[GilKalai]

In the past five years I participated in a project (with Yosi Rinott and Tomer Shoham) to carefully examine the Google's 2019 "supremacy" claim. A short introduction to our work is described here: https://gilkalai.wordpress.com/2024/12/09/the-case-against-g.... We found in that experiment statistically unreasonable predictions (predictions that were "too good to be true") indicating methodological flaws. We also found evidence of undocumented global optimization in the calibration process.

In view of these and other findings my conclusion is that Google Quantum AI’s claims (including published ones) should be approached with caution, particularly those of an extraordinary nature. These claims may stem from significant methodological errors and, as such, may reflect the researchers’ expectations more than objective scientific reality.

[janpmz]

I've heared claims before that quantum computers are not real. But I didn't understand it. Can anybody explain the reasoning behind the criticism? Are they just simulated?

[sgt101]

I think that this is now a very fringe position - the accumulation of reported evidence is such that if folks were/are fooling themselves it would now be a case of an entire community conspiring to keep things quiet. I mean, it's not impossible that could happen, but I think it would be extraordinary.

On the other hand the question is what does "real QC" mean? The current QC's perform very limited and small computations, they lack things like quantum memory. The large versions are extremely impractical to use in the sense that they run for 1000ths of a second and take many hours to setup for a run. But that doesn't mean that the physical effects that they use/capture aren't real.

Just a long long way from practical.

[Rhapso]

So the basics:

- quantum physics are real, this isn't about debating that. The theory underpinning quantum computing is real.

- quantum annealing is theoretically real, but not the same "breakthrough" that a quantum computer would be. Z-wave and google have made these.

- All benchmark computations have been about simulating a smaller quantum computer or annealer. which these systems can do faster than a brute force classical search. These are literally the only situation where "quantum supremacy" exists.

- There is literally no claim of "productive" computation being made by a quantum computer. Only simulations of our assumptions about quantum systems.

- The critical gap is "quantum error correction", proof that they can use many error prone physical qubits to simulate a smaller system with lower error. There isn't proof yet that is actually possible.

This result they are claiming, is they have "critical error correction" is the single most groundbreaking result we could have in quantum computing. Their evidence does not satisfy the burden of proof. They also only claim to have 1 qubit, which is intrinsically useless, and doesn't examine the costs of simulating multiple interacting qubits.

[whoitwas]

I'm skeptical only because they have AI in the name.

[qnleigh]

What experimental data would you need to see to change your mind? Either from Google or from another player?