Under the Hood of Quantum Computing

nanotrends writes "Gordie Rose, the CTO of Dwave Systems, the venture funded company that plans to offer paid use of a superconducting quantum computer starting in 2007, reveals secrets of his quantum computer construction. It is based on nobium superconducting 'circuits of atoms' and is not RSFQ. (Rapid Single Flux quantum)."

Comments

Re:Advantages?

[Mathinker]

Uhm, from the article, nobody can even assess whether it really is a quantum computer.

Woo Woo science

[Valacosa]

A functional quantum computer? Really?

I used to be a undergrad lab assistant. I never worked in quantum computing, but our neighbours were some of these guys. I picked up a few things, one of those things being that quantum computing is hard.

Classical computers use the laws of classical physics to operate. Classical physics is deterministic, and that's how we want our classical computers to behave. As the chip and die sizes get smaller and smaller (what are we at now, 65nm?) CPUs are more likely to suffer from quantum effects, but AFAIK there's circutry in there to compensate for that. Error checking.

A quantum computer is just a machine that uses the laws of quantum mechanics rather than the laws of classical mechanics to operate. The advantage is that some algorithms, when implemented on a quantum computer, are 2n instead of n^2. I never really understood this, maybe a better physicist will come along and explain it. Anyway, to build a quantum computer one needs two things:
- (a) You need some Quantum bits (qbits) to store data
- (b) You need to get those bits to interact with each other in some fashion

There are many approaches to building a quantum computer. One guy (Raymond Laflamme) has a bunch of different atoms that are different elements all in the same molecule, those interact with each other but he has only developed the ability to read / write to about 5 different qbits. I read about another guy on Slashdot here who made a giant array of qbits using atoms in a laser trap. That gets you a lot of qbits, but they don't interact at all. There are many approaches.

Anyway, the reason I think Dwave Systems is full of bullshit is that any approach thus far is good at (a) or (b), but not both. Someone who got a powerful quantum computer up and running would most assuredly win a Nobel Prize. Also, why the hell would he need to woo venture capital? I know I'm up in Canada, but I'm sure most governments are throwing scads and scads of research money at Quantum computing. Answer? Venture capitalists are more naive.

If there's anything I learned from here, it's that a lot of Con artists use buzzwords to try and justify their woo-woo science. "Quantum" is one of them.

Smart money on this guy being a fraud.

Re:Woo Woo science

[Valacosa]

You're half right. I had forgotten about the quantum properties of transistors.

Though a transister does use Quantum Mechanics to function, it is a discrete unit (a "black box" if you will) with a preidctable outcome. A quantum computer, on the other hand, uses a property of QM known as "superposition of states". A qbit in a quantum computer isn't 0 or 1, but some combination of 0 and 1 at the same time. It's only when the qbit is "observed" (read) that it becomes a 0 or 1.

If we can get these qbits to interact with each other without reading them (or "collapsing the wavefunction", in quantum mechanics lingo) then we can have various superpositions of 0s and 1s interacting with each other within an algoritm. Essentially the algorithm run by the quantum computer is acting in parallel with itself. When we observe the qbits when the algoritm is finished, we see the desired result. I know that sounds like magic, but I've probably explained it poorly. I've explained it better in the past.

Incidentially, someone who is uneducated (not stupid, mind you, just uneducated) may have difficulty distinguishing between the BS in the original article and the more scientifically accepted BS I've spouted. See? That's how these con artists are allowed to succeed!