it done these really began yes right so yeah so so the calculations they they were kind of drawn out it took

several months because I because I was using these unconventional methods and I wasn't absolutely sure about the gauge invariance I wanted to calculate many gauges in many different ways or so so you know that's technical but the basic ideas I wanted to do the central calculation in many different ways that should give the same answer but in practice if you the algebra is sufficiently complicated, that it's a very non-trivial thing to get it all to work out. So that took several weeks. I'm surprised only took weeks.

So when were you both convinced, first of all, in the case, and I don't know if you honed right away in SU3, or just on what is eventually. No, no, there was nothing special about three at this. No. Yeah, at that point, it turns out to be. because it is a theory of this interaction, but it's, yeah, but at the time, it was just a math, you know, three, five, you know, whatever, two. Yeah, for me, it was, that was not a big deal. Uh, I hope. There were other reasons that people would have been on three. I was almost tempted to just you. No, no, yeah. I mean, it, it came pretty much for free to do much more general theory. We also, I was also, we were also very almost basically from the beginning because I was calculated. in different ways of renormalizing.

I wanted to renormalize the charge of scalar particles and spin one-half particles and gauge bosons. So make sure they obeyed the same rules, which they're supposed to do. And so, and, you know, group theory was like my native language to me. So I was able to, it was not difficult to do things in full generality. that got paid off to but some so so yeah as they say you probably weren't as focused as david was at the time or other people on why three might be the right you know why is there are

lots of phenomenal reasons that people have thought of of so i as i said i wasn't thinking about the strong interaction at all at all really so when did you when did you guys when did it happen the moment where you convinced yourself and each other i had um you know many different ways of calculating. And one by one, I found the errors until everything agreed. So I sure was, I knew I had, I could have great faith that this was the answer. And it was gauged invariant because I'd calculated many gauges. So we went to David, and we went over it. And he was very skeptical about everything. I mean, challenged everything, but especially he was skeptical about the sign of that because as, as you mentioned, he wanted to disprove

the quantum field theory. That, that was, and he thought it was obvious that, well, I don't want to slander him or purport in his mouth, but, but the, he, he would agree with that. He clearly thought that the reasonable answer was that the interaction would get strong, and you would have this Landau singularity. But the calculations were looking, were looking the opposite. So we kept saying, well, are you sure? Are you sure?

We went through it. Did you ever get a positive sign and have to discover you made an error or no? Did you guys? It's a natural question. I think I'd ask you. I'd like to say no. David would say he said.

I had the sign. He tried to argue me out of it. He's what he had. But I just wanted to have, at some point, I was just wanted to have peace. And so, okay. And, but, but, you know, it was, so there was a few days when we argued about it.

It was unsettled, I would say. but no, we never, we certainly never approached going to the world with the wrong sign. Okay, so let me ask one question, and then I'm going to let you take another three or four minute break for the last, the last, whatever, however long we spend, it'll be less than an hour, up to it or equal to an hour. With the rest of my career. Yeah, no, no, it's a post. We've covered about six months. I know, I know, I know, but it's, this. This is important. We're going to talk about the rest of physics after we asked some thought of freedom in the next hour. Well, we always spent an hour on this physics. We've spent an hour. But anyway, look, this, I think it's all interesting, and I hope people will too. But, um, okay, so you have the sign. How long, I mean, did you really, you were a graduate student, you know, from math. Did, did you, how long did it take for you to appreciate the significance of what you guys had? And, and maybe David did.

That's an interesting question. I have to answer it in two ways. At the level of abstraction, I said to myself and to David at the time, look, and it says in the papers that if you take quantum field theory and the phenomena at face value, this is the theory of the strong interaction.

No real choice. you know, it's, it's, and I said, and I thought that was absolutely clear. And I said to David, you know, if this is correct, we'll get the Nobel Prize for it. And he said, it's not that kind, it's not the kind of work you know, prize. So that's at one level. Then at another level, though, so I kind of, at the level of physics on the ground, what it takes for a community to be converted to a new point of view, what in terms of experiments being

mounted, international conferences, talks, and what it means for a theory to be accepted and to be successful. That I didn't really get. I didn't have a feeling for, I didn't have a feeling for what that would be like at all. The first kind of impression I got, which made a big impact on me. It was the first kind of conference I went to as a participant, as opposed to an observer, was a small thing at the Downing Town Inn in Connecticut

where Feynman was attending as kind of the, you know, the superstar. It was a small thing, maybe 50 people. And at the conclusion of that conference, he advertised our work. He said, you really got to check this. I mean, you know, it's probably wrong, but, you know, it makes a definite prediction for how the bureaucratic scaling should break down, you know, makes a definite prediction. And you've got to. So that's, that's important to check.

And so he was very skeptical, I would say, but very interested. Well, that must have had a big impact on you. Oh, yeah. It was, I was staggered, almost literally. Was David there too or just you? Was David there too or just you? David is not there. Tony Z. was there with me.

But you were there alone. Okay. Well, okay, good. I mean, that's obviously a pivotal point. And it's interesting to hear, you know, one off, well, it's not, you know, it's amusing to me that you I was going to say one isn't often aware of the implications of what one does

one way or another till after the fact but the fact that you thought I'm not surprised but I'm amused that you thought well this is the theory of the strong interaction that should if it yeah that's the way I mean that's I thought about it that's the level I thought about but it partly shows how naive I was I wasn't really a member of the physics community

I was this you know I still went behind the years basically a converted mathematics graduate student who knew this very small sliver of physics and had done something. But I didn't know how the community worked. I really was very naive about it and didn't know the scale of it or what, you know. Well, it meant you still have great hopes when you went to win the Nobel Prize. That's nice to know you were aspiring high early. But okay, Now, here's a question, Frank. Do you want to take a break for three or four minutes or do you want to just continue? Okay, Frank, great. When we last spoke, and you were in a slightly different location, we had just completed the work that won you the Nobel Prize and talking about that time, which was obviously an important time for you and for science. I want to move on obviously now to the subsequent career of yours, which has been remarkable in many ways.

I still, there are lessons to be learned here that I still think is interesting. You after, am I correct that after your, after your work, you stayed on, I mean, you got a postdoc and then almost immediately assisted your professorship at Princeton. You didn't go anywhere else, am I right? No, no. And I didn't really do a postdoc either. Yeah, you just immediately became an assistant professor more or less. Yes.

And I have to ask you how that fits. in the sense that, I mean, it's not often, that's the case. And you've just done work, which was, you know, even maybe not immediately, but within short time being appreciated as a pivotal development in particle physics. Yeah. And I'm wondering if it was difficult to adjust to that, newfound, now, I guess. Well, it wasn't a matter of adjustment. only thing I knew. Yeah, it was anything you knew. So it's just right. That's true.

Life was normal. That's important. But you never felt any any any any any issues of demand. I mean, whether well really or or felt a compulsion, you know, a pressure on you to keep at that level and et cetera, et cetera. Well, I certainly wanted to keep. doing the best work I could. And I also felt that now I was a physicist, that the die was cast. And so I had a lot of catching up to do in terms of learning the whole of what it means

to be a professional theoretical physicist and being able to teach the courses that are expected that theoretical physicists can teach, but also to exploit this discovery because it opened up quite a few new directions. It really opened up early universe cosmology because the thick veil of the strong interaction dissolved at very high temperatures. Yeah, it's meant that high temperatures were suddenly and high energies were suddenly accessible and that one could talk before,

now one could calculate or at least argue certain things with confidence. Yeah, or at least with credibility. Yeah, that... So, as we discussed earlier, the whole renaissance of quantum field theory taken literally, not just seriously, but literally, was a new era. You could now apply it with credibility.

Yeah. A bunch of things that you couldn't before. It opened up a whole thing. Now, it's not to say you left, I mean, you guys, I don't, I assume I don't know the history, but I mean, there were substantive papers building on the asymptotic freedom work to compare it to experiments and do the confidence. later on be essential, frankly, for winning Nobel Prize in the sense that you have to have experimental confirmation of these ideas. And so the long papers that you and David wrote, and I assume they were after your thesis and after you.

We wrote, well, it was all happening at the same time. It was all, all the work was of a piece, but there was a letter and then two long papers. And, of course, you know, there was a lot in the paper besides, in those papers, besides. the bare bones calculation proposing a theory of the strong interaction drawing some obvious qualitative consequences

but most important I think calculating quantitative things about how the theory differed from a naive

heart on law people were working. So we wanted to make quantitative tests that were really characteristic of the theory because the theory was

absolutely specific. He had definite equations not easy to solve, but we had certain things we could we could get at. And we did a lot of calculation to exploit that opening. And we also, in those papers, we also explored theories that weren't theories of the strong interaction.

We extended it to not-abular-engaged fields interacting with other quantum fields. just as field theories. So things that later became important in thinking about unification and just the nature of quantum field theory. So there's a lot in those early papers. And we were given a great gift because this discovery was extremely highly leveraged.

and we were in a position to use a lot of tools that had been developed now with concrete targets, as if people had long ago invented hammers, but now we had nails that we could use for something. And then so that was in the first wave of paper. papers, but then in the next few years, there was the application to high energy, further experiments in high energy. I mean, one that I'm especially proud of is figuring out how the Higgs particle, which at that time was very hypothetical, would couple efficiently to ordinary matter. This is through gluons that turn into quarks, heavy quarks that then turn into the Higgs particle. And that was many years later, that was actually the way it was finally produced, whereas the ideas prior to that were not

very practical of how you didn't. Because you didn't have a theory. Yeah, you didn't know, right. And so So the whole idea that you could use the first of all, that you could use protons as a source of gluons, that that was the right way to think about what protons are in this context. And then secondly, that the higher order processes involving quantum loops, which people don't remember now, but prior to the early 70s, those were kind of really exotic things having to do with small radiative corrections in atomic physics or not even ever measured corrections, futuristic corrections, and weak interaction processes.

But now in QCD, they are often the leading effect and certainly big effects. There's a very strong. Interrections are stronger. But not but weak enough that you can still use. Yeah, the Dervently QC. Yeah, so that was, you know, that was a combative shift. And so the early universe.

Well, I want to get to the early universe a second because I think, you know, I want to, you know, I think I want to point out that, you know, it was important to follow up and you guys didn't look a gift horse in the mouth and that followed up and looked at the direct examples of how that could be used in the, in the domain in which it was originally sort of thought of is how can you use strong interactions.

And to be fair, that was all those also, those that work laid the groundwork for what many years later would be the experimental ability to confirm the idea is enough so that, so that, so that, you know, a committee in Stockholm. Yeah, well, yes. The blessing and the curse of QCD from our point of view is that its predictions were very specific and very falsified. So the So until the tests were really definitive You know, the The Nobel Committee didn't want to Rightly so

Do something that was wrong Something that was then proved to be incorrect Yeah That's an important part of it What I worry about But nonetheless you didn't want to The tests became very easy When the mission

When the accelerator has got to really high energy Yeah But for many years, they were kind of semi-quantitative. Yeah, because they were at the domain where you really, you know, where the interactions weren't quite weak enough to disentangle. And even the, you know, and even probably certainly one of the, the important discoveries of a charm, yeah, its quark was, you know, just in the domain where you, it.

Right. It was very encouraging at a kind of. of semi-quantitative level and that converted the theoretical community I think to somewhere between just accepting the theory and taking it very very seriously but it was it didn't have so it didn't it didn't fulfill the full potential of the theory, the full responsibility of the theory to really provide precise comparisons with data. It was supposed to be a unique theory. It did make precise predictions.

It's just they were difficult to test with the available energies. Yeah, eventually the available. computer technology. Now it's a very different story. As you pointed out, I'm pretty sure you, but in any case, now that it's well enough understood that that important theory is now the background against fish. Yeah, it's regarded.

So I lived to see this process, which was quite interesting and a little bit bittersweet to live through, but the the tests of the theory in the early days the outcome was not completely assured was a matter of great

excitement to the community. So at big international conferences, you'd have sessions on testing QCD and the plots would get better and better with time. And they seem to be converging on the theory and they got more and more quantitative. And also, I should say, not only the experiments, but also the calculations got much, much better than what we did. You know, we did basically one loop calculations.

And now people routinely do three loop calculations, which are much, much more difficult. but necessary to, I mean, the theory supports that. And it's important because you need to know the predictions well enough so that you can remove. Yeah, well, now, as you said, the same kind of activity that was so exciting called testing QCD is now done much, much better on both theory and experiment. but it has a much less glamorous aspect to it. It's just, it's called calculating backgrounds. People are absolutely convinced that that's, that this is the theory,

and you calculate with it very accurately. And it's regarded as a background to discovering new physics, something that's not already known. So far, the new physics hasn't really materialized very much. Yeah, exactly. But it's the way to do it. If you know the QCD prediction, you can look for a deviation. It's trusted well enough that a deviation would no longer be viewed as a sysious test of the theory,

but would rather be evidence for something new. Yeah. And the discovery of the Higgs particle was especially remarkable in this way, because you could calculate based on QCD if there was a Higgs particle of a Gitt mass, what the signal would be, what the backgrounds would be. So how good the experiment had to be?

And if you did see a deviation, what exactly it would look like if it was a Higgs particle, without that, it would have been hopeless, would have been absolutely hopeless. Because the actual discovery of the Higgs particle if you look at what the data was, was a little bit of an enhancement in a particular cross-section of an invariant mass for two-photon production. And it's not a very impressive statistical enhancement.

And it's statistical. It's not any particular event. You know, it's just there's more of more there than there might have been if it was just QCD. So that's, you know, that's, it's, and it's worth. pointing out that not only has the theory become background, but, but the incredibly complex at the time calculations you performed, I know that having taught quantum field theory, engaged field there a few times I've given out as a homework assignment. Yeah. It's a calculation because it's now a homework assignment. Right. Although, although if you

get, if you, uh, ask the class to do all the calculations I did, do it in, do it in different gauges. Yeah, that's a different thing. Do it for the different definitions of the coupling, depending on, then it would be at least a pretty respectable problem set. Okay, now, but now, so now, as I say, let's move beyond. So, Princeton, you know, as you point out,

it opened the way to a lot of new things, including the confident application of particle physics cosmology. And I want to say, you know, that was from the point of view of a field, an area which you moved into and the whole field moved into in some sense. I think it's fair to say, Steve Weinberg had been thinking about this for a while. And now. Yeah, so he was ready for it. He was ready for it. And I was ready for it because of Steve Weinberg in his cosmology book, which came out, I believe, in the early 70s also.

So just just. Just gravitation and cosmology. In 1972, I think it came out. So I read that as I was learning, you know, becoming a physicist, so to speak. Yes. And at the very end of the book, he discusses the very early universe.

Yeah. And how it's very uncertain to discuss the very early universe because of the strong interaction. And, you know, so I knew that. part by heart. I was all, you know, then as now, I was always looking for opportunities. What is poorly understood.

And I realize now, now we could do it. Yeah, no, and well, exactly. But there was another important development that I think spurred it. But, and I want, and what you were involved in. I think the first time I heard you lecture was associated with this particular thing. But, but I guess I want to ask this, another sort of sociological, psychological, psychological

questionally this. You are now an assistant professor, but I'm sure there must have been motivation for you. Look, you've done this great work with David Gross. And you want to be, and I, and I'm sure at the time also felt like you didn't want to be seen as, you know, a mere David Gross protege in that sense. No, that's right. Be seen as an independent scientist. So it's important to move out. And I don't know if that pushed you as well to look for different problems that were remote, somewhat remote from the problems you're working on to demonstrate you as an individual physicist and you're... Well, that I'm sure wasn't absent from my...

Yeah. Altogether absent from my thought. But really, my style was before asymptotic freedom, immediately afterwards. and all the way to today to try to skim the cream of things and then move on. Okay. Yeah, go in, get a hit and come back. I know exactly. So when the going gets tough, the tough run away, that's right.

That's right. Well, you know, the reason we walk together is that we have that same attitude. Let's go find it, find a crux and then move on. So the idea that I wanted to go really set out on my own, well, my original interest, as I mentioned before, was the weak interaction. Yeah. So I moved into applications to the weak interaction and unification and cosmology. So that's sort of what I intended to do all along. The strong interaction as such was never my goal.

That was kind of an unexpected gift. just, you know, looking for, looking for applications. And, you know, another very valid thing to do was to try to use this tool to really understand the strong interaction. So to understand problems like confinement. Yeah. To do more accurate calculations, calculated at higher and so forth. I did dabble a little bit in trying to do, non-perturbitive calculations. In fact, lattice gauge theory. Yeah, well, we'll get to lattice gauge theory. And I actually worked with that, on that,

with Tony Z and Ed Witten. But it never got very far, largely for the very practical reason that the computing just wasn't there. Yeah. We had, you know, you had to go down with punch cards and put in something. And then they would give you error messages that the semicolon was in the wrong column. And 20 minutes later and then you start all over again.

And if you did get output, it would be at another building. That was a very different kind of experience. And yeah, so it got pretty old, pretty fast. Well, now let's talk about it. Yeah, I can imagine. But we'll talk about a lot of stage there, which I think is really a lot of SucD and a herald it may be near the end. But you hit a key point in my notes, which if I look at where I next knew of you, it was

in the next big heyday, which really resulted, well, from the sudden realization that the electric week theory was right and that one had a theory of the strong interaction. But most importantly, that something that I think had been. known by some scientists, like Landau and Lowe and Galman and others, but not by the whole group, that this idea that the strength of coupling constants can change, the strength of an interaction could change at the scale of which you do it. Obviously, in this case of astrotomy freedom, central to understanding a theory, but it now keeps central to understanding all theories, it changed our perspective.

The theories are now no longer fixed, that they're a function of the scale at which you measure them. Yes. And it raised the immediate, for those who saw it correctly, an immediate opportunity that we now had theories. We had three non-gravitational interactions a week, electromagnetic and strong directions. They each had different strengths, but that was only at our scale. And it was really begged people to think about what happened at a higher scale. And a few people didn't begin to think about it. So maybe yes. Yeah. Well, the gang at Harvard was a, very quick to jump on that. In fact, Georgia and Glashow had been thinking about unification without worrying about the fact that the companies were unequal.

Somehow that would take care of itself and had a beautiful unification of quantum numbers in representations of SU5 and then as of 10. and then George I, Quinn, and Weinberg applied the renormalization group for really, I'd like to say it's just extending the calculations to hire in budget

and yeah, and it more or less works at that time. It changed everything. I will say as a graduate student at the time, because I was I was well I was just beginning to be a graduate student at the time when those things were but when it had taken over the field I remember and I remember

the first time I think I heard you was probably was at a meeting on grand unification or at least something like it but suddenly it it did exactly what you just said it allowed business to extrapolate ideas not just about what you might measure in the laboratory and created the, the reason to build proton decay detectors to look for gran unification. But it suddenly gave a kind of, well, one might say in a generous way, chutzpah, one might say in another way, arrogance of particle that we could extend the domain of which we understood

things, not just by a factor two, but by a factor of 10 to the 15. Yeah. And but it really. One of the, yeah, so it gave us the oldest success in understanding concrete phenomena using quantum field theory gave us a lot of confidence that that was a correct framework and should be taken very seriously. And if you do take it seriously, its problems, so to speak, arise only, well, technically logarithmically, So only when the energies get very, very large.

So there was a lot of ground to where you could, you could make applications. And suddenly, I don't know that, the changes, these logarithic changes might actually be helpful. And that's the unification. Absolutely. But they also allowed you to suddenly ask questions seriously that would have only been, well, that like Walker would have talked about in principle before. And one of them being, and I know that you use the term, why is there something rather nothing? And I obviously used it in my book, but at the time,

we suddenly, to address this, I think it's fair to say that the key, the first time, particle astrophysics is now a central area. Right. Some physics. But the idea that you could somehow explain the really one surprising number, which, again, I first learned from Weinberg, but one surprising number, why is there matter in the universe, why is the number of protons one, one 10 billionth of the number of photons and why is it zero? Suddenly you might be lanced that question and that took over the field and you were involved in trying to address that question, right? Yeah, right, right from the beginning. Yeah, um, and because the, if you combine the ideas of unification with, um,

with the idea that the early universe works in a straightforward way, which was a, was internally consistent with how, then you got more or less credible theories of how that asymmetry might have arisen. They still are not very definite. I mean, we don't know really to make any kind of quantitative to make any kind of quantitative connection to get that number. But it's not implausible that it would arise in this circle of ideas. Well, it was enough to get people to build big new proton decay detectors too to try and make predictions that. If proton decay were discovered, and I'm still hoping to see

that in my lifetime. Taking that's very troll and metformism. and MN and MN and MN and I'm going to try to stick around. Of course, if proton decay would discover it, that would open up a window into the relevant physics that maybe we could start to get quantitative about that or other things, other directions. Which way back in the 70s, I was always, already writing papers about the branching ratios of proton decay.

That would teach us. Okay. Yeah. But I think it's fair to say that this became, I mean, it's hard for people to envisage, and I've talked to both the experimentalists and the theorists involved and people like David and where you. It's hard to imagine that the amazing revolutionary change in 1965, we had really an understanding of a reliable understanding of one of the four forces in nature and within the decade after that we understood three of the four forces in nature exactly essentially and you know

as good as you could possibly measure and that gave people as you point out an extreme confidence and i do remember the feeling in 1980 uh which was i you know first time i was a graduate student that i was sort of really cognizant of what was going on that you know that it looked like you know Grand synthesis was in the air. You know, the first meeting was almost a celebratory meeting for, you know, wine, or, yeah, like we're waiting any day. We'll discover this and then we'll have everything. And, and it was, especially proton, proton decay was the lynch pin.

Yeah, it was a lynchman. Everyone was certain that would be discovered in these first generation of detectors. And of course, it hasn't been yet 40 years later. And it's sort of heralded a sense that, you know, there was all this hope and promise that has, to be fair, hasn't yet been fulfilled experimentally. Right. Right. We had, we did find neutrino masses. Yeah, yeah. Non-zero, but quite small neutrino masses, which are another semi-quantitative implication of this circle. of ideas. But in fact, stands outside of it a little bit. I mean, they're not predicted.

They're understood as being possible, but not something that was necessarily demanded of the theory, although... No, well, neither is matter versus antimatter asymmetry. They're just natural consequences. Consequences, yeah, yeah, okay. A circle of ideas. And what I thought would happen was not only that, but also the people, Well, even to this day, don't talk about it very much, but the flavor problems that why are these three generations.

And is it really, is there is, is the generation of mass or the accommodation of mass by means of the minimal Higgs coupling? Is that really the way nature works? It seemed awfully contrived. Well, it seemed like a bad joke. We have all these masses and all these mixing angles. And so if you count the number of pure numbers that go into describing the world using the standard model, it's a couple of dozen, at least. to me. At least something. And one would like to have a quantitative theory that produces those numbers. I mean, you know, we're getting very spoiled now. We want to calculate all the pure numbers.

But in the minimal implementation of the Higgs mechanism, you don't calculate any of them. You just put them in from experiment. And so I didn't believe that I couldn't, I didn't, I didn't monitor. believe that that was the end of the story or anything other than a very temporary way station. But so far. So, yeah, it's amazing. Yeah, I just thought it can't be the right way. I remember Shelley Glashire, one of his books called The Higgs Make This in the Toilet of a modern business.

We don't want to talk about what happens there. Yeah. Yeah. And in any case, so you got involved in Cosmole. I knew you from, you know, this matter of a. versus antimatter, where you were, obviously the whole, the leaders of the field were all, you know, there's got competition and everyone, there's a lot of people doing it, but, yeah, but it was a hot hurry to do when you were, it didn't require deep ideas

beyond the unification and, and, and, and, and, and, and, and, and, and, and, and, and, and, anybody could get in on the act. People did, and, and, you know, but it, you know, but it also legitimized the notion of thinking using particle physics. Because Maljean, I got involved in that early on thinking about, you know, generating dark matter. I didn't think about it this way, but I think the way you described it called to mind what happened with the Newtonian revolution. It's, it wasn't only that it made successful that, you know, suddenly you had a theory that made successful predictions of this and that. But it was kind of the meta idea that you could and should have precise theories

that made an enormous impact and that when you did have a theory, you should take it dead seriously and start to compute the perturbations on the motion of the moon and the tie, all these things. And it's not just grandiose speculation. you have a theory that you should take very, very seriously, and theories that don't allow you to do that are not up to snuff. Absolutely. It changes your level of ambition.

Absolutely. And also it ups the requirement. It ups the bar in a sense, too, because, at least it did for a while, because the theory had to predict things. I often say to people, and you know because Einstein has always used as a paradigm of this guy thinking alone in his room and it's not any none of that is true right and he was in touch at the time for me it's a statement that he made that when the only time he had a help the first time he had heart palpitations for general relativity wasn't just seeing it was real theory but calculating the precision of the perihelion of mercury that's what suddenly this small effect suddenly that's what made him almost faint is yeah yeah because that you could You had actual numbers that were. And you could push them to that level.

Now, so anyway, so the heyday of Guts is still around. It created this, I mean, Guts, grand unified theories, the notion that somehow the three forces could be unified, and it looked pretty good. It turned out the simplest model now is ruled out. I mean, without some new addition, they don't unify, and we now know that. No, but for better or worse,

if you include corrections from super symmetric particles. Well, let's, okay, hold on. We're not got to see this. And you obviously, one of your calculations that you were involved in, which is very important, is exactly that. That if all we have is what we see, there's some problem. And for a variety of reasons, and there are many reasons, and I don't think we'll go into them all for super symmetry.

It turns out if you have this new symmetry of nature, going back to symmetries and your early education, suddenly then you could, then unification is a real, then it's a real possibility. It's at least not clearly wrong. Yeah, exactly. But at the same time,

and this is another, in some sense, I want to refer to this time as hopes dashed in many ways. God's, we haven't seen proton decay. When you do this, the evidence for, and this was just one bit of evidence for super symmetry as a theory, seems so compelling that many of us, and this was certainly my view, and I bet it's your view. You could tell me it isn't felt that when the large adron

collider turned on, it wouldn't see the Higgs, because that's a hard thing to find. The first thing is supersymmetry. Did you kind of think that too? Well, I wasn't so confident of either one. Well, I was much more confident of the Higgs particle, actually, because I had followed closely enough to know that, there were accessible signatures and be difficult but not impossible.

And actually the actual Higgs mass is almost the least favorable case. Yeah, exactly. It is. Makes the experiments particularly difficult for various technical reasons. I have to tell you a little story here for a second. Three months before the Higgs was discovered, I was in Australia because I used to commute. And there was a group involved in that large island collider.

and I remember having a meeting with them. They were so confident, they said, we've ruled out the range from above, we've ruled out the range below. There's only this narrow little window that's not rolled out, and we're going to roll out the next year. That's exactly where it was.

That's exactly what. Yeah, so it was a triumph of theory, really. And so the Higgs versus... On supersymmetry, I was well aware. I mean, you know, there are all kinds of hand-waving, vague motivations for supersymmetry. But the one quantitative motivation, as far as I'm concerned, is this unification of couplings. And for better or worse, it's, it doesn't depend very

sensitively on the exact value of the masses of the supersymmetric particles. Could it be one TV, they could be 10 TV, they could probably even be 100 TV, and the calculations would still be acceptably accurate. So I wasn't very confident that interesting surgery would show up at the LHC. I was hopeful, certainly. Although the other compelling argument,

which is sort of competes with something we're going to get to in a minute, was that, you know, that these super smetriac particles could be good dark matter candidates if they were in the range that would show up at the LHC. Well, I was especially uncertain about that because I was hopeful that axi. Okay, now. I want to talk about this in an intellectual sense,

which I think I never had thought of it before I tried to put this together. So QCD made quantum field theory kosher, made suddenly applying it to unbelievably early times in this universe culture, which had its other impacts, which is string theory, which ultimately talked about. But the other thing it did is it said, well, now maybe we can have enough confidence to understand some, to try and quantitatively deal with some other real problems which had been well known,

but put aside because when you don't have a theory, you couldn't possibly explain them. And one was this nagging aspect that the strong interaction had a symmetry that it didn't really shouldn't really have CP. And there wasn't any violate that fundamentally the symmetry, if you looked at it naively, would be broken. And it wasn't. And I kind of think it was the notion that you could really, that you could rely on quantum field theory enough that you could have proposed models and model building became a big industry that would suddenly try and solve that problem. And that, and thereupon comes a particle that you named. And so maybe you want to discuss that a little bit. Right. So one of the great triumphs of the standard model has to do with. very much improving our understanding of a very strange symmetry of nature.

That is the fact that the fundamental laws to a very, very good approximation, would run the same if you reverse the direction of time. So if you look at a movie of fundamental interactions run backwards, you wouldn't be able to tell that it was run back. It obeys the laws. This is very different from everyday experience, so it's why should it be that way? And that was very mysterious for a long, long time, and was thought to be just, well, it's a beautiful principle, and maybe we don't need it, and maybe it's even an embarrassment, because now we have to understand why the world doesn't look that way. But in the context of our deeper understanding of quantum field theory and

quantum mechanics, relativity, and the structure of the standard model, its deep symmetries, we understood that time reversal in an approximate way, very good approximation, was a consequence of other deeper principles. I should have mentioned, by the way, that of course that in 1964, after decades, centuries, really, of physics having that time reversal symmetry as a feature of the fundamental law, tiny deviations were found from it in obscure corners of decays of K-Nazons. So we knew it was, it's. couldn't be an exact feature. It had to be explained. And Pobiashi and Masawa put all this together

and identified the kind of interaction, a unique kind of interaction that could generate this asymmetry, this observed asymmetry, but also that that was the only place you would see it. But then a loophole sprung up as QCD was understood better, that there's one more kind of interaction that could have violated time reversal. But it doesn't. It doesn't appear in nature to very, very high accuracy in people. It should be there, but it's not seen.

It should be a puzzle. It's like you're expecting, you're expecting, something to come in with strength unity. It's actually doesn't show up. And it's been measured two apart and 10 to the 10th. So one. It's a billion times too small. Yeah.

It's a billion times smaller than you would have imagined. So we want. Yeah. So something like that is an opportunity. It's something looks as that kind of, quantitative discrepancy anomaly or whatever you want to call it

is so striking that it deserves a qualitative explanation just as, for instance, the equality of gravitational and inertial mass deserved a qualitative explanation and that emerged

in the theory of general relativity. It was the main thing that led Einstein to the general theory relativity probably. Yeah, now, in fact, I think as Homer Simpson said, and I think I learned it from you, it's that this is a chrysitunity. So so, and then it turns out that by expanding the standard model to include another big symmetry, it's called Petchie Quinn Cemetery, you can understand why that interaction in nature is actually observed to be quite small, basically. Let me stop there because we're going to get the action in a second because, yes, they came

that, but I want to put this in the context. It was, that became the, and to a large extent still is, well, to a large, yeah, I think that's fair to say. Still, that became the business of particle physics. Once you had the standard model, the business was to look for theories or model. or theories beyond the standard model, which you could then make because of our some confidence of quantum field theory, you could make specific predictions of. And so in guts and everything else, the industry, and it's happened for the last 40 years,

it's been trying to build models beyond the standard model. Any one of which might give something we would see, which might tell us what it is. And so the Pentechiquin symmetry, this model, was beautiful and ubiquitous. It gave a natural mechanism for solving this problem. But what I guess, but what was not quite recognized and two very good physicists, you and and Steve Weinberg, realized there was another implication of that. Yeah, there's an implication of this circle of ideas, which Petching and Quinn didn't realize, which is that you get a particle, a new kind of particle with very remarkable properties.

This is what I call the axione. Steve Weinberg was working along similar lines, he wanted to call it the Higlet or he was calling it the Higlet. He did call it the Higlin in his paper. I was aware of each other at first, but we became aware.

But we agreed that Axion is a better name than Higl. Yeah, your papers appeared side by side. One of my great contributions to physics was to save the world from Higlis. the uh the uh

but yeah I actually uh had thought of most of the theory without reference to

uh Pache and Quinn but I thought I actually thought it was ruled out because I thought these axions would be would have been observed. They're like very light particles.

Yeah. I didn't think very hard about it. But I said, well, they're light particles. They're not particularly weekly couple because at that time we were thinking about what we're now called week scale axioms, which and I just, well, I just thought that they were ruled out. But then I talked with Steve and he said, no, it's not ruled out.

I don't think so. So I had to analyze it more carefully and quantitatively and write it up. And the, you know, I think it's, what was I going to say? Yeah, so, you know, they're amusing stories about how we named it after laundry detergent and. Yeah, I know. You always wanted the name of particle after axione. I know that. But it's, you know, it's last, it's, it's now, I think, become one of the great targets of fundamental science is to find this particle because it's still to this day the only, this circle of ideas is the only convincing way or even semi-convincing way to address this profound problem.

why a number that should be one is, in fact, less than a part in 10 billion. Yeah. And the axon is a remarkable particle for a lot of reasons. It's died and been reborn many times, like many saviors. And it is interesting. I mean, you know, one of the momentary bits of joy in our own collaboration was the realization, you keep thinking, one thinks it's ruled out. And one discovers there was a,

anomaly in nuclear physics measurements and I remember you and I, it was remarkable. I mean, if it had been true, the only good explanation would have been our axiom, but it's remarkable that even there, it wasn't, it took a while before it could be shown to be ruled out. It's very, very interesting. Unlike many speculations about beyond the standard model physics, that kind of fundamental physics, this involves a very light particle, not a very heavy particle. Yes, light but weakly interacting. And so in principle, if you have very sensitive experiments or look in very clever ways, you don't have to have an enormous accelerator.

Yeah. And that comes to its present observation. But also, but it is surprising that even in areas where you think it would have been ruled out and observed, it took a while before you could show that it wasn't, you know, in a case of our accent, it was ruled. we actually did work to rule it out, but, but it took a while. But the interesting thing that was, the virtue and, I wouldn't say pitfall, but one of the pluses and minuses of accents makes them, is that they're so, is that it's so,

the theory is so ubiquitous. So it was realized, well, you know, the only scale we knew over the time is the weak scale and that was the first scale. And then the weak scale action was ruled out. But then once there were new scales, once we had grand unified, theories and there was suddenly a new scale in nature that was orders of magnitude higher energy as well as well the mechanism still works even if even if it's associated with this new scale and that became what's become known as the invisible axiom because that truly was many many many many orders of magnitude

weekly more we that makes the coupling the coupling gets weaker as as this as the mass gets smaller and this and that's associated with the symmetry breaking scale getting larger But people have gotten very good. Well, no, a big thing happened, actually. A very big thing happened, which is that, and I had a major role in this, is that the early work on axions in the tradition of particle physics

just says we were in the ground state. We were in the lowest energy state of this quantum field theory, without really asking how we got there. Or are we really in the ground state? Yeah, we're close to the ground state. Or maybe not even close to the ground state. But in the context of axioms,

you had a fully fleshed out theory of how the cosmology would work if you had axioms. If you have the kind of theory in which axions arise. And if you work out the consequences of those equations, you find that axions, despite being very light, despite being very weakly interacting, that produced a lot.

Yeah, and they became the other canonical dark matter candidate. I mean, the cosmology of axions is, you know, once it depended crucially in some sense on on the existence of grand unified theories for thinking about that yeah but the fact is that these remarkably like particles can and i remember you know that you wrote a very important paper with my then Harvard colleagues i think john preston mark wise i think were the two other d peter no they uh i think they were they were still at harvard i think at that point. But anyway, I think I was remembering that when I

was with them. They were all together. But it was, you know, within a year or two, they moved to, no, thank. They were both junior fellows or assisted professors. But the, and that, and and, and, and they could easily be dark matter. The

difference was that, you know, they could also easily be not dark matter depending upon, depending upon their scale, but, but the fact, and then the next, of course, major development, which both you and I were involved in early on too, is realizing that even these potentially invisible particles are not invisible. If you're not so invisible, when you have so many of them in the universe, they, they're,

individually, they're pretty invisible. But if you have enough of them, it's sort of like neutrino or gravitational waves. It's amazing. And that's an area. I wasn't going to, we'll jump there. wasn't going to go there right away, but that's an area where you and I together spent a lot of time. And the beauty of realizing that ultra-sensitive technology is wonderful and offers opportunities to detect particles that you might not think were detectable from regular axioms to dark matter to neutrinos.

And I remember the joy we both had, I think, working and discovering engineering and technology for both neutrinos and for axions. And it was a, it's an amazing, and it's wonderful because it means that the field can move forward in principle without having to build multi-billion dollar accelerators. Canon is. Yeah, it is. And so I think that's, you know, that whole notion has changed. I think that it's fair to say that the, you know, for the moment, the frontier,

much of the frontier of particle physics lies in thinking about beautiful technologies that might even be done not maybe on a tabletop, but in a laboratory, the size of an office, or maybe a small building. Yes. And it changed the way, change the sociology and psychology of the field a lot. Yeah, it certainly expanded the toolbox and expanded imagination. Yeah. And I know you're involved in an ongoing accident experiment, and I've been involved in the past

and dark matter experiments, and still thinking, with the last papers I wrote, I'm still trying to think of new ways to measure axions. It's still, to me, one of us. Yeah, well, we together wrote papers about using materials to enhance the signal from axions. Yeah. And this new wave of experiments is in that same direction. Same vein, different. What are the, the new development for the Alpha project.

that I'm especially involved in is using not a natural material, not some kind of special mineral or something, but what's called a metamaterial, especially engineered material and arrays of wires or more sophisticated things that have, they're kind of very fancy antennas, if you like, but to pick up a different kind of signal than electromagnetic signals. Yeah, it's fascinating to see what's going to happen, and we hope, we'll hope for the best. The, although I'm still hoping for some ideas I'm thinking about, but we'll see. But, but then mentioning metadata materials is a nice segue because I want to move. Your career has gone in many different directions. Before, it's worth mentioning one, one,

thing I want to ask you about because I know we've talked about it. Before we talk about the other directions, there's one idea that was remarkable that came out of all of this that many people have kicked themselves for not realizing. And that was the idea of inflation. Yes. Which is so tied to all of these notions. And it's remarkable that it, all of the ideas that were related to proton decay to axioms and axiomology um or interrelated this this fundamental idea that that that yeah i guess that you know alan people weren't thinking about i don't know why people weren't thinking about it other than alan goof but well they were thinking about other things that's what i guess that's the point it's technically it's not that difficult or that different from uh what people were thinking about

It's just, it's just, you know, it's just, there was no hook. Well, I mean, the hook. It was a monopole problem was a hook. Yeah, the monopole problem. But the monopole problem was a very theoretical problem. Yeah. You're so worried, we won't go into it here. You had to go into, you had, I won't say what it is, but, but, but, but, to,

to really take it seriously, you had to extrapolate the very, to way beyond the evidence we have about the Big Bank, much, much higher temperatures, much much earlier times, where we didn't really have reliable theories. I mean, it was taking unified theories, even a step beyond. Well, to be fair, though, it was the same step beyond that the people who were building models of the generation of barons in the air matter over antimatter in the early universe. Yeah, yeah. Yeah. No, it wasn't a crazy thing to be thinking about. But I would say it wasn't something you had to be thinking about. No, exactly. It was a clear problem that you could define and was obvious. But I only mentioned it partly because, you know, for myself, I was, I was, I was, I was,

thinking about axions and Higgs part of things we mentioned and other and some other, I don't remember exactly what, but yeah, lots of other things I'm sure. But yeah, I talked about, I talked with John Preskill. I remember this very vividly about the monopole problem. He wrote a very important paper, basically proposing that this was a problem. And he told me he was having a very hard time getting. past, getting it past Steve Weinberg.

Steve Weinberg. Oh, this is so speculative. Why? He almost couldn't get it published. I remember that. I remember, I remember when he, yeah, I remember when he's writing. He couldn't, almost couldn't get it published. Yeah. So that's what I mean. It didn't, it's not something you had to worry about. Yeah, yeah. But I bring it up not only because I know that you and others, and I mean, I've enjoyed the fact of watching people saying, yeah, geez, why did I, why didn't do that? But, but also, I think it points up to people that.

even an area where some of the best minds in the world are working, they're often, you know, it's worth, it doesn't mean that there isn't opportunities. And I think it's for young people to realize that, that there are, even if a lot of people are working in an area, there's often opportunities in, in direction. Well, this T violation is another one that we mentioned earlier. Yeah. Many super duper physicists, including T.D. Lee, Steve White. were many others, Ben Lee at the time, worked very, very hard to try to construct models of how T-vite, how small violation of T-symmetry arose. But it was only Kobayashi and Muscowa, who nailed it.

And it's retrospect. In retrospect, in retrospect, you knew about as another. Yeah. In retrospect, it's very, very simple. And anyone who thought about those lines would be, would have been able to figure it out pretty quickly, but just didn't, people didn't think alone those lines. And just,

so, and parity violation maybe is an even better example where the question could have been raised at any point. And it had been, we some people think, in a few lines, but. It had been in kind of a half-hearted way, but. Yeah. When it took too young, really experiments that the so-called theta-tow problem really focused

people's minds, a small number of people's minds. So that's the analog of the monopole problem, the small number of people's minds on whether you should abandon that symmetry. Anyway, okay. Okay, I think it's fascinating to see that, and that's why I want to include that moral. But I want to now talk about your broadening, your research, another area, and it also related to your life broadening. As far as I can see, I mean, you pointed out interesting enough you didn't know, didn't know anything about condensed matter physics early on.

And of course, one of the things that's interesting is you've done a lot of work in condensed matter physics, which I want to say condensed matter physics since then. I intellectually see that broadening, being associated with your moving. Yes. Moving away from Princeton to Santa Barbara, to the Institute for the Euroc Physics, Santa Barbara, which was a bold move. I mean, Princeton's a nice place to be. It's cushy.

You know, you get treated nice and, but you decide to move to a relatively nascent institute. At a university, which, while it's become much more significant, now, at the time was maybe a party school. I'm not really sure outside of the... Well, this was a national institute, a national science foundation. So it wasn't really just an outgrowth of the university. Yeah, it was a national institute that was,

that somehow they've been wily enough to the Santa Barbara people to have installed Santa Barbara. But you moved out not, I think not right away, but pretty soon after it was created. What did you not? Or within a... Yeah, yeah, yeah. Right.

Yeah, they struggled for a few years to recruit any faculty. And I was basically the first. So, you know, it's not an obvious thing that people would do. I understand. I like to. Well, you mentioned one of the big motivations before, which was I wanted to prove myself. Separate from my. Colleagues.

My esteemed colleagues. and mentors and every, you know, not that I wanted to renounce them or resent them or anything. I just wanted to have my own identity. Yeah. And so that was part of it. And also part of it was I was already feeling not that the glory days were over, but that it was time to get reinvigorated with new ideas. And I knew that at Santa Barbara,

the great strength was going to be in condensed matter of his physics. So the way of strength, if I'm not mistaken, the great strength, well, there were a few people, but Bob Shrefer was there, right? Bob Shrefer, yes, Bob Shreed. Yeah, so Bob Shrefer was that

and Doug Scalapino and Alan Heger on the experimental side. So it was a very powerful group. So you knew it was an, so I was wondering, so you did knew it was a ripe opportunity to explore a new, you know, area of physics. Absolutely. That was a big appeal for it. Okay, good.

I assume, I didn't know if it was or if it was just the idea of breaking free. And I'm sure you had a nice deal, but that's a different story. And you did. And in that context of there, you got involved in, you know, a lot of ideas. is related to, as a matter of physics, but probably the one that's captured most is the idea of anions. Yes.

And so why do you talk about that a little bit? Well, that was part of, it arose out of a questioning of the whole concept of quantum numbers. So for instance, instance, without getting too technical. Yeah. One of the, I would call it almost sacred dogmas of physics is that electric charge comes in units

that are integer multiples of the electron charge. So all particles, all observed particles have to have electric charge, which is a whole number times the charge of an electron. And there's, but we knew that models in quantum field theory, or it was discovered, I should say, we didn't know. I mean, it was discovered in the late 1970s, early 1980s, in quantum field theory, in abstract quantum field theories, and also in some very special,

materials that if you looked not at electrons in vacuum, but at particles inside materials. So what is a particle inside a material? I like to say we have, we should think of materials as worlds. If you think about them on the inside, it's a world. It's kind of, you know, just as we take our own atmosphere for granted, and we take in physics what we call empty space is actually very far from empty. It's got all kinds of structure in it, so we're inside a material. But suppose you're inside an actual material in the conventional sense,

then the localized concentrations of energy that are reproducible and travel as units, the things you would call particles inside the material could be quite different from the localized units of energy that travel along and propagate in empty space. They could have very different properties. So maybe you're going to say too. I mean, I was going to say the best example I can think of is that light becomes massive inside superconductors.

Yes, that's an excellent example. Light becomes massive in superconductors. in fact, that's the essence of superconductivity. Mathematic, if you follow out the implications of that, you get all the main properties of superconductors. And so what a big topic in Santa Barbara when I arrived was trying to exploit this idea that you could have fractional quantum numbers,

breaking up. unusual quantum numbers that are fractions of what you get in empty space. And the mechanism, the way these problems could be addressed without knowing much condensed matter physics, which was a great advantage. It's just as, you know, roughly a decade earlier, I had jumped into particle physics without any particle physics. Now, I was jumping in condens matter of physics without knowing much in the way. way of condensed matter physics. It wasn't quite as desperate, but I was still funding for sure. And, but the tools of quantum field theory, once you have this attitude that what we commonly

speak of as empty space is actually a material. Yeah. Tools you develop to understand empty space also can be taken over into the description of materials. And they give real insight into the properties and materials, especially at low temperatures when sort of the materials look like emptiness in some sense. And so I could, so I, so I, the thing that really got me started and hooked was making models in quantum field theory that showed and generalized this phenomenon that you could have objects that had fractional values of the quantities that characterize the particles that the materials are made up. electrons that are fractions of electrons as far as charge is concerned.

So then I started thinking about, okay, so we fractionalized charge. What about fractionalizing other thing, like angular momentum? And I quickly realized a way to get fractional angular momentum. It involved, well, it involves some technical tricks that involved magnetic flux and charge and anyway, and kind of exotic theories, but it could be done. It was very, very nice. But there was an issue which I didn't really think about at first, but I gave a colloquium about this at Caltech. John Presco, who keeps coming up here, was in the audience, and he asked, me. Well, what a... Okay, so you can have fractional spin. I kind of believe you, but what about

the spin statistics connection? Is there supposed to be a connection between the spin of particles and other, another basic property called the quantum statistics, which is very... And I was embarrassed because I hadn't thought about it, but I thought about it on the way home. listening to Chuck Berry on the way of drive back from Caltech to the Santa Barra, or Galita actually. And I realized the whole thing on that drive. I mean, the fact that if you have, you know, what it meant to have fractional statistics, that you get phase as one particle moves around another instead of just changing a sign you can get, well, it gets technical, the general conflict.

And the fact that in two dimensions, the magnetic flux you needed wouldn't be associated with an infinite two, but it would be associated with a point. And so it made especially good sense in two-dimensional materials. And yeah, so that was the birth of anyons for me. I found out later that. two Norwegian physicist, Lainis and Mirheim, had discussed some of these ideas, not the flux tubes, but the idea of fractional statistics and related model kind of model several years earlier, and work that was very widely ignored. But I didn't know it. But so that was that and it fit very nicely into this whole complex of ideas. about getting fractional quantum numbers

by using non-trivial topology, like vortices and things that have structure going off all the way to infinity in space. So it's, yeah, it's really pretty stuff. And then, so I was talking to, Bob Schrefer had the office next to me at the time. certainly was learning from him about different aspects of condensed matter of physics. And at that time, a very hot topic was the fractional quantum whole effect,

which had discovered fairly recently. And in the fractional quantum whole effect, the quasi-particles were fraction of electrons. at fractional charge. And when I looked into the theory, it had sort of the right field to it, it had magnetic fields and deficits of magnetic field in the region of these quasi-particles. So I got very suspicious that the quasi-particles,

in an actual, honest-to-god, material system would be anionts. And then he and I with Dan Arobos, who was his greatest student at the time, proved it. And a truly wonderful paper. And that was a subject that was widely appreciated as an elegant subject and a mathematical possibility. And even as something that almost surely occurred. in real systems. But I thought, whereas I thought the experiments to verify the basic idea would be quite

straightforward. You don't need a fancy accelerator. It's wrong. It turned out that basically because the effects are very delicate, the materials have to be pure, just really grungy kinds of problems. It was only in 20. 2020 in the spring of 2020. So almost 40 years.

That basic prediction was verified. And one reason that people faced up to these technical problems and worked very, very hard. I mean, many people tried, but it took a really determined effort. But one reason is that, it was realized that these aneons might be useful. They as, and because they, they have a kind of memory. They remember who's wound around who. And so, and so you can use them to do information processing theoretically.

And it's because it's all quantum theory. at low temperatures and under great control and the information is distributed, it's kind of robust. All these things have potential advantages as a medium for quantum computing. So money poured and experimental interests grew. And so now it's become a very big deal. Yeah, no, it's part of a merging, I want to try and come up soon because we've been gone for a while. But but but but it leads you know to I remember I remember a long time ago making the joke. You make them a joke that or and I was going to get a t-shirt that said quantum mechanic.

But we talked about the fact the wonderful thing is the idea of using quantum mechanics. What we know about quantum mechanics to design materials that do interesting things, quantum mechanics and calling the people to do that quantum mechanics. and calling the people who do that quantum mechanics. Yes. And it was a nice joke we have. But it's actually become, to some extent, the forefront of much of modern physics and engineering and technology, the idea that we're on the threshold of utilizing quantum mechanical ideas and mathematical ideas from quantum mechanics to design materials, be they metamaterials or whatever,

to do interesting things that we would never have been able to do with normal materials otherwise. And I think that's- People talk about a second quantum revolution. Yeah. I have some misgivings about that, but because it's not really revolutionary. It's quantum engineering. I guess it's not revolutionary. It's evolutionary.

But it is seizing control of the quantum world in a way that I don't think would have seemed very credible to people, even 20. years ago. Yeah, maybe in the same, I don't know if it's in the same sense, so I don't want to promote it as much, but it's similar spirit to the idea that transistors seized in some sense quantum mechanics and changed. No one would have thought of, you know, there were vacuum tubes and bells and whistles for computers and transistors, you know, led to a technology that has revolutionized the world by exploiting quantum mechanics, essentially. Yeah. And I think the essential tool for this second quantum, well, several essential tools come together,

but I would say the most essential tool is lasers. So get development of better and better quality lasers. And the other thing is, well, there are several things. The other thing is printed circuits, you know, but getting very high density, which is also you use lasers to do it. And then, well, super kind of. Well, there are a lot of developments, but almost all of them use lasers and low temperatures. It's a fascinating field of growing, of great growth, and you've been involved in.

Now, I feel you can seize control of the quantum world now. Yeah, yeah, seizing control of the quantum world is really, I think, when I talk to kids or talk to people, I think is really one of the more exciting, technological, whether it may not yield fundamentally physics per se, but technologically, it's the, it's the most. exciting new technology around. There's a lot of ferment and, no, not necessarily fundamental in the sense that it can't drive anything else, because that's the point.

You can derive it and use it as, use quantum theory as a design principle. And it works. So, and the, and we're discovering. that this theory, well, sort of like QCD is really reliable. You can push it very, very hard and have confidence that it's going to work the way that is advertised by the equations. So, and you can, and then you can be very creative. and because it's a new world.

It's a new world, exactly. And I think that's one of the things the most exciting. And it, for me, it harkens back to, again, my own, probably some of those exciting collaborations I've had in physics, have been with you. But the realization that every time there's a new kind of opening world of technology, it provides new opportunities for people who are in fundamental physics to think of using those technologies.

to learn about fundamental physics. And I'm hoping that'll continue to be the case. I know it's of excitement to you. We're using these guys from the Axion searches in a very serious way. Neutrino searches, as you know, we invoke superconductivity and various other trick technologies

and people of neutrinos, called atoms and very sensitive blocks to do tests of fundamental physics. and look for this other source of T violation. We know it's less than a part in 10 billion, but maybe it's apart in 100 billion. It would be very interesting to know that number. It's sort of comparable in interest maybe to the proton decay.

Yeah, to knowing the number for the... Because once you know, technically, once you know the electric dipolement of one fundamental system, which is a manifestation of this time reversal violation, you can examine it in other systems and get a pattern and see what the underlying fundamental interactions are. I mean, you can try to infer what the underlying fundamental interactions are. So it would open up a new window into,

beyond the standard model physics. That's right. We're looking for new windows. So I must say to me, it's one of the most exciting ways of thinking. Personally, to the extent that I think about physics now, it's thinking about that, about using new ideas like that. And I know that when we've had a wonderful, a lot of fun over 40 years doing that, I hope to be able to maybe use some more with you on that because I think it's exciting. And it allows me to sort of get to the wrap-up part, which is,

I don't want to call you a grand old man because I suggest you're old. but um and that was like i'm old i am old by the calendar but anyway but i do want to talk about the state of the state of physics and state of science the last five or ten minutes which is you know reflections on exciting areas for young people and and i think it's fair to say based on our conversations and you know to be honest for you know on your own own areas of work that you know the excitement of the 1980s or 1970s of the of sort of going beyond the standard model and stuff that that may not be that well where is the you know there's been a big disappointment that we haven't seen anything yet and that forces us to something beyond the standard model it's been 40 years and it's a it's hugely

disappointing if you're a certainly a young person you're trying to get beyond the standard model it's hugely disappointing that's right yeah yeah if you want to move beyond and trying in there we know we need to have physics beyond the standard model but we need to experiments. And of course, it produces sensory deprivation and you get thousands of thousands of hallucinatory papers all proposing their own mechanism and nothing to drive us between them. But what's his data? Where do you think that things are most exciting? And we've talked about it. But first of all, I assume you think physics is healthy in spite of what people, some people might say what might say. But, yeah, well, physics as a whole is multifaceted and as a function of time.

what's vibrant, what areas are making progress changes. It's very clear by now in retrospect that the 1970s were a golden age for fundamental physics, you know, setting up the basic laws of most of the interaction, most of the fundamental forces of nature. And understanding that quantum field theory really, works and but it's rich and subtle in its description of the world and then applying that to cosmology and we didn't talk about it very much but the ability to probe the early universe experimentally. It's just amazing. Improved by leaps and bounds and again in many ways the simplest ideas worked.

people have been struggling to get beyond a standard model of cosmology and with very mixed success. And the analog of proton decay maybe is a gravitational wave background from the early universe. That hasn't been materialized either. And non-Galcian, there are various things that people hope to get beyond standard model that haven't materialized. We haven't seen them. And basically, so we had these wonderful developments in fundamental physics and fundamental

cosmology in the 70s and 80s, which in a way were both a blessing and a curse. I mean, the blessing is that they're very, very successful. And the curse is also that they're very successful. It's hard to do better. Okay. So maybe you don't need to do better for, certainly for practical purposes, you almost surely don't need to do better.

But if, you know, if, if you want to improve the fundamental understanding of nature, which has been one of the traditional goals of physics and a very attractive goal for bright young people, it's been disappointing and difficult. You're sort of reduced to thinking about problems of principle and, you know, things like quantum gravity where you don't

have any really relevant data. And so it's difficult to make progress, also difficult to know if you're making progress. Yeah, exactly. You don't get any feedback. You don't have a dialogue with nature. And but on the other hand, now we have really reliable theories that you can, can try to use creatively. There are great challenges to designing new technologies that do useful things, but also do things that we couldn't do before in probing fundamentals. So looking, looking for small effects that are outside the standard model, looking, figuring out what the dark matter is, whether really is it axions or some, that's sort of. That's sort of. That's sort of, Certainly, I think now is the leading hypothesis after many years of being a voice in the wilderness.

The converts are all around. And the, you know, proton decay. There are a lot of things that could happen, and I hope they do. But the old central thrust of building big machines and, having surprises come out at you just because it's at higher energies, that hasn't really worked out spectacularly well. You got the Higgs particle, but that's okay. You knew what to look for.

That's still 1970s physics. And nothing else, just the minimal thing. So. Okay, let me change. What you can see visible progress is in quantum technology, quantum information. Deep profile, the quest to build a useful quantum computer, sort of designing new materials, maybe exploiting machine learning to solve difficult problems. Like, I mean, one of my favorite problems is to bring the theory of neutron stars

to the same level as the theory of ordinary stars. understand. That's a giant nuclei. We have the equations for it, and gravitational wave experiments are going to open up new windows into their structure, but theory isn't ready for it. Yeah. Okay. Well, okay, look, I think we're looking for that, you know, we'll get to, we'll end with

maybe what next, but, but I want to, you know, there's a lot we're not going to be able to talk about they want to talk about. But I will want to throw you some sort of one word, one sentence answers or your opinions on on things like, let's take quantum computing, which you mentioned. Optimistic, pessimistic, what do you think? I mean, I think it's been Harry with that a lot of hype, but there's a lot of great developments. I'm a long, I'm long term optimistic, but long term might be 100 years. Okay.

They'll be able to do meaningful problems that for classical computers are inaccessible, but silicon technology is really, really impressive. Moore's Law has been working for a long time. It's not going to be easy to do better. And I think, you know, I unfortunately, I think expectations have been raised too hard for short-term success. That's- Well, okay. Now, an area where expectations or dis-expectations have been raised fairly high is AI. You know, their doom and gloom, the world ending.

And so your thoughts on that? I'm looking forward to having Silicon friends. Me too. I'm worried about the world ending then as... I'm much more worried about natural stupidity than artificial intelligence. Exactly. Although, you know, they do overlap. I'm very worried about military applications of powerful artificial minds,

which sort of continuously... connect to the idea of a doomsday machine. You have something that is outside of human control and just does its thing. If it's not very, very carefully designed, well, it'll do what it's designed to do whether you're designed carefully or not. And so that's, that's,

That's really... It is a worry about... I mean, I think that's... I agree with you. The military application of AI are the biggest concern because of the inability to have not just human intervention, because I'm not sure he wins so much better, but the speed at which decisions be made. Yeah.

And they're forced to be... Yeah. I mean, the way I like to put it is the following. We're going to make... These are very powerful minds. There are new kinds of minds. And we can, they have some superhuman strengths, but they also have some subhuman. and weaknesses, they're different.

But for sure, very powerful in some ways. And you're teaching them. You're teaching them as new kinds of minds. Now, if you're teaching them to be military minds, then sort of almost by definition, they need to be paranoid. They have to worry about threats, and they have to be aggressive. They have to go out and if there are threats, if they're dangers, they have to address them powerfully.

So you're training a powerful mind that's a paranoid, aggressive, paranoid personality. It's really scary. That part is scary, especially when you, and you know, it's sobering to think that you hope that the people that are, if they're, working in Belterian are the same ones who produced the Google machine that, you know, showed George Washington to be a black woman. And the AI, that aspect. I think, I think it demonstrates that, you know, I'm not as worried as some, but it demonstrates the need to be careful and think.

But I agree with you. I, I, I, I think we both said once. For me, I am interested in know eventually if AI, you know, what physics questions are interest AI and to learn from them. Yeah, they'll, you know, we already have some experience with this, that machine learning technologies and just the ability to do massive number crunching calculations changes the kind of questions you can ask. It's affected UCD very much.

Yeah. If you want to calculate the masses of strongly interacting particles, accurately, you feed the equations to a computer and it gives you the answers. There's no other way that's remotely competitive. And so, okay, you may say that doesn't give me a lot of insight or as well. Too bad. I was going to talk more about Lattis BCD, but I have time. But two last things. One quick question, space travel. There's a lot of people who seem to think like Elon Musk that we should be going sending people to Mars and it's a panacea. What do you think about human space expression in the near term versus the long-far term?

I think it's dopey in the near term and probably pretty dopey in the long term also. Human bodies are not designed to thrive outside a very narrow range of conditions that you find here on Earth. Now, you can imagine cyborgs. Yeah, or little teeny computer chips. Or you can imagine things that are not human bodies, but are in communication with human minds going out there. And that could make a lot of sense and would be fun. You know, explore. People like to do astronomy and cosmology.

And it might also. be important for the long-term viability of mind in the universe if Earth goes sour as the result of climate change or nuclear war or something. But I don't think the idea of transported human bodies elsewhere is at all realistic or viable. It's anything that's making it. And when you say that in contact with human minds, I think ultimately that may not be necessary either. I mean, the idea that, you know, the future, it's just mass as enemy space travel, I imagine, small, independent, not, you know, independently operating, you know, not cyborgs, but maybe small, small little computer chips that eventually can maybe build something if they need to

at some other. Yeah. Yeah. Yeah. Well, that's communicate by radio. There's all kinds of things you could imagine. So collective minds, emergent minds. And it's probably one of the main reasons. I think just sending out sensors out there without having to communicate with anything, that doesn't inspire me very much either. So some kind of mind I would like to. It doesn't have to be a human mind.

It doesn't have to be a human mind. No, not at all. I think in the long one, it's not going to be. And that's why, you know, that's the other thing about, Right. Fascination with aliens is that they're probably, you know, it's not going to be beings. It's not going to be biological or not beings, actually ever. I agree with you. Probably not. It would, you know, even, humans are a remarkable design and a remarkable phenomenon. And I think very much worth continuing and preserving. But I don't think they're the last word in mind of me. universe. Thank you. That's a really good way I'm putting in, I think, that, yeah, exactly. And, you know, I like to compare us to Archaeopteryx following the science fiction author

Olaf Stapled. And, you know, Archaeopteryx was a beautiful creature and it was a very bold explorer of new possibilities who were interacting with the world. But it wasn't the last word in flight. It wasn't exactly. The fact that it got outdone by its

descendants, by no means diminishes what it meant to be an archaeoptery. I also find, I don't know if you find, but people are amazed when I just sent out, I just tweeted a picture from the rovers. I love doing it. but I find it more almost more romantic and more,

I almost feel more tied to Mars when I get rover images than if it was an astronaut. Because this is part of the rover and there it is alone. It doesn't need boo, doesn't need sex, doesn't need companions, it's just out there on its own. And it's an integral part of it and it's showing me what is experiencing. So the fact that a person doesn't mean anything to me. And when I, when I, when I, when I, right, I think I agree with that sentiment. I think of it as an expansion of the human sensorium

doesn't even belong to any individual. So that's wonderful. It is wonderful. And as I say, you can send her over to Mars for the cost of making a movie about sending Bruce Willis to Mars. But, okay, last question, I guess, for the moment, because it relates to what is for some people's frontier physics. It's an area you and I've worked.

on together and independently, which is quantum gravity, which is, you know, it's, I mean, you're, I first learned this from you, that a theory of quantum gravity is not a theory of everything. It's a theory of very little in the sense it's, it'll be useful for understanding the beginning of the universe and the ultimate state of black holes. But other than that, it's kind of irrelevant. But those are the obvious applications. There might be remote applications of a deep understanding that would be very difficult to foresee. Like, I mean, like in general theory, the perihelian of Mercury, who knew that would come from a better, much more profound

than what gravity is all about. Or, you know, in the case of axions, who knew that that would be connected to the dark matter? You never know. It's true. You never know, so you think. You never know. But the great hope of string theory, of course,

was that by thinking about the necessity of a consistent quantum theory of gravity, you would be led into insights and maybe even a unique theory about everything, getting beyond the standard model and relieving its shortcomings and so forth. I think it's fair to say that hasn't delivered. It's fair to say it hasn't delivered. But there are two, you know, I'm very pleased of two papers we wrote on that, but one which was the, I think the ultimate Godunken experiment, which was scattering a causing string off a black hole.

But the other one. Oh, yes. Well, that's beautiful work, I must say. And it's a Godinken experiment as far as scattering a cosmic stream off a black hole, but very much in the spirit that led to anyons. Yes. Very much in that spirit. In fact, some of the same ideas and objects occur.

The mathematical ideas there, I think, are much more robust than that. Absolutely. Yeah. That's an example of, you know, it hasn't yet born spectacular food, but that's an example of where you might imagine that, thinking hard about fundamental questions of quantum gravity would have unexpected. Exactly. It was a lovely, it was a surprising piece of work. And I think also the realization that, that, in our more recent paper of ours, but, but, you know, there may be a way to, there's a big

question and people like a tuft and, you know, wouldn't physicists seem that some of physicists think, maybe, maybe, you know, quantum mechanics isn't fundamental and maybe it'll succumb. And I'm very pleased to know that, you know, that we, that it's possible to show. It's possible to imagine an experiment to result, which might come even in our lifetime, perhaps, that will demonstrate that gravity is a quantum theory. And I think that's, I think that's fast. I think we pointed out a particular phenomenon that would be very, very difficult to understand, you know, essentially impossible to understand without taking into account that gravity is a quantum theory.

but there may be others. I'm actually actively thinking now about others. Okay, that's good. And this leads me then, you know, what's the prognosis? I mean, thinking about quantum gravity, produced string theory and a lot of talk and a lot of good physics, a lot of good mathematics and some interesting physics. What do you see as the prognosis?

I mean, you know, do you see, do you think we have to be in the next 100 years? I'm very optimistic that I don't know how long it'll take, but no, tens of years, not thousands, hundreds or thousands of years, and maybe just a few years, to find domains or phenomena in which the fact that you need to quantize the gravitational field. is manifest. I think there are all kinds of conceptual reasons to think that you must quantify the gravitational field, but there's no real crisp experimental demonstration, I would say, similar to tests of the idea that there are photons. Yeah, that fruitful thing that correlates lots of data. But I think that might come from a carefully focused experimental program probing some aspects of gravitational waves. I think gravitational waves or some other aspect. I agree.

Although, to be fair, if we find out that gravity is quantum theory, it's still maybe a long time before we know what is a quantum degree. Well, I was going to say that. I mean, so at a technical level, this would be at the level of quantum mechanics. as opposed to quantum field theory of gravity, which is, would it, well, it's, it's a little technical to make the exact distinction. But there are many aspects of quantizing gravity that you can work out without having a profound understanding of how gravity works at extremely high. energies and features, which that would be the deep theory of quantum gravity. And that's what string theory is supposed to address. It's not, don't need string theory to quantize Einstein's theory

in the near flat space limit. And so get hawking radiation and whole number. And get gravitons. And get gravitons. All that is not. But we may not understand. What do you think we'll eventually understand whether black holes evaporate to nothing or is that kind of mystery going to remain a long time in the information associated with that? Well, I think there might be a, there might be a theoretical consensus that emerges among a large part of the theoretical community about the answer, but will it have empirical content? Will it actually correspond to any kind of phenomenon you can point to? I don't see that emerging any time.

And it's interesting that you say that because, of course, a large part of the community is doing just that. So it's kind of interesting to see how much effort is being devoted to somebody. Well, there's a whole philosophical movement. which I really detest, called post-emperical physics. Yeah, yeah. You say, okay, physics is not about describing the empirical world. Okay, well, the physics I knew was supposed to be not describing the empirical world.

You're describing something else. Yeah. Well, I think, look, the point is there's a lot of physics of the empirical world remaining be done, and you're so excited about it, and it's wonderful. And I think there's room for people thinking about those questions. But I am disturbed by how many bright young people are investing their scientific careers in things that, well, I want to be careful what I say here, but certainly are on the verge of being sterile. they'll leave it anywhere. It's maybe a property of us getting older to think that, but it may not be.

But I agree. But on the other hand, there's an excitement and there's much to do. And I like the fact that you are always still excited about what remains be done. It's been a joy and one of my great joys to be a part of that with you for a while. And I really hope, I'm really pleased you took the time here. So everyone can see not just a perspective of the physics zone and that you've been involved in in the last 50s. years or so, but where physics is going and what physics minds think, and what a great physics mind thinks like. And it's been a pleasure. Our two hours became four hours, but it's been every,

every moment. I delight. I enjoyed it too. All right. Thanks a lot, Lawrence. Good to talk to you. It's always good to talk to you, Frank. Thanks. I hope you enjoyed today's conversation. This podcast is produced by the Origins Project Foundation, a non-profit organization whose goal is to enrich your perspective of your place in the cosmos by providing access to the people who are driving the future of society in the 21st century and to the ideas that are changing our understanding of ourselves and our world. To learn more, please visit Originsprojectfoundation.org.