archiv~1: Re:SETI ETI Quantum Communication]

Re:SETI ETI Quantum Communication]

Wayne Shanks ( )
Mon, 02 Nov 1998 01:42:32 -0500 wrote:
> ---------------------------------------------------------------
> Subject: Re: SETI ETI Quantum Communication
> Date: Fri, 30 Oct 1998 18:42:06 EST
> From:
> To:
> In a message dated 10/30/98 10:33:56 AM Eastern Standard Time,
> writes:
> > Once again, someone stuff me back in my place here if I am wrong, BUT...
> >
> > I believe that this "quantum teleportation" would not transmitt any faster
> > or farther than normal RF communications. Light is just another form of
> > radiation. It travels through a medium at the speed of light for that
> > medium. The method used to transfer the information for the object (its
> > properties) was a laser. Thus, the limitations of the range and speed for
> > transfering that object are those of the laser (light).
> No, RJ, I believe that you are incorrect on this one. One of the strange
> things about quantum particles is their ability to stay connected at seemingly
> large distances. Bell's theorem would possibly allow faster than light
> communication by exploiting quantum particle effects.
> Not a physicist, but that's my interpretation.
> John Marcus.

Sory John... Your interpretation of Bell's theorem is not correct. It
is true that particles can remain "entangled" over large distances, but
there is no(none, ZIPO) information content in the streem of particles
recieved by the "reciever". All the information is encoded the
entanglement pair, so you must have information about both particles to
decode the seemingly random stream of spins, polorizations, or what ever
quantum atribute that you choose to use.

The sender sends a streem of particles that are entangled with a
collection of sister particles. The sent particles take some lenght of
time to traverse the communication distance. just before a particle
enters the recievers detector the sender measures the sister particle
thus fixing the state of the particle in transit. The sender is not
able to controll the state of the particle pair, but he is able to flip
the value of one of the pair. The reciever just gets a string of random
bits. Indeed there is zero information in this string of bits. It is
only by comparing the senders particle measurements to the recievers
measurements that the informatin can be decoded, thus the reciever has
to wait for a signal to traverse the large distance between the sender
and reciever before he can know how to decode the origional data stream.

You are still limited by the speed of light if you want to send a

Bell's theorem does not violate the principle that no information can
travel at faster than the speed of light.

Bell's theorem, or more to the point Bell's inequality gives a way to
test if reality is realy non-local, or local.

All current tests have violated the inequality signifying that the
universe is in fact non-loacal.

You can't communicate faster than light, but you can have a absolutely
secure/unbreakable communication. Quantum cryptography exploits
non-locality to give a secure communication, but it is very delicate and
easily scrambled so that nobody can decode it.

Wayne S