# Re: TECH: Quantum Head Job

From: Mike Lorrey (mlorrey@datamann.com)
Date: Thu Oct 11 2001 - 15:13:25 MDT

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John Clark wrote:
>
> Mike Lorrey <mlorrey@datamann.com> Wrote:
>
> > This is true, but you didn't get my point. If two quantum entangled
> > objects have a rest state,
>
> I don't know what you mean by "rest state" when you're talking about
> spin or polarization or other things that can be entangled. Spin up
> is as likely as spin down, vertical is as likely as horizontal polarization.
>
> > then it doesn't matter how the flip lands, the act of
> > flipping is conveying information to the other end: that the coin is
> > being flipped (or not).
>
> I flip my coin, it's tails, doses this mean you flipped your coin or not?
> I have no way to tell.

Well, lets take a sample, where we have two BECs that are separated from
each other (they were once the same BEC). Normally, at any given moment,
you have a 50-50 odds on its spin being in one state, however when you
observe it, it remains in the state you observed for the period of time
it is being observed.

So I am trying to send you a '1' bit as opposed to an '0' bit. When you
are listening, you are observing every few planck time units, while I am
observing constantly. You record a pattern of UUUUUUUUUU in your
observations, which is a rather low probability series of observations
if the other end is not being observed (i.e. randomness), but if it is
observed, it is consistent with its state being maintained by constant
observation. Therefore, a random pattern of observations would mean the
other end isn't being observed, and a non-random pattern means the other
end is under constant observation (i.e. its state is being maintained).

So, therefore, the following series of observations:

UUUUUUUUUUYUYYUUYUYYUYUUYYYYYYYYYYYUUYUUUYYUYYYUUYUUUUUUUUUUUU
^--------^ ^---------^ ^---------^
observing not observ observing not observe observing ....

equates to a signal of 10101 being transmitted by the other end. Now,
there will obviously be bad 'bits' in there, of series of observations
in the same state for a number of consecutive observations, but this is
consistent with any noisy low bandwidth medium. The longer consecutive
number of observations that is set as a standard bit 'time' obviously
cleans things up but causes lower bandwidth, and you could also have to
deal with 'tell me three times' error checking or other error correction
schemes.

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