Web Quantum Computer Simulator

Heraklit writes "As reported on Heise News, the Frauenhofer Institute of Computer Architecture and Software Technology has made available the first online quantum computer simulator - it will be simulating up to 31 quantum bits, for testing new advanced quantum algorithms. Behind the scenes, it is a 32 node Athlon 3200 Myrinet Linux Cluster with 56GByte RAM! Now imagine the computing power of a few hundred qubits, if ever constructed..."

maybe they should read /. more?

[garcia]

Wow, I really hope that they didn't put those 32 processors and 56GB of DDR RAM into use for this [fraunhofer.de]. Sounds like they should have read this [slashdot.org] article instead. Maybe it would have been cooler and not so grainy!

For the quantumly challenged amoung us

[Timesprout]

ie me, can somebody please explain in lay persons terms what simulation of quantum processes involves?

On the Horizon

[WarriorPoet42]

The techs that can come for this computing power is unimaginable. Several physicits have said that it would take a quantum computer on the scall of a contemporary computer to achieve feats such as teleportation (Star Trek, eat your heart out!)
Michael Chricton (of course) has dealt with the subject quite entertainingly in the novel Timeline. Again, I say the novel.

...simulated?

[Cyclotron_Boy]

The scaling is not 1:1, so while it takes 32 Athlon processors with 56GB of ram, the processing power of 31 qbits is not that of the 32-processor cluster. This is an emulator, so the actual 31-qbit probably isn't quite as powerful as the hardware required to accurately mathematically model it. So while the computing power of a few hundred real qbits might be impressive, the computing power required to simulate those few hundred qbits would be extremely impressive.
-F

a real QC would be 2^31 times faster

[menscher]

I know everyone's excited about this, but keep in mind that it's 2^31 times slower than the thing it's trying to simulate. That's because it can't really take advantage of the exponential speedup from working with entangled states. Or, more accurately, it gets an exponential speedup at the cost of an exponential slowdown.

The problem with quantum computing . . .

[muskr]

For those of you who don't know: The biggest problem with quantum computing is that you can never extract all the information you compute. So you can process y=f(x) for 2^31 values of x simultaneously, but when you go to read y from the computer, you just get one solution, and what's worse, you don't even know which value of X it corresponds to!

Using Shor's factoring algorythm, however, you can extract one of the factors of a large number without knowing all the other factors. That would be useful for public key encryption. I wouldn't worry about your PGP key just yet though. 7 q-bit computers [ibm.com] are incredibly difficult to make. The process used to make the 7-bit QC does not scale to larger numbers easily. 2048 bit computers are way beyond our technical skills.

On a side-note, I wonder if each computer simulates a q-bit (with one responsible for management). It would be the most obvious way to run the simulation, but may or may not be the fastest. There would need to be a lot of cross-communication since all the q-bits are entangled in any interesting quantum computation.

Re:On the Horizon

[Jerf]

Several physicits have said that it would take a quantum computer on the scall of a contemporary computer to achieve feats such as teleportation (Star Trek, eat your heart out!)

References please? The fundamental problem with teleportation is the impossibility of simultaneouly (or even a reasonable appoximation thereof) introducing kilograms of matter to kilograms of other specially entangled matter, and sending the still-necessary "decoding" data stream to the reciever.

By my count that's at least three impossible things. In order from least impossible to most:

1. Sending the data stream anywhere in any reasonable amount of time. (It's that last clause that's a real killer, but this might be possible to some degree.)
2. Introducing the teleportee to the entangled matter... imagine trying to touch every atom in your body simultaneously. You can't just smoosh the teleportee into the matter, it won't work. Oh, and no fair killing the teleportee to do it.
3. Creating kilograms of entangled matter in the first place, and managing to keep it from reacting to its environment so it stays entangled... for entire seconds, days, weeks, years. Uh-uh, nope, not in this universe.

I don't see how QC helps with any of these.

(It's funny how something like this brings out all the physics fanboys who, in their ignorance of physics bounded only by Star Trek, honestly think we're making some sort of progress towards teleportation and the other impossibilities. Instead, real physics just keeps stacking up the reasons why these things are impossible, and the possibilities are receding, not advancing. Why do I have the sneaking suspicion WarriorPoet42's "several physicists" are just "some other teenager I found on a web board somewhere who likes to dazzle other fanboys with his command of physics^W Star Trek buzz-words"?)

Re:Life, The Universe, & Everything

[Zak3056]

And this quantum computer simulator contained the whole answer to Life, The Universe, and Everything...

Until somebody went and looked at it.

You're modded "Funny" but I actually found the post interesting. And here's why:

There's a bit on THHGTTG that goes

There is a theory which states that if ever anyone discovers exactly what the universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened.

I can't help but wonder exactly what Adams knew about quantum physics... :)

Re:Life, The Universe, & Everything

[Elder Entropist]

Something else that blew my mind with Douglas Adams' work and quantum:

In one of the books (Life the Universe, and Everything?) he explains about how the infinite improbability generator works, and he states that an artifical brain (Bambleweeney Vector Plotter?) is connected to a really hot cup of tea.

One of the problems with quantum computers is decoherence - isolating the qubits from the environment. I was reading an article where they were discussing a strategy for this by isolating the qubits in a fluid that had a strong random component to it, but where the many interactions averaged out to zero. A fluid with lots of brownian motion - in other words, a hot cup of tea would do.

Re:Those crazy Perl users have beaten them to it!

[wass]

I am working on a quantum computing simulation in Java as well, and it's been up for a few months now. So far I only have single-qubit operations, which are useful only in explaining how qubits act and how they differ from classical bits. The meat of quantum computation doesn't really kick in until you can have multiple qubits entangled.

Anyone interested can try it out here [jhu.edu]. You can take any valid input qubit, operate on it with any of six different single-qubit operators, and then see the output qubit. Qubits are represented as both complex spinors and on the Bloch sphere.

Next up is to add two-qubit operations, then work to having a controllable demo of quantum teleportation. I'd appreciate any constructive comments, if anyone would like to add some input.