So, "verifiable" here means "we ran it twice and got the same result"?
> Quantum verifiability means the result can be repeated on our quantum computer — or any other of the same caliber — to get the same answer, confirming the result.
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> Quantum verifiability means the result can be repeated on our quantum computer — or any other of the same caliber — to get the same answer, confirming the result.
I think what they are trying to do is to contrast these to previous quantum advantage experiments in the following sense.
The previous experiments involve sampling from some distribution, which is believed to be classically hard. However, it is a non-trivial question whether you succeed or fail in this task. Having perfect sampler from the same distribution won't allow you to easily verify the samples.
On the other hand these experiments involve measuring some observable, i.e., the output is just a number and you could compare it to the value obtained in a different way (one a different or same computer or even some analog experimental system).
Note that these observables are expectation values of the samples, but in the previous experiments since the circuits are random, all the expectation values are very close to zero and it is impossible to actually resolve them from the experiment.
Disclaimer: this is my speculation about what they mean because they didn't explain it anywhere from what I can see.