I'm sure it's faster than simulation, but in what sense is this a computer and in what sense is that a computation?
Google claims to have proved its supremacy with new quantum computer
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Re: Google claims to have proved its supremacy with new quantum computer
#82Earlier quoted context omitted.
Not a dumb question! There is a great video by the mathematician Richard Borcherds on this exact objection to current examples of quantum supremacy. https://www.youtube.com/watch?v=sFhhQRxWTIM
I love this video, thanks for sharing it. I'm watching it right now and I think I'm going to refer to his "teapot supremacy" from now on.
I declare AlexCoventry supremacy. No one can compute AlexCoventry better than I can. :-)
Re: Google claims to have proved its supremacy with new quantum computer
#83The cited paper[1] references "random circuit sampling" which is defined in [2] which then gets so heavy into abstract math, and I give up. Can someone explain this in terms an EE or programmer can understand? [1] https://arxiv.org/abs/2304.11119 [2] https://arxiv.org/abs/2007.07872
> The theoretical basis for these experiments depends on sampling the output distributions of random quantum circuits; unfortunately, understanding how this theoretical basis can be used to define quantum supremacy is an extremely difficult task. Anyone attempting to understand how this sampling task relates to quantum supremacy must study concepts from random matrix theory, mathematical analysis, quantum chaos, comp…
> This might be a case of a rabbit you do not want to chase.
I'm sure the researchers will all collectively realize this, if it were to be the case, and disregard their 12 year academic journey with their great salaries in favor of research into more important topics like world hunger, renewable energy, etc.
I'm so sure that the percentage of sureness is an imaginary, quantum-entangled value between -7 and 13 billion percent.
Re: Google claims to have proved its supremacy with new quantum computer
#84Dumb question: Say I have a wooden stick and I break it in half in less than a second. Assume a computer would need several minutes to simulate everything that would've happened in the stick. I clearly got the output faster than a computer (and with more precision), so does this imply I'm doing anything particularly fascinating? I assume the same scenario is possible to concoct for a quantum computer. I assume it wou…
I think a more fair comparison would be that you know how to break the wooden stick so that you end up with one piece measuring exactly 152 mm and you can repeat the feat every single time with other wooden sticks of different dimensions crafted from different trees under different environmental conditions.
Re: Google claims to have proved its supremacy with new quantum computer
#85The ability to entangle particles feels like a really amazing new capability. (New in the last 100 years anyway). Like it’s a brand new kind of substance that has never been made before. Everything in all of history has been built out of boring old atoms, not these fancy new entangled things. Even if quantum computers turn out not to be able to solve interesting problems, I wonder if computers are the only thing we c…
Electric space heaters? That's crypto's most practical application.
Crypto makes extremely expensive space heaters.
On the positive side, they are just as efficient as regular space heaters in producing heat from electricity.
Re: Google claims to have proved its supremacy with new quantum computer
#86I don't remember the details, but the reason the 2019 paper was challenged was because Google did not take into account quantum simulation optimization techniques when estimating how long the computation would run on classical computers. I wouldn't be surprised if there's a similar situation here, where unconsidered optimizations prevent this from being quantum advantage.
The main challenge for the Google quantum supremacy result was that calling it a computer or what it does a computation never made any sense.
Re: Google claims to have proved its supremacy with new quantum computer
#87Earlier quoted context omitted.
There's a fundamental question as to whether or not it's exponentially difficult to add additional qubits. If each marginal qubit is 5% more difficult to add as the previous one the task would be essentially impossible - and even if it wasn't impossible it would turn out to basically be cheating (in that you would be doing exponential work via either the quantum computing route or the conventional route).
Note: that there is good physical reasons why the cost of QC may grow exponentially with qbits. Refrigeration is exponentially inefficient as T=>0 and the gap of a quantum system which sets the temperature you must cool to shrinks as you couple new degrees of freedom. This dynamic has been the basic reason for the sub exponential progress in the area (despite exponential expenditure)
Not for photonic quantum computing. Only detectors require cooling, and it is possible to build adequately sized quantum computers with constant number of detectors using loop based architectures.
Even more realistic architectures are very very cost effective on the number of components https://quantumfrontiers.com/2023/06/21/what-is-the-logical-...
Re: Google claims to have proved its supremacy with new quantum computer
#88Dumb question: Say I have a wooden stick and I break it in half in less than a second. Assume a computer would need several minutes to simulate everything that would've happened in the stick. I clearly got the output faster than a computer (and with more precision), so does this imply I'm doing anything particularly fascinating? I assume the same scenario is possible to concoct for a quantum computer. I assume it wou…
You're not modeling or predicting anything though. That's like saying "what if I built a bridge that failed on the first day? A computer would need several days to calculate all the forces that led to the failure, but my bridge failed just fine without any computer help".
Well... yes. But try building a bridge that doesn't break.
Or to keep with your scenario, try to predict exactly where and how your stick will break before you break it. You can't.
Re: Google claims to have proved its supremacy with new quantum computer
#89Dumb question: Say I have a wooden stick and I break it in half in less than a second. Assume a computer would need several minutes to simulate everything that would've happened in the stick. I clearly got the output faster than a computer (and with more precision), so does this imply I'm doing anything particularly fascinating? I assume the same scenario is possible to concoct for a quantum computer. I assume it wou…
One would be the direction of entropy. Breaking the stick is not "particularly fascinating" because you're going in the direction of increasing entropy. However, _putting it back together_ is. In the simulation it takes no more effort to go one way or the other, while you probably cannot put the stick back together no matter how hard you tried. A quantum question that is "interesting" would also be similar to finding…
I really love this comment -- it "feels" like the right criterion -- but I guess I'm wondering what criteria (if any) researchers actually use right now. Do they have any criteria for this?
Re: Google claims to have proved its supremacy with new quantum computer
#90Earlier quoted context omitted.
What are these capabilities of which you speak? Or have i missed the sarcasm
Well, generate reality for one. It's not a trivial detail, but it tends to be dismissed or taken for granted (or downvoted lol). Someone may venture into this territory some day, and perhaps that someone will find some travelling companions to make the journey more exciting and productive....time will tell!
Generate reality? I am not crystal clear on what you're talking about. Quantum computers are still just computers, not magical replicators from Star Trek.