
Turn down the quantum volume - furcyd
https://www.scottaaronson.com/blog/?p=4649
======
ggm
I think the function should be something like "number of stable QBits which
can demonstrably add to an implementation of Shors algorithm"

So it excludes DWave, and the unstable QBits, and focusses on a specific known
problem which (I believe) gets closer to e.g. breaking useful real-world
unknown value RSA, rather than simply being "how big it is"

As long as a graphics card is just painting pixels its mainly about
entertainment. When somebody says "this graphics card can now exhaustively
search 20 letter password strings against a known hash string and find your
passphrase in under 30 seconds" then its a real issue.

~~~
core-questions
Why does any reasonable function need to exclude D-Wave by default? Aren't
they the only company with an actual, publicly-accessible, realtime production
system you can use?

I know it's not gate model, but it does compute using quantum effects, and so
any reasonable model of performance has to include for this sort of system.

IIRC D-Wave doesn't like single digit performance indicators, so they're
aligned with Aaronson on this for once.

~~~
fsh
There is no indication (not even from the theory side) that the D-Wave
approach can achieve any speed-up over a classical computer. This is one of
the reasons why Aaronson and many others in the field are not taking them
seriously. Sure, they will gladly sell you a system, but the whole
architecture will most likely never be useful for anything.

~~~
correlaterdude
> There is no indication (not even from the theory side) that the D-Wave
> approach can achieve any speed-up over a classical computer.

You're wrong about the theory side of things[1, 2], by the way. The discussion
around adiabatic quantum computing is weirdly politicized. It's true that
D-Wave's computer isn't a universal quantum annealer; but _in theory_ such a
thing is equivalent to a gate-model computer.

[1]
[https://arxiv.org/pdf/1611.04471.pdf](https://arxiv.org/pdf/1611.04471.pdf)

[2]
[https://iopscience.iop.org/article/10.1088/0256-307X/35/11/1...](https://iopscience.iop.org/article/10.1088/0256-307X/35/11/110303)

~~~
krastanov
An adiabatic quantum computer is equivalent to the gate model. D-Wave do not
have an adiabatic quantum computer, so there is indeed no reason, even
theoretical, to believe their hardware provides computational advantage. The
word "quantum annealer" is just a confusing term used differently by everyone,
occasionally meaning "adiabatic quantum computer" and occasionally meaning
what D-Wave have.

------
nrclark
Not trolling, but curious - do quantum computers do anything useful yet?

~~~
dekhn
No. There have been some interesting quantum simulation papers but nobody has
shown anything yet that is revolutionary.

This is promising work that may be interesting in the future:
[https://arxiv.org/pdf/1902.10171.pdf](https://arxiv.org/pdf/1902.10171.pdf)

This also looks like it could be interesting:
[http://meetings.aps.org/Meeting/MAR20/Session/W17.7](http://meetings.aps.org/Meeting/MAR20/Session/W17.7)
(Gurobi is a CPU solver for integer and linear programming problems, which are
some of the most useful to solve quickly.

There is also: [https://ai.googleblog.com/2016/07/towards-exact-quantum-
desc...](https://ai.googleblog.com/2016/07/towards-exact-quantum-description-
of.html)

~~~
kaiabwpdjqn
can you give an example of a linear programming task that is not currently
practical to solve on classical computers but could become so with a huge
speed up?

~~~
alex_anglin
Simulated annealing[1] versus Quantum annealing[2], though it’s not there yet
practically speaking as I understand it.

[1]
[https://en.wikipedia.org/wiki/Simulated_annealing](https://en.wikipedia.org/wiki/Simulated_annealing)

[2]
[https://en.wikipedia.org/wiki/Quantum_annealing?wprov=sfti1](https://en.wikipedia.org/wiki/Quantum_annealing?wprov=sfti1)

~~~
kragen
Simulated annealing is not a linear programming problem!

------
darawk
Why isn't it defined in terms of the solvable problems? This quantum computer
can factor an n-bit composite number seems like a fairly objective test.

~~~
fsh
It's a marketing problem. Shor's algorithm seems to be extremely hard to run
without cheating by "optimizing" the program on a classical computer that
already knows the answer. Nobody wants to announce that they barely managed to
factor 21 or something like that, while at the same time trying to convince
the public that their system is somehow superior to classical computers.

------
shireboy
What he advocates makes sense. Marketing for classical computers used to make
hay about how fast the CPU was in Khz, Mhz, Ghz. This is done less now since
people recognize that is just one of several factors when comparing devices.
It's still mentioned, just alongside the architecture, ram, GPU, etc. It can
be hard to compare if you're not up on all the differences.

~~~
vortico
People now buy CPUs and GPUs based on primarily one index: how many fps their
favorite games can run at their desired resolution and quality. So
manufacturers of QCs should do the same by specifying what problems at what
sizes their hardware is best at solving.

------
amelius
Or in other words: fire your marketing department.

