Announcing the D-Wave 2X Quantum Computer

[w0000t]

http://www.dwavesys.com/press-releases/d-wave-systems-breaks...

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.

[ericmarcos]

The D-Wave computer is called a quantum computer because it uses some quantum properties when running a simulated annealing kind of algorithm (which is a well known classical algorithm so find sub-obtimal solutions to combinatorial problems, aka NP-Complete problems). But it is NOT a universal quantum computer in which one could run Shor's or Groover algorithms. In order to do that, you need to keep a quantum system with entangled qubits, something that is extremely difficult to achieve due to quantum decoherence, etc.

So, saying that "the new processor considers 2^1000 possibilities simultaneously" is basically a ton of bullsh. Even a real quantum computer cannot do that effectively.

Nevertheless, I think D-Wave is doing a great work and is definitely taking steps towards a real QC.

[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.

[murbard2]

The statement is also a common fallacy that Scott Aaronson has addressed many times. While some exponential speedups are possible, there are no indications that they are possible in general for problems in NP, and even if they were, we know that they would have to use the structure of the problem and not merrely "consider possibilities simulatenously"

[eggie]

I also would love to hear someone who works in the space explain this.

[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?

[BrainInAJar]

The results are not just a bit misleading, they're incredibly misleading and a downright lie. See eg: http://www.scottaaronson.com/blog/?p=1400

""CPLEX is a general-purpose, off-the-shelf exact optimization package. Of course an exact solver can’t compete against quantum annealing—or for that matter, against classical annealing or other classical heuristics! """

DWave is snake oil in the worst possible way.

[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.

[tachyonbeam]

AFAIK this kind of problem is easily parallelized, and it should be possible to accelerate it using GPGPU... So, they may not be able to beat a well-tuned implementation on a desktop workstation with a few GPUs costing less than 10K.

[Beltiras]

I think the most significant gain made here is not speed but power consumption. 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". 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

[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?

[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 - 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...

[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!

[dan-bell]

A friend of mine has been leaning the basics with this: http://qcplayground.withgoogle.com/#/home

[pakled_engineer]

Common Lisp http://www.dwavesys.com/careers/senior-software-developer

[LASR]

There is one button - "on". There is no program. The program is baked into the machine itself. The input data is carefully prepared and fed into the system. The machine then runs and spits out the output. That's it.

You should think of it more as a piece of lab equipment rather than a computer.

[hodwik]

>What language is used to program for this processor?

Dwave doesn't work that way. You can think of it like an ASIC that can only do a single clock cycle as you bring it into a quantum state.

The only way to prepare for this stuff is by learning the proposed quantum algorithm maths.

[meatysnapper]

Think of a quantum computer as an analog computer. You don't program it, you construct it.

[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.

[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

[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.

[eternalban]

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