Linked by Thom Holwerda on Fri 22nd Mar 2013 10:02 UTC
Hardware, Embedded Systems "But a powerful new type of computer that is about to be commercially deployed by a major American military contractor is taking computing into the strange, subatomic realm of quantum mechanics. In that infinitesimal neighborhood, common sense logic no longer seems to apply. A one can be a one, or it can be a one and a zero and everything in between - all at the same time. [...] Now, Lockheed Martin - which bought an early version of such a computer from the Canadian company D-Wave Systems two years ago - is confident enough in the technology to upgrade it to commercial scale, becoming the first company to use quantum computing as part of its business." I always get a bit skeptical whenever I hear the words 'quantum computing', but according to NewScientist, this is pretty legit.
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BeamishBoy
Member since:
2010-10-27

A one can be one or a zero or both. Not everything in between. It can't be a floating point 0.48294302. Quantum means a small discrete value.


It's been artlessly stated, but there's more than a grain of accuracy in that line. A qubit can have a range of possible values; the basic values it can assume are zero or one. Physicists would say that the qubit (let's call it |q>) can be in either the state |0> or the state |1>.

However, it can also be in a linear superposition of these states. Given any two complex numbers c and d, the qubit can be scaled to become:

|q> = c|0> + d|1>.

There are normalization requirements to make the probabilities sum to unity but this is just really basic linear algebra on a complex vector space. It's in this sense, the sense of a continuous range of possibilities for the superposition over basis vectors that I take the quote you mention to refer. In which case he's entirely accurate, if admittedly a little unclear.

Edited 2013-03-22 15:55 UTC

Reply Parent Score: 5

Bill Shooter of Bul Member since:
2006-07-14

Ok, I understand what you mean, and that's probably what they started from, but I disagree that the statement as written is accurate.

Reply Parent Score: 2