Some Scientists Question Whether Quantum Computer Really Is Quantum

gbrumfiel writes "Last week, Google and NASA announced a partnership to buy a new quantum computer from Canadian firm D-Wave Systems. But NPR news reports that many scientists are still questioning whether new machine really is quantum. Long-time critic and computer scientist Scott Aaronson has a long post detailing the current state of affairs. At issue is whether the 512 quantum bits at the processor's core are 'entangled' together. Measuring that entanglement directly destroys it, so D-Wave has had a hard time convincing skeptics. As with all things quantum mechanical, the devil is in the details. Still it may not matter: D-Wave's machine appears to be far faster at solving certain kinds of problems (PDF), regardless of how it works."

Comments

Re:D-Wave's Dirty Little Secret

[JoshuaZ]

Is there really any difference between quantum entanglement and magic?

Yes. There's this tendency to view entanglement as spooky, magical, and hard to understand. But this really isn't the case and is more due to the confusing way that quantum mechanics if often taught, as a series of counterintuitive results tacked on to classical physics. If one adjusts one's perspective to think of quantum mechanics more as the consequences of using a 2-norm and looking then at the structure imposed on vectors by unitary transformations, things make a lot more sense. Scott Aaronson(mentioned in the summary above) has a book out recently on just this subject "Quantum Computing since Democritus" which is aimed at explaining these issues to people outside is field but with a comfortable background in other technical fields- essentially no more than some linear algebra, basic probability and complex numbers. The book is highly readable and Scott is a very funny writer, so there are a lot of amusing asides.

Re:It's much cooler if we *don't* know how it work

[gestalt_n_pepper]

Anything can be pushed to the limits of what we know, and on occasion, things work, but not for the reasons you think it did. This is sufficiently close to the cutting edge that it may be operating correctly, but that we only think we understand why.

F'rinstance, for years, we thought about electricity as a liquid. Voltage equaled pressure. Amps equaled volume. The math worked. Nature wiggled it's eyebrows suggestively.

BUT, electricity is NOT a liquid. It works the way it does for completely different reasons. It just took a while for us to figure that out. Yet, even before we understood this, we build practical machinery.