Re: Quantum entanglement and information transfer

From: Joe Rongen (joe_at_alpha.to)
Date: 07/22/04 

Date: 22 Jul 2004 05:16:44 -0400

"Caroline Thompson" <ch.thompson1@virgin.net> wrote in message news:<3KZJc.104$wq5.31@newsfe3-gui.ntli.net>...
[snip]

>There are some very neat sources of "photons" around these days
>that do seem to naturally support QM, but have they really proved
>that they were initially of random direction? It's not easy to tell the
>difference between a mixture of signals, some of one polarisation, some
>orthogonal, and a genuinely random set.

One can find a practical example here:

http://xxx.lanl.gov/abs/quant-ph?0404115

"We present an entangled-state quantum cryptography system that operated for
the first time in a real world application scenario. The full key generation
protocol was performed in real time between two distributed embedded
hardware devices, which were connected by 1.45 km of optical fiber,
installed for this experiment in the Vienna sewage system. The generated
quantum key was immediately handed over and used by a secure communication
application."