"...we have begun computing across parallel universes if one believes that particular interpretation of quantum strangeness."

Well, I do and I don't, if you know what I mean.

Here's a question for any passing scientists: could quantum computers be used to test the multiple worlds interpretation of quantum physics, i.e. are there any particular behaviours they might exhibit that would be evidence that it is/isn't true?

When it comes to the usefulness of these things, are they just faster? Or is there more to it than that? If so, what?

One view that has been quite prevalent in recent years is that quantum computing effectively means the end of traditional crypto (Simon Singh, if memory serves, plus many others).

Given that the one time somebody attempted to explain the operation of a quantum logic gate to me, I ended up feeling even more ignorant than I had been prior to the explanation, I'm certainly not qualified to judge whether this is that type of quantum computing.

But if it is, the implications are profound, to say the least.

From what I can make out it seems to be a super-cooled super computer that is so powerful that it has the computing capability to run very sophisticated programmes even to the extent to programme itself.
But I would think that is more in the software
It does not seem to be anything that really ventures into the world of quantum physics.

This exchange seems a little unnecessarily obscure, and the final question/answer strange:

HPCwire: What is "quantum annealing?"

Rose: Quantum annealing is a prescription for solving certain types of hard computing problems. In order to run quantum annealing algorithms, hardware that behaves quantum mechanically -- such as the Rainier processor in the D-Wave One -- is required. Quantum annealing is conceptually similar to simulated annealing and genetic algorithms, but is much more powerful.

HPCwire: Can you prove that quantum computing is actually taking place?

Rose: This was the question we set out to prove with the research published in the recent edition of Nature. The answer was a conclusive “yes.”

It almost sounds as though they found it wandering around in a swamp, somewhere, rather than built it themselves.

Doesn't mean the end of crypto, only the end of certain types of algolrithms. It may well kill PGP/GPG and other factoring based methods since factoring algorithms are of great interest in the quantum computer world.

It does make RSA style crpto obsolete. But (to ref Simon Singh again) There is the possibility of quantum cryptography (not directly related to quantum computing) but and this is a huge "but" Quantum Cryptography relies essentially on the physical medium of info exchange in a way traditional communications don't. Quantum Cryptography is also in principle unbreakable unless...

Unless physics can shift beyond QM into... God knows where which I think neatly answers Andrew's very interesting question.

I just had a holy crap moment. Quantum computing applied to simulated annealing and genetic algorithms. That almost runs chills done my spine.

According to the comments thread at this Google Research article on their work with D-Wave, there is indeed some doubt as to whether it's really a quantum computer or not. But it's pretty much over my head.

The thing that worries me most about quantum computing isn't the implication for crypto, it's that I don't even begin to understand it. Ones and zeroes doing boolean logic I can handle, even if I'm not as good at it as I'd like; rf-squid flux qubits realizing adiabatic quantum algorithms, er... crumbs.

I've been waiting for this device to be revealed as a fraud since I first read about it. The current record for the number of qubits coherently entangled under laboratory conditions long enough for a calculation to be performed is 16 (sixteen). It is inconceivable that there is a commercial 128 bit device.

The reason why it is so unlikely is this, every extra qubit you add to the set of entangled qubits doubles the computational power, that's why quantum computers are so attractive. Unfortunately, every extra qubit is twice as hard to add to the set as the previous one.

It's a bit like juggling, the fourth ball is harder to add than the third, the fifth harder than the fourth, and so on.

I have followed quantum computing for a decade and I believe a useful quantum computer to be pure science fiction.

However... Lockheed Martin is not exactly a house of cluelessness. They have some of the sharpest engineers around in Defense technology. Given a choice between believing what some random person states in a comment versus what LockMart says by paying hard money (a lot of it), guess who I am going to believe...

I worked at a facility that had a Cray 2 supercomputer, which was rather new at the time. We used VAXes and similar iron to load this thing up for a set of calculations, of the type that, say, an Air Force customer might be keenly interested in. While the Cray was very good at what it did well, it did almost everything else abysmally, which meant that the real domain of problems we could solve with the bubbling hardware were so constricted as to make it an almost single-purpose machine. It wasnt even that great of a conversation piece, as it would shut down if you took a flash picture of it.

Lets say LockMart has many qubits all entangled and calculating nicely... it will be some time before actual useful work could be done with those.

The number of entangled qubits has, over the last decade, gone up by about one every couple of years. Perhaps LM built a time machine and fetched it back from 2250 ;)

Seriously Dale, this is the state of the art. What LM have is some kind of quantum computer simulator. Useful for some applications, no doubt, but not a quantum computer.

I don't really understand these new computers, I just hope they put the internet even further beyond governments and their desire to regulate.

Is it possible that there's two things going on here?

1. The engineers at Lockmart have specified and purchased a new supercomputer, unique in some was (as such things tend to be) and, while it may not be a quantum computer in the classical "all your prime are belong to us" sense, it is what they asked for, so they are happy and have not been deceived.

2. Distinct from this, the manufacturers of said super computer have chosen to market it as a "Quantum Computer", on the basis of certain aspects of whatever makes it unique (possibly the simulation that Roue le Jour suggests, I really wouldn't know).

the other rob, you are entirely correct, I was being too bombastic, as sometimes happens when you feel strongly about something.

The D-Wave machine is not a true quantum computer. It has some similarities but it does not function in the same way and cannot perform all the functions of a quantum computer, for example the Shor algorithm which potentially factors large primes and is responsible for the 'oh noes, all my emailz is belong to evil government' nonsense. Its manufacturers freely admit this, but claim it is sufficiently similar to do useful work on a certain restricted set of problems. No doubt LM have purchased one to see if that is true.

A quantum computer would be a wonderful thing to have, yet the best efforts of very bright guys working for years has only yielded a few laboratory novelties that are easily out performed by any PC. I don't believe a useful device, a thousand qubits say, will ever be built. In spite of this, D-Wave insist on describing their product as a quantum computer. It annoys me in the same way that describing perfectly ordinary private key encryption with secure quantum key distribution as 'quantum encryption' does. It smells too much of snake oil.

So now your personal data will not only be stolen by some hacker in Indonesia, it will also be read by the Borg.

Having thought about this overnight, I can see there is a better analogy. It is perfectly possible for an information processing machine to do useful work without meeting the criteria for being a computer, the simple calculator springs to mind. The D-Wave machine is not a quantum computer. It is a quantum calculator.

I want to go to the universe where a certain terrorist missed in 1914 - even if the war is delayed (rather than prevented) the world is still utterly different and (I believe) much better.

Regardless of general opinion, this is still a major feat, even if it isn't a full Quantum Computer. I think that the real thing that gives it away is that it is programmed in a standard and existing language.

The reason while we have all but abandoned neural nets is that they can't be conventionally programmed; they must be trained and the resultant is non-deterministic.

I real Quantum Computer would require completely new concepts in programming which in turn requires a completely new language. However, that is most certainly a chicken-and-egg issue, non?