
Quantum Computing Is Real, and D-Wave Just Open-Sourced It - jonbaer
https://www.wired.com/2017/01/d-wave-turns-open-source-democratize-quantum-computing/
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ramshanker
TL:DR They open sourced a software library for encouraging "Not familiar with
quantum physics" programmes to get started.

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ThePhysicist
If it is real now, why can't we do the following:

1\. Take a problem that is impossible to solve with classical computers (e.g.
from combinatorics, number factorization), but whose solution can be verified
easily.

2\. Solve it on their quantum computer.

D-Wave keeps saying they have a quantum computer since 5 years now, yet they
have not produced any proof of quantum speed up achieved with their machine.

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wolfgke
For a long time it was controversial whether D-Wave's systems even used
quantum effects - but now the consensus is that they do. D-Wave's systems
implement some (restricted) kind of adiabatic quantum computing/quantum
annealing. Even from a theoretical perspective it is up to now hardly
understood in what sense quantum annealing is more powerful (in terms of
better possible running time opposed to classical annealing combined with
specialized algorithms). So you cannot simply implement some well-known
quantum algorithm as Shor's on D-Wave's systems.

~~~
ThePhysicist
Yes I understand that quantum annealing is different, but the whole point of
having a quantum computer is that it is able to solve interesting mathematical
problems, or at the very least is able to simulate other quantum systems
efficiently (beyond nearest-neighbor Ising models). To my understanding, the
D-Wave system has demonstrated neither of these things so far.

~~~
wolfgke
> but the whole point of having a quantum computer is that it is able to solve
> interesting mathematical problems

> To my understanding, the D-Wave system has demonstrated neither of these
> things so far.

There are different opinions whether D-Wave's quantum computer is able to
solve _interesting_ mathematical problems. Here are some - decide for yourself
whether you consider them as interesting or not (I'm personally on the side
that it is not the kind of application _I_ am interested in, but can imagine
that there might be people for whose these might be useful):

> [https://www.quora.com/What-are-some-cool-possible-
> applicatio...](https://www.quora.com/What-are-some-cool-possible-
> applications-of-the-D-Wave-quantum-computer)

Here D-Wave's marketing about applications - read them with a grain of salt
;-) :

> [http://www.dwavesys.com/quantum-
> computing/applications](http://www.dwavesys.com/quantum-
> computing/applications)

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sauronlord
They still can't get their gate fidelity anywhere close. Nice PR move ...again

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Bombthecat
Heh, I would be really surprised if it would work "now".

Maybe in five or ten years though

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sigmaprimus
I'm wondering why people think that the argument that because the Dwave system
can only solve 1 problem or in fact only 1 subset of a problem disqualifies it
from being a quantum computer is valid. Last time I checked a conventional
computer only solves 1 problem at its core. Are quantum computers measured
with a different stick?

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ThePhysicist
But what problem can it actually solve?

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sigmaprimus
Well there is the salesman example in the article for one, I find the checker
board problem much easier to wrap my head around. On a checker board you have
64 squares, half are red and half are black, everywhere a red touches a black
square is a junction point. How many junction points are there? Now that you
know how many junctions there are how many different ways can you lay out
those red and black squares to make that same amount of junctions? What if 3/4
of the squares were black? My understanding is that the Dwave system will
produce a number of answers that are close to correct, and a majority that are
correct (probably). Things start getting really tricky when you make the
squares into cubes and run the problem again, or if you want to get really
bent add a fourth dimension to the problem.

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ThePhysicist
Yes but even for the traveling salesman problem (which in most variants is NP-
complete) there is -to my knowledge- no experimental or even theoretical proof
that an adiabatic quantum computer could outperform a classical one.

The fact that the D-Wave computer is a computationally complex quantum system
does not automatically imply that the dynamics of the system can be harnessed
to solve computationally complex problems, because we usually don't have
sufficient control over the system. Given the ability to control individual
degrees of freedom of a given system with arbitrary precision almost anything
can be turned into an exponentially powerful classical or quantum computer,
even a simple hot cup of tea. The problem is that we often don't have the
means to exert the required control over the system, and this is the core
problem with all current approaches to quantum computing, adiabatic or not.

So, yes, you can encode the solution to many problems in the ground state of
the Hamiltonian of a coupled qubit system, but reliably keeping the system in
this ground state while transforming it into the target state turned out to be
impossible in any real-world system so far, as even the tiniest thermal
fluctuations will trigger state transitions during the annealing process and
ruin the whole thing.

So if D-Wave really claims they have a working quantum annealer on their hands
I want to see proof, and if they can muster it I'm pretty sure they'll get a
nobel prize in return. Show me the data!

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sigmaprimus
Wow, blind me with brilliance or baffle me with bs, you are obviously much
smarter than me and I conside to you. All that I ask is that you use your
knowledge to help what I feel is a pioneering company with an idea that even
the smartest minds...including yours have had to concede that these guys have
something. They have pulled up their skirt and offered you an opportunity to
make something great and you want to bicker over their har color.

~~~
sigmaprimus
I must apologize for that last comment as I phrased it in a demeaning
context..the truth is we (humanity) need your help and rather than fight over
Synaptics I emplore you to focus your valuable experience and knowledge to
pursue this area of computer science in the direction of achieving the greater
good rather than a geekisH slap fight that gets us nowhere. You seem like a
smart guy, fix the issue by creating something great and make america great
again.

~~~
ThePhysicist
No worries, my critique is not aimed at you but at the way D-Wave is doing PR,
as I think it does serious damage to all other companies in this field and
will hinder progress in quantum computing. I understand that you need to do
some marketing as a tech company, but there is a difference between being
optimistic and visionary about what you want to do, and simply telling people
that you already did it without handing over any proof. After what happened
with Theranos I really wish tech journalists would be more careful when
reporting about supposedly revolutionary technologies like these, especially
if there is no independent evidence available to back any of the claims made.

