From: sarfatti@well.sf.ca.us (Jack Sarfatti)
Subject: FTL communication is kosher!
Organization: Whole Earth 'Lectronic Link
Date: Tue, 18 Aug 1992 08:05:15 GMT


How to really communicate from future to past!
From aephraim@physics.Berkeley.EDU Mon Aug 17 19:23:19 1992
Date: Mon, 17 Aug 92 19:22:46 PDT
From: aephraim@physics.Berkeley.EDU (Aephraim M. Steinberg)
To: sarfatti@well.sf.ca.us

Have you seen Viduguris's posting to usenet rephrasing the energy-
conservation argument, by the way? [NO! I HAVE NOT. I DON'T KNOW
HOW TO SEARCH THE 6000 ARTICLES EFFICIENTLY -SARFATTI]

You're right that I'm treating my beam splitters et cetera
essentially classically.  I'm not trying to say that a device such
as what you posit could never exist, but rather that at present
there is no reason to believe that any combination of known
physical or optical elements should behave in the manner you
describe, certainly not the calcite crystals and dielectric beam
splitters of your original design. Beam splitters do act the way I
have described, as far as any one currently knows, and the fact
that qm is nonlocal does not mean that we should reject all local
descriptions of common laboratory equipment!

Your mixing of actual experimental proposals with general
arguments that "such and such an effect could exist because (1) we
know some systems violate time-reversal invariance, (2) we know
nature is nonlocal, or (3) energy is stored in the vacuum and
perhaps some of it can be tapped" puts me in mind of a Greek
philosopher, who knows nothing of electricity, ions, quantum
mechanics, how to make good mirrors, et cetera, but who argues
that nothing he knows about the world proves that laser action is
impossible,and spends his life trying to come up with different
combinations of rock and papyrus that lase.

If you can start with the basic elements, and devise a beam
splitter that violates energy conservation in such a way as to aid
in your scheme (though I'm sure you're familiar enough with Nick
Herbert's proposals and the responses to them to know that you
"can't clone a photon," so actual gain will help you rather than
hurt you as far as quantum-mechanical correlations go), or even
one which acts "nonlocally" in the way you mention, such that the
phase difference is not pi/2, then maybe you'll stand some chance
of getting a result.

I mean, I've heard of people who study laser mirrors and FIND that
the pi/2 rule seems to be violated.  But until someone comes up
with a good theory that predicts such a thing, I have less faith
in their interpretation and experimental technique than in
"established" theory (I know, very un-PC of me).  If their results
stand, perhaps I'll change my mind.  But I'd look very closely at
their data and possible explanations before simply assuming that
such a beast exists and trying to figure out how to use it to
violate other long-standing principles of physics!

Excuse my rambling babbling.  It's been a long day, and sadly, one
which could have been spent almost as productively trying to build
beam splitters which tap the vacuum fluctuations.

aephraim

Sarfatti responds:
#1 In fact, I have suggested a precise way to make a beam splitter
in which, if there is no screening of the optical inhomgeneity in
the return path (d2) from back to front face of the plate, you are
going to observe a breakdown of time reversal invariance and a
perturbation of the vacuum fluctuations. I would bet however that
a screening effect prevents the latter amazing phenomena - though
I would wish they happen in some Borgesian super-tech parallel
interfering Feynman alternative "world".

#2 I agree that in the beam splitter mode the plate has shift of
pi/2. But by your same argument it is easy to prove that an ideal
50-50 beam recombiner i.e. two equal intensity inputs gives two
equal intensity outputs must have a net reflection phase
difference of B = 0. Here is the proof:

The output intensities are:
(t*T + r*R)(tT* + rR*) = |t|^2|T|^2+ |r|^2|R|^2 + r*tRT*+ rt*R*T
= |t|^4 + |r|^4 + 2|r|^2|t|^2 cos (b-B)
= |t|^4 + |r|^4 + 2|r|^2|t|^2 cos (pi/2-B)
= |t|^4 + |r|^4 + 2|r|^2|t|^2 sinB     for I1 and

(t*R + r*T)(tR* + rT*) = |t|^2|R|^2 + |r|^2|T|^2 + r*tR*T + r*tR*T
= |t|^2|r|^2 + |r|^2|t|^2 + 2|r|^2|t|^2 cos (b+B)
= |t|^2|r|^2 + |r|^2|t|^2 + 2|r|^2|t|^2 cos (pi/2+B)
= 2|r|^2|t|^2 - 2|r|^2|t|^2 sinB   for I2

when the input intensities are t*t into O1 and r*r into O2 (i.e.,
Experiment II in the recombiner mode) using your earlier notation. I
have accepted your time reversal symmetry argument that b is pi/2 for
one input of unit intensity into I1.

By the way it's easy to measure B operationally. Given a plate of
glass. First shoot one beam into I1 and measure the O1 and O2
intensities which are t*t = |t|^2 and r*r = |r|^2 respectively.
This gives us the ratio x = |r|^2/|t|^2 from Experiment I in the
beam splitter mode. Now do Experiment II in the recombiner mode
with two real (not imaginary time reversed) inputs (forward in
time) and measure the I1 and I2 output intensities. This gives the
ratio
z = |I2|^2/|I1|^2

  = [2|r|^2|t|^2-2|r|^2|t|^2 sinB]/[|t|^4+|r|^4+2|r|^2|t|^2 sinB]

= 2x(1 - sinB)/[1 + x^2 + 2sinB]

Remember these equations come from energy conservation! Suppose
the plate is a 50-50 "half-silvered" ideal beam splitter. This
means x = 1. Suppose this same plate is a perfect 50-50 beam
recombiner, so that z = 1. Therefore,

1 = 2(1 - sinB)/2(1 + sinB) so that sinB is 0. Hence B = 0 or pi
in which case cosB = 1 or -1 - not zero!

Yes, as a beam splitter with one actual input beam the relative
phase shift b of the outputs is pi/2 consistent with your
argument. But that same plate with  two actual equal intensity
input beams giving two equal intensity output beams has B = 0 say.

So now- back to the faster-than light communicator. Into I1 at the
transmitter comes [- e^iphi/sqrt2]|Eb>|Ea> (-sign from pi external
reflection at mirror, phi from the phase plate in the Ea path).
Note a is transmitter photon and b is receiver photon. Into I2
comes [1/sqrt2]|Ob>|Ea> since the half-wave plate in the Oa path
rotated the polarization by 90 degrees. Out of O1 comes the
superposition {[- e^iphi/2]|Eb>+[1/2]|Ob>}|Ea> into transmitter
counter 1. I have used B = 0But the far away receiver photon b
states are orthogonal <Eb|Ob> = 0 so the total response of counter
1 is 1/4+1/4 = 1/2. Similarly, for counter 2 which gets an
identical input! Thus, no local trace of phi at the transmitter
counters 1 and 2. But what's happening at the far away receiver
counters 3 and 4? Take the input into transmitter counter 1 and
resolve the b kets to the kets of the receiver crystal as photon b
interacts with it. Thus,

{[- e^iphi/2]|Eb>+[1/2]|Ob>}|Ea> ->

[- e^iphi/2]{cosx|eb>+sinx|ob>}+[1/2]{-sinx|eb> + cosx|ob>}|Ea>

= [-cosx e^iphi-sinx]|eb>|Ea>/2 + [cosx-sinx e^iphi]|ob>|Ea>/2

The eb path feeds to receiver counter 3. Thus the input from
transmitter counter 1 that is quantum connected to receiver
counter 3 has probability

p(3|1) = |[-cosx e^iphi-sinx]/2|^2 = [1 + sin2xcos(phi)]/4

similarly

p(4|1) = |[cosx - sinx e^iphi]/2|^2 = [1 - sin2xcos(phi)]/4

and p(3|1) = p(3|2) and p(4|1) = p(4|2) so that

p(3) = p(3|1) + p(3|2) = [1 + sin2xcos(phi)]/2

p(4) = p(4|1) + p(4|2) = [1 - sin2xcos(phi)]/2

Therefore, in conclusion, the faster-than-light (FTL) and,
possibly backwarss-in-time (BIT) quantum signal on the spin
connection is the parity-violating

p(3) - p(4) = sin2x cos(phi)

whre x is the misalignment of the two crystals at the events that
photons a and b pass them, and phi is the modulation variable
controlled by varying setting of phase plate at transmitter
between emissions of successive pairs.

And this is kosher! The world works this way. I guarantee it!