[meltyness]

I think his model of the situation is short-sighted, to say nothing of the callbacks to that management principle involving transistors.

If you're thinking that the whole purpose of QC will be quickly subsumed by wide algorithms with superpolynomial speedup, you might be missing the point. It's about how computers are built, not about stuffing one specific abstraction into another. If suddenly we discover we can build a machine that can generate random numbers a quadrillion times faster than any current hardware design, that's a new space in computation.

I mean consider how widely deployed the parallelism construct is now, and that Amdahl's law was elucidated in the 60's.

Parallelism was just one degree of freedom for us to climb the S-curve on, quantum computing seems to provide essentially a continuum of them.

[sweezyjeezy]

I think most people, including the author, would agree QC should be funded for fundamental research reasons. But that is clearly not the way it is being pitched to VC. Right now there is no clear use-case, that's what I felt he was warning against. If nothing materialises soon, he's probably correct to say this is a bubble.

[marcosdumay]

> Right now there is no clear use-case

Why people keep repeating that? You mean that if somebody creates a machine that can simulate chemistry and materials science in polynomial time, nobody would use it? That's crazy.

[sweezyjeezy]

The key word being 'if' - cited research from the FT article that disclaims this: https://arxiv.org/pdf/2208.02199.pdf

I have no expertise in QC/chemistry so I can't make a judgement other than to say it doesn't seem universally agreed that QC will be a silver bullet here.

[marcosdumay]

That's quite similar to claiming that quantum computers won't change anything for RSA cryptography, because we never had any proof that integer factorization can't be done in polynomial time on a classical computer.

It's true, in some sense.

[sweezyjeezy]

The paper also shows that the proposed QC strategy for calculating energy levels - where you start with a guess and then optimise - may not lead to exponential speedup on a large class of important chemicals, because just coming up with an appropriate initial guess has no polynomial time algorithm at present. So it's not clear for what class of chemicals this would even theoretically become a tractable calculation.

[marcosdumay]

Yes, that applies to the chemicals that we currently have very good heuristics to guide the optimization, in a process that is usually validated empirically afterwards because of it's not perfect reliability.

At the same time, it doesn't go to lengths to discuss how the heuristics needed for the quantum computer are much more general and self-validating (if it converges, it converges).

But then, nobody knows if the classical algorithms will improve enough so that when we actually get quantum computers they will still be needed. That's the article's point... What is not different from the RSA one from my post.

[meltyness]

I figure it's more like a standoff between these shops. Just consider that historically, no one would want to build ENIAC, everyone would want to design the solid-state transistor.