Re: Has FTL communication really never been tested in this way?

On 17 Oct, 21:48, PostReplies <nom...@xxxxxxxxxxxxxx> wrote:
http://cosmiclog.msnbc.msn.com/archive/2007/07/17/274531.aspx

I know most physicists reject the idea of FTL communication but I'm
surprised the experiment described in this article wasn't carried out
years ago or has it? Wouldn't the existence or absence of an
interference pattern created by entangled beams of photons be a way to
receive a signal instantaneously?
I'm not a physicist, just an interested lay person.

We can look at this from a number of viewpoints. Looking at this
mathematically I can write down Maxwell's equations, I can then
perform a Lorenz transformation and I will still have Maxwell's
equations. The Universe still looks the same. I may write
Schroedinger's equation as

H = E an equation which is invariant under Lorenz transformation.
Quite clearly from this FTL communication is impossible.

How then does this seeming paradox arise? Basically because if
something were a million LY distant it would

a) Take a million years to set the experiment up.
b) H = E we will have 2 eigenvalues of H which differ by 1/
(10^6*365.25*24*3600) Hz. Hence although we have (instantly) changed
state the uncertainty principle prevents us from seeing it.

This question of the UP to me at any rate resolves the paradox.

- Ian Parker

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