Spin qubits could scale quantum computing using the same semiconductor fabrication lines that print 50 billion transistors on an Nvidia chip. No new manufacturing paradigm required.

Brandon Severin, Oxford PhD and founder of Conductor Quantum, joins Mark and Jeremy to explain why that matters. 

You need hundreds of reliable qubits for meaningful quantum computation. The industry has dozens. Spin qubits, built from modified transistors, controlled by classical voltages, no lasers, no vacuum, may be the most practical path to millions.

This episode covers:

• Why qubit fidelity and coherence time determine what a quantum computer can actually do
• How AI automates the calibration problem that makes human-controlled quantum scaling impossible - "you can't have a billion Brandons"
• Why trapped ions vs spin qubits is the wrong debate
• What Google's quantum algorithm result actually proved, and why it matters
• Why the physicists who understand semiconductor manufacturing may unlock use cases pure quantum researchers never reach
• The two camps dividing the quantum industry: build one qubit at a time, or build for a million

Also: quantum startup culture vs the AI boom, Brandon's Y Combinator experience, and why scaling quantum looks more like building a rocket ship than climbing a ladder.

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Brandon Severin: https://www.conductorquantum.com/

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Timestamps

(00:00) Introduction: spin qubits and the quantum scaling problem

(03:47) Trapped ions vs spin qubits: fidelity, coherence, and tradeoffs

(06:14) What qubit fidelity means and why it determines scaling limits

(08:25) What is a spin qubit? Building from the transistor up

(11:06) Semiconductor fabrication as quantum computing's manufacturing advantage

(15:00) The quantum circus: superposition, measurement, Schrödinger's cat

(17:17) Shuttling qubits — moving electrons across a chip

(20:33) How AI automates quantum calibration (the control problem)

(25:00) Quantum scaling vs AI scaling: the GPU parallel

(29:08) Quantum startup culture and the AI generation gap

(32:59) Building for a million qubits — rocket ships vs ladders

(36:52) Why quantum is taking so long: talent, concentration, and meaning

(39:43) What seems impossible now that will be routine in 20 years