
Announcing the D-Wave 2X Quantum Computer - johlo
http://www.dwavesys.com/blog/2015/08/announcing-d-wave-2x-quantum-computer
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w0000t
[http://www.dwavesys.com/press-releases/d-wave-systems-
breaks...](http://www.dwavesys.com/press-releases/d-wave-systems-
breaks-1000-qubit-quantum-computing-barrier)

This announcement, claims:

 _Every additional qubit doubles the search space of the processor. At 1000
qubits, the new processor considers 2^1000 possibilities simultaneously, a
search space which dwarfs the 2^512 possibilities available to the 512-qubit
D-Wave Two._

Since we still aren't able to factor any large numbers with it, those 2^1000
bits don't really work like they say they do. I'm guessing there are many
caveats behind their description.

I would appreciate any explanation from an expert.

~~~
daivd
It is not a conventional quantum computer. You cannot use it to factor
numbers. You use it to find approximate solutions to optimization problems.

~~~
thomasrossi
Well, I will tell one relevant problem that can be annihilated with this: ads
placement. Google advertisement adwords is all based on a auction mechanism at
the end of which you have to find the best allocation of ads to bidders (to
slots) - which has an evident combinatorial nature, to find optimum you should
try all possibile combinations. This is typically solved in approximated ways.
It may not be a "conventional quantum computer" but it's pretty usefull
anyway:) I can't wait to toy with one..

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mechagodzilla
These results seem a bit misleading - they're comparing their multi-million
dollar system to a classical optimizer running single-threaded on a 3-year old
processor (Intel Xeon E5-2670), and then saying 'look how much faster we are
than a classical optimizer!'

How does this compare to a giant cluster of new Xeons with faster
interconnects?

~~~
nwah1
Not to mention the continual energy requirements of cooling a system to near
absolute zero, in addition to the fixed cost of the system. Although there are
almost certainly some specialized niches where it would make sense.

~~~
agsamek
> Although there are almost certainly some specialized niches where it would
> make sense

I don't think so. I haven't heard of any and would like to learn about even
one that was validated by any of: algorithms experts or real life.

~~~
nwah1
My understanding is that quantum computers are very good at simulating quantum
physics. Which, granted, probably doesn't have many commercial applications.

~~~
gjm11
"Normal" quantum computers are good at simulating quantum physics, or would be
if we could build big enough ones. D-Wave's adiabatic allegedly-quantum
computer is not, so far as anyone knows.

The only thing (so far as I am aware) that anyone knows how to do with
D-Wave's machine is to use it to find approximate solutions to certain
optimization problems. The last I heard, it did so slower than a standard-
issue laptop running (non-quantum!) software designed to find approximate
solutions to the same optimization problem that D-Wave's underlying hardware
models.

That was before the release of the latest D-Wave machine. I don't think it was
ever clear whether D-Wave's device scales better than a conventional computer
when trying to solve larger problems. Perhaps it does, in which case their new
$10M machine may outperform commodity laptops.

[EDITED to add: see [http://www.archduke.org/stuff/d-wave-comment-on-
comparison-w...](http://www.archduke.org/stuff/d-wave-comment-on-comparison-
with-classical-computers/) and the other pages linked therefrom for some
comparisons between D-Wave's reported performance and that of some heuristic
optimization software running on a commodity laptop. Disclosure: the author is
a friend of mine.]

------
Beltiras
I think the most significant gain made here is not speed but power
consumption. On [http://www.dwavesys.com/d-wave-two-
system](http://www.dwavesys.com/d-wave-two-system) they compare a
supercomputer using almost 2 gW while 2X uses 27 kW when you factor in "the
fridge". I don't know if that's an apples-2-apples comparison, hoping the
supercomputer is set up to solve comparable problems. If I am understanding
this properly they have a great product on their hands and a great deal of
units to make.

~~~
sbierwagen

      On http://www.dwavesys.com/d-wave-two-system they compare a 
      supercomputer using almost 2 gW while 2X uses 27 kW when 
      you factor in "the fridge".
    

Megawatts, not gigawatts. A gigawatt is a thousand times larger than a
megawatt, and a million times larger than a kilowatt. A two gigawatt computer
would consume the entire output of a large coal power station, such as
[https://en.wikipedia.org/wiki/Homer_City_Generating_Station](https://en.wikipedia.org/wiki/Homer_City_Generating_Station)

~~~
Beltiras
Ouch, mybad there, brainfart (and can't edit anymore :( )

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arvinjoar
Cue blog post by Scott Aaronson, will be interesting to hear his take on this.

~~~
acqq
Just read older discussions, up to now they didn't even prove that they are
faster than "conventional" computing. Is this now going to be faster?

~~~
wsha
According to Aaronson and others, the D-Wave architecture has not demonstrated
any behavior that can't be explained using classical physics, so just making
the device bigger shouldn't change it into a quantum device with a quantum
speed up. That said -- who knows, maybe the architecture is different enough
from everything else that it could be a better classical annealer than
standard processors (though it's only ~1000 bits, so it probably can't
outperform any conventional processor sold today with billions of bits).

~~~
Strilanc
> _According to Aaronson and others, the D-Wave architecture has not
> demonstrated any behavior that can 't be explained using classical physics_

That's not Scott's definitive opinion anymore. For example, from [1]:

> _Now, I’d say, D-Wave finally has cleared the evidence-for-entanglement
> bar—and, while they’re not the first to do so with superconducting qubits,
> they’re certainly the first to do so with so many superconducting qubits.
> [caveats about D-wave over-hyping and not having a demonstrated speedup
> yet]_

1:
[http://www.scottaaronson.com/blog/?p=1400](http://www.scottaaronson.com/blog/?p=1400)

~~~
acqq
Yes, but _no demonstrated speedup_ problem still remains.

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logicallee
Didn't we just read about the NSA moving to quantum resistant algorithms a few
days ago?

[https://news.ycombinator.com/item?id=10064226](https://news.ycombinator.com/item?id=10064226)
\- NSA announces plans for transitioning to quantum resistant algorithms

also I found this from a few hours ago:
[http://arstechnica.com/security/2015/08/nsa-preps-quantum-
re...](http://arstechnica.com/security/2015/08/nsa-preps-quantum-resistant-
algorithms-to-head-off-crypto-apocolypse/)

------
taylodl
What language is used to program for this processor? I wouldn't think you'd
take the same approach programming a quantum computer as you would a
conventional computer. Is there a quantum computer simulator? What does the
development workflow look like? How do you debug? Boy I have a lot of
questions!

~~~
pakled_engineer
Common Lisp [http://www.dwavesys.com/careers/senior-software-
developer](http://www.dwavesys.com/careers/senior-software-developer)

~~~
hodwik
That's not to program for D-wave. They just need software developers in-house
for their tooling.

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sshb
It would be nice to have these computers available in public clouds. It is not
trivial though.

~~~
minthd
At least, getting access to some pretty programmed algorithm running on a it
on a cloud should be easy enough to do.

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khed
There was a paper in 2008 claiming that adiabatic quantum computers could
factor with a quantum speed up.
[http://arxiv.org/abs/0808.1935](http://arxiv.org/abs/0808.1935)

~~~
krastanov
Adiabatic quantum computers are polynomially equivalent to what is usually
referred as quantum computer so no surprise there. Dwave is neither, nor is it
faster than classical computers. At best it is somewhat interesting from an
engineering point of view.

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eternalban
Wake me up when we have quantuum networking gear and magical perfect locality
:)

