| Topic: |
Science > Physics |
| User: |
"Sam Wormley" |
| Date: |
03 May 2007 10:35:50 PM |
| Object: |
Entanglement dies a sudden death |
Entanglement dies a sudden death (May 1)
http://physicsweb.org/article/news/11/5/1
A strange quantum phenomenon that could be a stumbling block to building
quantum computers has been observed for the first time by physicists in
Brazil. Known as entanglement sudden death (ESD), it involves the rapid
decay of the "entangled" pairs of particles that will be central to the
operation of quantum computers. Since the particles decay so quickly,
the physicists claim that the decay cannot be reversed using the
error-correction schemes that have been proposed to increase the
lifetimes of entangled particles (Science 316 579).
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| User: "BillMays" |
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| Title: Re: Entanglement dies a sudden death |
03 May 2007 11:06:30 PM |
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"Sam Wormley" <swormley1@mchsi.com> wrote in message
news:qSx_h.94600$_c5.93499@attbi_s22...
Entanglement dies a sudden death (May 1)
http://physicsweb.org/article/news/11/5/1
A strange quantum phenomenon that could be a stumbling block to
building
quantum computers has been observed for the first time by physicists in
Brazil. Known as entanglement sudden death (ESD), it involves the rapid
decay of the "entangled" pairs of particles that will be central to the
operation of quantum computers. Since the particles decay so quickly,
the physicists claim that the decay cannot be reversed using the
error-correction schemes that have been proposed to increase the
lifetimes of entangled particles (Science 316 579).
knew it.
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| User: "David Bernier" |
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| Title: Re: Entanglement dies a sudden death |
04 May 2007 06:27:20 PM |
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Sam Wormley wrote:
Entanglement dies a sudden death (May 1)
http://physicsweb.org/article/news/11/5/1
A strange quantum phenomenon that could be a stumbling block to
building
quantum computers has been observed for the first time by physicists in
Brazil. Known as entanglement sudden death (ESD), it involves the rapid
decay of the "entangled" pairs of particles that will be central to the
operation of quantum computers. Since the particles decay so quickly,
the physicists claim that the decay cannot be reversed using the
error-correction schemes that have been proposed to increase the
lifetimes of entangled particles (Science 316 579).
I think this
http://arxiv.org/abs/quant-ph/0701184
links to a preprint by the physicists in Brazil about their
experimental results.
In their Fig. 2b, I guess the solid red line shows C=0 when
p = 1/sqrt(3) ~= 0.577 .
David Bernier
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| User: "David Bernier" |
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| Title: Re: Entanglement dies a sudden death |
04 May 2007 07:21:37 AM |
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Sam Wormley wrote:
Entanglement dies a sudden death (May 1)
http://physicsweb.org/article/news/11/5/1
A strange quantum phenomenon that could be a stumbling block to
building
quantum computers has been observed for the first time by physicists in
Brazil. Known as entanglement sudden death (ESD), it involves the rapid
decay of the "entangled" pairs of particles that will be central to the
operation of quantum computers. Since the particles decay so quickly,
the physicists claim that the decay cannot be reversed using the
error-correction schemes that have been proposed to increase the
lifetimes of entangled particles (Science 316 579).
There was a debate around December 2005 between Leggett and
Ramsey in Berkeley, two Nobel prize winners in physics.
See e.g.:
http://www.nytimes.com/2005/12/27/science/27eins.html?ex=1293339600&en=caf5d835203c3500&ei=5090
In:
http://physicsweb.org/articles/world/18/3/5
Markus Arndt and Anton Zeilinger from the Institute for Experimental
Physics, University of Vienna, Austria write
about ``Disappearing fringes" as the environment interacts more
and more with the the quantum system which initially is
in a "superposition of different states".
cf.:
http://physicsweb.org/articles/world/18/3/5/1/PWqua4%5F03%2D05
figures (a) and (b).
Also, the section "Decoherence in a molecule interferometer"
at
http://physicsweb.org/articles/world/18/3/5
is an explanation in words of figs. (a) and (b)
referred to just above.
From the section ``Nine Ways of Killing a Cat" in the New York
Times article, it appears that experts disagree about
"what happens at the magic moment when a particle
is measured or observed." [ NYT wording, many-worlds, pilot-waves,
decoherence, modified Schroedinger equation, ...].
I couldn't access:
http://physicsweb.org/article/news/11/5/1
so I'm wondering what the basic set-up was.
Also, has the Brazilian experiment been done
elsewhere?
If not, perhaps some will be interested in trying to
replicate it.
David Bernier
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