On the Leaked Google/NASA Quantum Supremacy Paper
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As the person says, they have been out of the field. For better or for worse, this is the term the field settled on years ago to mean showing that a quantum computer can sample from the Porter-Thomas distribution more quickly than a classical computer, “beyond reasonable doubt.” (What I mean by the last bit is that it must be an empirical demonstration that matches the very well established theory.)
It’s maybe worth repeating: “Quantum supremacy” isn’t some gimmick made up by the authors of this paper. It was used as early as 2012 [0] by John Preskill, a well known scientist in the field. It has well-defined meaning in the research community: a specific experimental verification of a mathematical result which shows plausible rejection of the extended Church-Turing thesis.
This result may not seem like much to the average reader, but—provided it passes the muster of peer review—it’s a huge step of progress in the development of quantum computers.
Interference is also NOT why there are are no error corrected quantum computers. The reason there are no error corrected quantum computers is because we need way (way way) many more physical qubits, and they would need to be of better quality (less decoherence).
However, the second bit you said is true, even after correcting the term.
I get that the term quantum supremacy was coined long ago, by people who were most likely not looking at the event with the degree of granularity that our present technologies require. It's just unfortunate that what made sense on a macro level becomes illogical when looking at the minutiae.
Although I suppose this IS fitting in a way, since it parallels quantum mechanics itself.
There are no naming committees. Names pop up largely by accident. This is true for all fields. Heck the entire field "artificial intelligence" is named in a way that causes no end of incorrect beliefs among laypeople.
The solution is better journalism, not fighting over how names are understood outside the community.
$300MM has been set aside for DOE QIS alone (with more of a focus on simulation), and that is likely to ramp up with papers like this, probably somewhere over $1B over the next 5 years for DOE Science alone. Throw in DOD/NSA and the number is easily going to be in the $5-10B total over the next 5-10 years, assuming there's no quantum winter.
>QUANTUM INTERFERENCE IS JUST WHAT QUANTUM PROCESSORS DO, ITS A BUG, NOT A FEATURE
This sort of throws the whole series of tweets into question for me. Of course interference is a feature - you want to create a pattern of interference where paths leading to the wrong answer interfere with each other and cancel out! Without interference I don't understand how quantum computers could even work, what they would look like, and why we would want to use them for anything.
>which, to me, is an infuriating thing to label “quantum supremacy” because quantum interference is EXACTLY WHY WE CAN’T USE CURRENT QUANTUM PROCESSORS TO “BREAK ALL CRYPTO” IN THE FIRST PLACE BECAUSE WE CANNOT DO EFFICIENT QUANTUM ERROR CORRECTING CODES
Error correction requires more qubits to do the error correction. We need the current qubits just to do the calculations, leaving us no qubits to use for error correction. Quantum interference certainly isn't the reason we can't do error correction.
If the author is confusing decoherence and interference, then I can understand why they believe what they do, though that confusion ultimately removes a significant portion of their point. Decoherence is what takes something in superposition and puts it back into the realm of classical physics - we lose the ability to utilize that quantum interference and entangled qubits. Ultimately to get a result we have to de-cohere the qubit, because we have to observe it, so not all decoherence is bad. The problem is all sorts of things besides our desired observation can cause decoherence, which results in errors, and avoiding this requires implementing error correction, which takes additional physical qubits. We need a lot more physical qubits, qubits that are more resistant to decohering when we don't want them to, and/or for someone to come through with a breakthrough that does error correcting much more efficiently than the methods Shor came up with.
Of course, I might be the one that's confused here.
And the test they did show that they actually achieved interference. How you'd call that quantum supremacy is a bit of a strech tough if you ask me. Looks to be like saying 'hey, a quantum system can simulate quantum behavior quicker than a classical computer' which is kinda implied
Quantum supremacy cannot be claimed until this possibility is ruled out.
As a quantum computing researcher, I can't make head and tail of what OP is saying after and including tweet 7. I don't think OP understands interference correctly. As someone points out elsewhere in the comment section, she might mean decoherence, but I can only evaluate what she has written.
She also makes light of the theoretical computational complexity results underlying the demonstration of quantum supremacy using random circuits. This experiment's results and interpretation might be iffy at best, but the underlying strategy of the quantum computing community in this matter are sound. We don't want to keep asking for funding for the next 20 years without proofs of principles in between, and this experiment is one step along the way.
Let the computation power grow exponentially, Until one day, computation faces its vulnerability.
Let all be known, beautiful dawn holds its crown.
Computation is a growing pyramid, da da da, dancing on a brittle tip.