First Evidence That Google's Quantum Computer May Not Be Quantum After All 224
KentuckyFC writes "In May last year, Google and NASA paid a reported $15 million for a quantum computer from the controversial Canadian start up D-Wave Systems. One question mark over the device is whether it really is quantum or just a conventional computer in disguise. That's harder to answer than it sounds, not least because any direct measurement of a quantum state destroys it. So physicists have to take an indirect approach. They assume the computer is a black box in which they can input data and receive an output. Given this input and output, the question is whether this computing behavior can be best reproduced by a classical or a quantum algorithm. Last summer, an international team of scientists compared a number of classical algorithms against an algorithm that relies on a process called quantum annealing. Their conclusion was that quantum annealing best reproduces the D-Wave computer's behavior, a result that was a huge boon for the company. Now a group from UC Berkeley and IBM's Watson Research Lab says it has a found a classical algorithm that explains the results just as well, or even better, than quantum annealing. In other words, the results from the D-Wave machine could just as easily be explained if it was entirely classical. That comes on the back of mounting evidence that the D-Wave computer may not cut the quantum mustard in other ways too. Could it be that Google and NASA have forked out millions for a classical calculator?"
Quantum Cash! (Score:3, Insightful)
Why buy something that isn't demonstratively faster than the old stuff...
I mean if the difference is so small that there is some sort of debate about if it is effectively working or not, then it seems to me at that point cost should be the deciding factor. I doubt these D Wave machines are any cheaper than the old stuff.
Who cares? (Score:3, Insightful)
Re:Who cares? (Score:1, Insightful)
Obviously, you don't have a use for a quantum computer if you can't find a way to determine if it's a quantum computer. If it's just speed, what you want is a super-computer. If it's the ability to perform certain calculations, they simply don't work on a classical computer (or take eternity, even for a super-computer).
Thanks for your insightful input. We do not understand this computer stuff. Is it true that red leds won't make our P-III server run any faster?
Google
Re:Would D-Wave Take That Risk? (Score:5, Insightful)
Even better, at least one group of smart people was fooled, and it took a group from UC Berkeley and IBM's Watson Research Lab to show a plausible classical algo. If it is fraud, it is well executed. That makes me believe they actually do have a crappy quantum computer, or believe they do.
And, with an actual product, people are hammering on it in ways that will prompt quant research into being able to prove or disprove how it works. Fraud or not, its a boon to everyone who didn't pay for it directly.
Re:Quantum Cash! (Score:3, Insightful)
Suppose someone tried to sell you a "horseless carriage" that was pulled by a big black box. You insert hay and oats into one side of the black box, then it goes "clop-clop-clop" and pulls the carriage at about the speed of an old horse in a big black box. If you watched closely enough, you'd observe horse turds falling out of the back of the box. That, so far, is what D-Wave's "quantum computer" looks like to astute outside observers. How much are you going to pay to be on this "leading edge" of carriage technology?