Speed of Quantum information flow

Just wondering, in Quantum computing, how fast does information travel
between entangled particles? I would imagine it's 'c' but I can't
currently see why (if it wasn't 'c' then I guess it'd be more
common knowledge as the implication is that it'd be instant and that
would be big news). Guess I should have spent less time copying lecture
notes and more time understanding my Physics degree lectures, but then
that is a flaw common to most public education establishments.

Ooh, another thought, and what happens if the time frame in which one
of the entangled particles is relative to is different to the other
particle's reference frame? What if they're significantly different.
Hmmn, actually maybe that's not so difficult - I thought for a second
that there might be a paradox there but I'm unsure now.

Time has different meanings in quantum mechanics. Experiments in the
'60s show that entanglement seems to violate relativistic limitations,
but we're told not to worry because no information can be transferred
via entanglement.

A quantum computer might solve problems really, really quickly, but in
reading out the results, we are limited to the speed of light.

barney wrote:

Just wondering, in Quantum computing, how fast does information travel
between entangled particles? I would imagine it's 'c' but I can't
currently see why (if it wasn't 'c' then I guess it'd be more
common knowledge as the implication is that it'd be instant and that
would be big news). Guess I should have spent less time copying lecture
notes and more time understanding my Physics degree lectures, but then
that is a flaw common to most public education establishments.

Ooh, another thought, and what happens if the time frame in which one
of the entangled particles is relative to is different to the other
particle's reference frame? What if they're significantly different.
Hmmn, actually maybe that's not so difficult - I thought for a second
that there might be a paradox there but I'm unsure now.

barney wrote:

Just wondering, in Quantum computing, how fast does
informat=ADion travel between entangled
particles? I would imagine it's 'c'

You're confusing General Relativity with Quantum Physics. In QP, there
is no such concept as time. Particles should communicate
instantaneously, if you believe QP nonsense. The whole concept of a
Quantum computer is bogus: it would, at best, only deal in
probabilities. Each time you ask the same question, it would produce a
different result! Worse, if you observe the computer and think about
the answer, you will influence the output! Not a reliable way of
computing, if you ask me. I'm on the side of Einstein: although I can
see merit in some QP concepts, many of the QP ideas are just so nuts,
and many have yet to be proven. GR, on the other hand, has passed many
tests. If Albert continues to be right, information cannot travel
faster than c, even if the wavefront can.

Read this article for a really good laugh:
http://www.seti.org/site/apps/nl/con...b=3D194993&ct=
=3D343287

What Quantum computers? (What colonists on Mars!?)

Theoretically qp's would be instantaneous. Now go make us one.





barney wrote:

Just wondering, in Quantum computing, how fast does information travel
between entangled particles? I would imagine it's 'c' but I can't
currently see why (if it wasn't 'c' then I guess it'd be more
common knowledge as the implication is that it'd be instant and that
would be big news). Guess I should have spent less time copying lecture
notes and more time understanding my Physics degree lectures, but then
that is a flaw common to most public education establishments.

Ooh, another thought, and what happens if the time frame in which one
of the entangled particles is relative to is different to the other
particle's reference frame? What if they're significantly different.
Hmmn, actually maybe that's not so difficult - I thought for a second
that there might be a paradox there but I'm unsure now.

On 30 Jan 2005 15:22:06 -0800, "barney" wrote:


Just wondering, in Quantum computing, how fast does information travel
between entangled particles? I would imagine it's 'c' but I can't
currently see why (if it wasn't 'c' then I guess it'd be more
common knowledge as the implication is that it'd be instant and that
would be big news). Guess I should have spent less time copying lecture
notes and more time understanding my Physics degree lectures, but then
that is a flaw common to most public education establishments.

See Feynman's QED layman's book on Quantum Electrodynamics.

Photons (light particles) have non-zero amplitudes to travel both
faster than and slower than 'c'. At the (from a quantum mechanical
perspective) large distances we usually observe, however, those
probabilities become vanishingly small and hence we say that light
always travels at a constant speed 'c'. But at the subatomic scale
of things, the other amplitudes are significant.

Ooh, another thought, and what happens if the time frame in which one
of the entangled particles is relative to is different to the other
particle's reference frame? What if they're significantly different.
Hmmn, actually maybe that's not so difficult - I thought for a second
that there might be a paradox there but I'm unsure now.

The reference frame of two different particles is ALWAYS going to be
diferent. In classical relativity, now two distinct objects ever have
the same reference frame.

-Paul W.

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Now there you go, exposing the ugly parts of QED, stop that right now!
Feynman and others slaved for years to hide them, but mathematicians
still hold their noses when they see the totality of the "most
successful theory in the history of physics".

Paul Winalski wrote:

On 30 Jan 2005 15:22:06 -0800, "barney" wrote:


Just wondering, in Quantum computing, how fast does information travel
between entangled particles? I would imagine it's 'c' but I can't
currently see why (if it wasn't 'c' then I guess it'd be more
common knowledge as the implication is that it'd be instant and that
would be big news). Guess I should have spent less time copying lecture
notes and more time understanding my Physics degree lectures, but then
that is a flaw common to most public education establishments.


See Feynman's QED layman's book on Quantum Electrodynamics.

Photons (light particles) have non-zero amplitudes to travel both
faster than and slower than 'c'. At the (from a quantum mechanical
perspective) large distances we usually observe, however, those
probabilities become vanishingly small and hence we say that light
always travels at a constant speed 'c'. But at the subatomic scale
of things, the other amplitudes are significant.


Ooh, another thought, and what happens if the time frame in which one
of the entangled particles is relative to is different to the other
particle's reference frame? What if they're significantly different.
Hmmn, actually maybe that's not so difficult - I thought for a second
that there might be a paradox there but I'm unsure now.


The reference frame of two different particles is ALWAYS going to be
diferent. In classical relativity, now two distinct objects ever have
the same reference frame.

-Paul W.

----------
Remove 'Z' to reply by email.