Feb 12, 2023Liked by Sven Schnieders

Nice write up, although I have a different view of SA. He may be critical of some QC papers, but he also boosted Google's Quantum Supremacy, which was basically a snow job. Despite the paper's claim of solving a "computational task", the quantum gates were unique, device-specific, calibrated, non-standard unitary transformations. A second copy of the device would have had different calibrations and would have reached different results. If we insist that "computational tasks" are device-independent, the study failed.

SA quote: (1) It’s actually really, really hard to invent a model of correlated noise that kills scalable QC—not merely in the weak sense of killing some specific fault-tolerance scheme, but in the strong sense that there’s then a polynomial-time classical simulation of your system. Gil Kalai, an excellent mathematician, has been trying to do this for 15 years, but as far as I can tell has completely failed.

(2) If QC-killing correlated noise existed, and if it were impossible to get around it for fundamental physics reasons (as opposed to it merely being a hard engineering problem), then that itself would be a huge new discovery about physics. It would mean there was something of enormous importance we hadn’t understood about quantum mechanics itself, something that allows a “polynomial-time hidden variable theory.” Nobel Prizes would be in order. I and most of my colleagues would eagerly accept that as an outcome from QC research!


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May 19, 2023Liked by Sven Schnieders

Thanks for a good article. When I was completing my physics degree ~10 years ago, I remember looking into QCs (they were also major hype back then) and learning how the qubits are so easily disturbed. I guessed QCs were not imminent, and that still seems to be the case.

You make a good point about shorting science hypes. I have found this to be a lucrative pond to fish in. VCs have rushed worthless science projects to public markets for exit liquidity. Some can be easily disproven with simple back of the envelope math.

For QCs, I would recommend looking at $IONQ, a hilarious hype led by an embarrassingly clueless CEO.

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Feb 11, 2023Liked by Sven Schnieders

Really interesting! loved it.

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Thanks for this. I suspect the encryption-breaking FUD will come, therefore I appreciate your feet on the ground thoughts on the subject.

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