Technology, Connected - The Quantum Circus

Episode Date: November 8, 2025

Brandon Severin (CEO, Conductor Quantum) explains spin qubits and the complex nature of quantum computing. With a lion.Take one electron. Put it in a magnetic field. It acts like a tiny compass needle with two orientations—spin-up and spin-down.Those are your 0 and 1.Isolate that electron on a gated silicon device. Hit it with precise pulses. You can flip, hold, and combine those states (superposition). That's quantum computing.The advantage: Spin qubits use the same fabrication tech as classical transistors.Modern NVIDIA and Apple chips have tens of billions of transistors. The same infrastructure could eventually produce comparable numbers of spin qubits. Each qubit is just one electron you can address and control.We talk about:- How spin-up and spin-down create quantum states- Why silicon fabrication gives spin qubits massive scaling potential- How you flip electron spins with precise pulses- What superposition means at the electron level- Why spin qubits could scale faster than superconducting or trapped ion systems- The challenge: controlling billions of individual electrons with precisionThe promise: If we can print 50 billion transistors on a chip, we could eventually print 50 billion qubits.That's the quantum leap spin qubits are betting on.---Guest: Brandon Severin, CEO Conductor QuantumTopics: Spin qubits, quantum computing, electrons, silicon fabrication, superposition, scalingWatch on YouTube: https://www.youtube.com/watch?v=9LeN3VBvG0o&t=1sCheers,Mark & Jeremy--Other ways to connect with us:⁠Listen to every podcast⁠Follow us on ⁠Instagram⁠Follow us on ⁠X⁠Follow Mark on ⁠LinkedIn⁠Follow Jeremy on ⁠LinkedIn⁠Read our ⁠Substack⁠Email: [e-mail]

What is a spin-cubit, I think, is the question. There's two ways to approach this. There's the very bottom, bottom-up way, where you start with the physical spin-cubit. Or there's a top-down way, which is you start with a silicon chip. Let's start with the bottom-up way, because that's the fundamental question. What is a spin-cubit? So a spin-cubit is an electron-orientated in a magnetic field. And you can view that electron similar to this NMR nuclear magnetic resonance.

that electron behaves as like a tiny bar magnet. Similar to the magnets or a compass needle on planet Earth, it wants to align with the magnetic field, right? Your compass needle wants to point most. It's kind of similar feel with your electron. It either wants to be spin pointing up or spin pointing down. And up, let's say, align with the magnetic field or down against it. And those are your two quantum states.

Those are your two bits. Spin up, spin down. Zero, one. Now the whole part is, well, okay, great. And I think, like, arguably, you could say this is probably like one of the nature's most fundamental cuba. You can't get smaller than an electron sphinximate. Then, halfway, okay, how do I isolate individual electron? Good luck.

And that's where the silicon comes in. That's where we come in as a company, which is you look at the transistors on your desk, the transistors in your phone. Those are basically tiny, tiny switches. You've got like 50 billion transistors in your pocket right now that allow you to control billions of electrons flowing across them per second. You know, and that's on or off. The current's flowing. The electrons are flowing.

Transistors on. Current's not flowing. Electrons stop flowing. Off. And it's like, okay, can I turn that into a quantum bit? I've got billions of electrons flowing, but I only need one electron. And the genius part of SpringCubits is, If I just slightly modify my transistor to give me a bit more control over the flow of electrons

and still keep the same semiconductor process that prints trillions of these transistors every day, but just say, look, let's just kind of tune this transistor, kind of like fast and furious, you know, you tune up a car, out a bit of a nose or whatever. Yeah, yeah, yeah, but very small, very small. Can I start isolating individual electrons? The answer is literally, yeah, you can. And the trick is, you can. is basically a transistor works on having what's known as a gate electrode.

It gates the flow of electrons going from one side of the transistor to the other. If you add a few more gates, you can basically start to isolate electrons between these gates. It's all between, physically underneath these gates. All of these gates is all controlled by standard voltages, classical electronics. So no lasers, no vacuum. Same way your electronics work now. And if you finally tune the voltages you applied to those gates, you can isolate an electron.

You can make it jump to the left, jump to the right. You can have it sit there for, you know, what seems like an eternity in the quantum world. In reality, it's not that long. I mean, we're talking like milliseconds. But because going back to, you know, your point on operation speed, you can get that electron to flip between state zero and one on the order of nanoseconds.

Your gate speed is on the other nanosex. So if you have mini seconds of your electron living in this quantum world that you've built for it, you know, you can do thousands and thousands of operations within that time. And that's your spinky bit. All right. So what did we just watch right there? We watched Thinking on Paper, bite-sized, a shot of technological tequila to your prefrontal cortex. It's just a taster, a smorgasbord, of what awaits you with the full thinking on paper interviews. There really is nothing to like it out there at the moment connecting the dots of all these technologies.

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