What You Shouldn't Know About Quantum Computers
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Re: What You Shouldn't Know About Quantum Computers
#2At first I thought that the introduction was hyperbole, but the write-up does actually more or less deliver on it. Written in plain English that anyone can grok, it's a good summary of what quantum is, what it isn't, and why you should care. Definitely recommend reading if, like me, you're not too familiar with the field.
Re: What You Shouldn't Know About Quantum Computers
#3The article suffers from skipping between layers of abstraction in an attempt to make a point, and in the end in doing so fails to make the initial point.
In the first "Myth" section, that "nobody understands this quantum stuff", the example is used of the transistor. It's true that we have no way of making a classical model of a transistor, and our understanding of how transistors work relies on quantum mechanics.
But we did not invent transistors from quantum physics -- we created transistors long before we had an explanation of how they worked, and we have continued to improve and iterate by making advances in material sciences and experimentation, not by applying first principles. Things like blue LEDs were invented by tinkering rather than by solving Lagrangians.
The final section was of particular interest to me; Gil Kalai's work on quantum error correction is very interesting to me and I am in the camp that believes that quantum computing is not possible in any useful sense; in particular a quantum computer will not be capable of being significantly more powerful than a classical computer, in the quantum supremacy sense.
Here the author reverts to a simplistic argument that "of course" quantum computers are possible, because we can model a quantum computer in a traditional computer. But this sidesteps the main claims, which are whether it is possible to scale error correction to the point where a useful result can be achieved.
Even in the domain of NISQ, which is roughly the equivalent of running fluid dynamics simulation in a bathtub, we have yet to produce results showing that we can scale significantly better than a quantum computer.
Re: What You Shouldn't Know About Quantum Computers
#4The article suffers from skipping between layers of abstraction in an attempt to make a point, and in the end in doing so fails to make the initial point. In the first "Myth" section, that "nobody understands this quantum stuff", the example is used of the transistor. It's true that we have no way of making a classical model of a transistor, and our understanding of how transistors work relies on quantum mechanics. B…
> The final section was of particular interest to me; Gil Kalai's work on quantum error correction is very interesting to me and I am in the camp that believes that quantum computing is not possible in any useful sense; in particular a quantum computer will not be capable of being significantly more powerful than a classical computer, in the quantum supremacy sense.
My question too. I've had a vague feeling about this for a long time, waving my hands about thermodynamics with "It must get exponentially harder per qbit to eliminate thermal noise by cooling down closer to absolute zero," and I'd really like to get past my hand-waving and see what the dynamics really are.
Re: What You Shouldn't Know About Quantum Computers
#5Chris Ferrie also writes great books about science for babies.
https://www.csferrie.com/books
https://www.amazon.com/Quantum-Computing-Babies-Baby-Univers...
Re: What You Shouldn't Know About Quantum Computers
#6The linked paper touches on quantum error correction but doesn't explain what the state of the art is. Has any team successfully demonstrated a single usable logical error-corrected qubit yet? I saw this article two months ago https://physicsworld.com/a/why-error-correction-is-quantum-c... discussing the topic, but the writing makes it unclear exactly what was achieved by the various groups. Is recovery from a finite number of errors sufficient to make a usable logical cubit, or is more work still left to be done?
Re: What You Shouldn't Know About Quantum Computers
#7> Researchers like Jaime Sevilla and Jess Riedel support this timeline, publishing a report in late 2020 that claimed a 90% confidence of RSA-2048 being factored before 2060.
I am skeptical. 36 years is a long time, but in the past 10 years there hasn't been much progress:
year 2001: factorization of 15 (IBM)
year 2012: factorization of 21 (University of Bristol)
year 2019: factorization of 35 attempt, failed (IBM)
Re: What You Shouldn't Know About Quantum Computers
#8The article suffers from skipping between layers of abstraction in an attempt to make a point, and in the end in doing so fails to make the initial point. In the first "Myth" section, that "nobody understands this quantum stuff", the example is used of the transistor. It's true that we have no way of making a classical model of a transistor, and our understanding of how transistors work relies on quantum mechanics. B…
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Re: What You Shouldn't Know About Quantum Computers
#9> Researchers like Jaime Sevilla and Jess Riedel support this timeline, publishing a report in late 2020 that claimed a 90% confidence of RSA-2048 being factored before 2060. I am skeptical. 36 years is a long time, but in the past 10 years there hasn't been much progress: year 2001: factorization of 15 (IBM) year 2012: factorization of 21 (University of Bristol) year 2019: factorization of 35 attempt, failed (IBM) h…
IIRC none of those uses of shor's algorithm were real (well maybe the 2019 one was, but that failed).
There's a threshold you need to reach for quantum error correction to work and we are approaching it pretty steadily on a log scale.
Re: What You Shouldn't Know About Quantum Computers
#10The linked paper touches on quantum error correction but doesn't explain what the state of the art is. Has any team successfully demonstrated a single usable logical error-corrected qubit yet? I saw this article two months ago https://physicsworld.com/a/why-error-correction-is-quantum-c... discussing the topic, but the writing makes it unclear exactly what was achieved by the various groups. Is recovery from a finite…
I think this is the SOTA
https://s7d9.scene7.com/is/content/quantum/LQ_ErrorCorrectio...
the corrections significantly decrease the error rate but they need to do a lot of preselection, so it isn't quite useful yet.