Re: Polarizing communicators

Michael Lorrey (retroman@tpk.net)
Mon, 28 Apr 1997 18:39:48 -0400

John K Clark wrote:
>
>
> Some atoms produce 2 photons of the same polarization but traveling in
> opposite directions, so if you measure the polarization of one you know the
> polarization of the other. A billion years before I was born somebody in the
> Virgo Cluster started making pairs of such photons that have identical but
> unknown polarization. He sent one stream of photons to the earth, a billion
> light years away, he sent another stream of photons to the Coma cluster in
> the opposite direction from the earth a billion and one light years away.
> A billion years later on Earth I spin my polarizer to a random direction,
> record the position, observe if the photon made it through the detector or not
> (a 50, 50 chance) then record that too. Now I spin the polarizer again and do
> the same thing for the next photon (again a 50, 50 chance) and then for the
> next several thousand photons. I know that a year from now a friend of mine
> in the Coma Cluster will perform the exact same experiment on his stream of
> photons and I decide to visit him. I get in a space ship with my records and
> blast off for the Coma Cluster at 99% of the speed of light.
>
> After 2 billion years I arrive in the Coma Cluster and compare notes with my
> friend. I notice that the direction I had my polarizer turned to and the
> direction my friend had his turned to were different, not very surprising
> since both were picked at random, but then I find something astounding,
> the square of the cosign of the angle between the 2 detectors for each photon
> is proportional to the probability that a photon will make it through my
> friend's detector.
>
> I have instantly changed something that is 2 billion light years away and was
> made long before dinosaurs walked the earth. Pretty weird. Unfortunately this
> effect can not be used for faster than light communication because before I
> arrived with my records the results of my friends experiment looked random
> to him, it's only when he compared his results with my records, and that can
> only be done at the speed of light or less, did it become obvious that
> turning my polarizer and observing the results instantly changed his photons
> far away. Nevertheless this does have a practical benefit, you can use it to
> make a communication link that is absolutely secure, it's already been done
> and not just in the lab. Recently two banks in Switzerland used Quantum
> Cryptography to send secure financial data to each other.

Here's a concept: If you send out a message, repeating itself so anyone
can tune in at any time to get the gist, that basically tells them to
focus their polarizers on this source, and a set pattern of H and V
alternations with a polarizer, can't you use that to set up a carrier
wave with which you can communicate by putting signals on top of the
carrier wave? if you know what the normal pattern is ahead of time,
shouldn't you be able to use induced abberations in the pattern as a
signal?
>
> John K Clark johnkc@well.com
>
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-- 
TANSTAAFL!!!
			Michael Lorrey
------------------------------------------------------------
mailto:retroman@tpk.net		Inventor of the Lorrey Drive
Agent Lorrey@ThePentagon.com
Silo_1013@ThePentagon.com	http://www.tpk.net/~retroman/


Mikey's Animatronic Factory
My Own Nuclear Espionage Agency (MONEA)
MIKEYMAS(tm): The New Internet Holiday
Transhumans of New Hampshire (>HNH)
------------------------------------------------------------
#!/usr/local/bin/perl-0777---export-a-crypto-system-sig-RC4-3-lines-PERL
@k=unpack('C*',pack('H*',shift));for(@t=@s=0..255){$y=($k[$_%@k]+$s[$x=$_
]+$y)%256;&S}$x=$y=0;for(unpack('C*',<>)){$x++;$y=($s[$x%=256]+$y)%256;
&S;print pack(C,$_^=$s[($s[$x]+$s[$y])%256])}sub S{@s[$x,$y]=@s[$y,$x]}