X-Message-Number: 13988
Date: Thu, 22 Jun 2000 01:37:38 EDT
Subject: ligth "faster than ligth" and link with cryonics

In msg#13976 George Smith quotes:
 Wang emphasises that his experiments are relevant only to light and may not
 apply to other physical entities. But scientists are beginning to accept
 that man may eventually exploit some of these characteristics for
 inter-stellar space travel.
Here I see at least a way to do near instantaneous interstellar
communications. Assume we have a spacecraft near Alpha-
Centauri, 4.3 ligth years from the Sun (and us). With ordinary
communication channels, the round trip between an order and
the answer would be 8.6 years.

A way to short cut that time would be to use excited cadmium 113.
These nuclei have a metastable level disintegrating with an half
life near 14.6 year.

That is to say, when you excite them, you start to radiate a wave
packet whose the center (where the photon probability is concentrated)
is 14.6 LYrs from the packet head. You may display a configuration
able to concentrate the packet in the Alpha Centauri direction.
After 4.3 years, the wave packet hits the spacecraft, up to now,
nothing new. But then you use a small part of the photon probability
and move it, using an interference process, the the packet's head.
The spacecraft uses a quantum nondemolition process to detect
the partial probability without absorbing it, and induces another
interference sending back the photon probability in the solar system.

All of that takes place inside the wave packet and can be done without
speed limit. A polarization shift could define an information in either
move.The frequency of the photon is in the 10^20 Hz range and a
non zero probability zone may be some tens of wavelength long.
That alows to exchange a bit in 10^-18 second, that is this channel
has a band one billion gigabit wide. The channel remains open for
14.6 x 2 - 4.3 = 24.9 years. After that it become very difficult not
to send the full photon probability and the wave packet end up at
the Earth level. Well, another channel can be created before that
with other cadmium atoms.

I don't run SETI at Home screen saver because if there was some
ET civilization, it could not ignore that possibility. Tantalum 180
can generate some wave packets able to encompass all the
universe we see and beyond. If there is interstellar communications,
they must use these gamma rays, not the incredibly slow radio.

Because you must first wait for the head of the wave packet to
 reach its objective, there is no violation of the relativity
principle and no time paradox. At the limit the communication
is instantaneous, the answer can't find its way before the
question is asked.

Why write about that on cryonet?  I see a good reason:
That subject can motivate many people and the technology
has a large common trunk with the one exploited in a
brain reader. Unfortunately, ET and interstellar
communication are simpler to sell than uploading brains.

Yvan Bozzonetti.

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