

Code-breaking quantum algorithm run on a silicon chip  - edw519
http://www.newscientist.com/article/dn17736-codebreaking-quantum-algorithm-run-on-a-silicon-chip.html

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Estragon
This is interesting, and may have useful applications, but it's not a
validation of quantum computing as it's usually conceived, in that it appears
to be doing the computation with multiple photons, so it could be relying on
different photons being in different states. True quantum computing relies on
the Copenhagen interpretation of the current framework for Quantum Mechanics:
that the probability distributions it operates on are, in some sense, real,
rather than merely reflections of our uncertainty regarding the system's
state. It assumes that by operating on a superposition of these probability
distributions _within a single system_ , multiple computations can be
performed simultaneously. In the system described, that apparent superposition
in the probability distributions is potentially being "faked" by superposition
in the concrete, individual states of the multiple photons involved in the
computation.

But I'm biased. I'm quite dubious about the Copenhagen interpretation of
Quantum Mechanics, and I think quantum computation is a _reductio ad adsurdum_
of its conclusions, which may one day be used in its experimental disproof.

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hughprime
This _is_ a validation of quantum computing as normally conceived. Photons are
just as valid a quantum particle as anything else -- most importantly they can
exhibit entanglement, which classical "light waves" can't.

~~~
Estragon
You're begging the question. I'm aware that most physicists believe photon
states can be entangled. My point is that it's not clear that quantum
entanglement is used in this computation. There are so many photons being used
that it would be possible for the probability waves to be approximated by the
frequency distribution of the photons' states.

