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starship-design: Re: More Symmetry Stuff

Timothy van der Linden wrote:

> >>What about black-holes? Aren't they coherent enough?
> >
> >Actually, (According to Mr. Price) they aren't.  In our forward-time
> >view, we wouldn't expect two photons converging on a black hole (coming
> >from different directions) to be correlated in any way.  However, two
> >photons emitted from a common source ARE considered to be correlated.
> >This is a time-asymmetric assumption; viewed in the opposite time-
> >direction the reverse would be true.  Although we see the evidence of
> >this asymmetry all around us, there is no time-asymmetric law of physics
> >to explain it, and it is probably a result of the special boundary
> >conditions of Big Bang.
> >
> >A coherent radiation sink would have correlations between all incoming
> >particles.  The correlation would be a result of their common Future,
> >although they would have no common Past.
> Am I missing something? These seem to be exactly the properties of photons
> being absorbed by a black hole. They often don't have a common past, but
> they are likely to have a common future somewhere inside the black hole.

I think you are missing something here Tim.  Although most of this
discussion is as far above my head as Tau Ceti,  I think I understand
Ken here.  

Imagine you are at a black hole (far enough away to avoid nasty gravity
and you are assinged to count and catalog the photons that enter its
event horizon.
(so much for the glamour of being a cadet at the starfleet acadamy  ;)

Anyway, the first event you record is two photons arriving from
different directions and they just happen to have the same wavelength,
and are traveling in phase (even though by an estimate of their starting
positions you calculate they originated 10 light-years apart)  both are
absorbed by the black hole (or at least you assume they have, since you
never get to actually observe the crossing over) "what a strange
coincidence" you say to yourself.  Oh well, here comes the next photon. 
correction, make that photons.  again, there are two more originating in
different parts of the universe, traveling in phase, and having the same
wavelenth (although they are a different wavelength than the first
pair.)  how long before you begin to suspect that this is more than

Congratulations, you have just witnessed the first coherent radiation
sink.  For all time, these will be known as "van der Linden black holes"

> >We are used to seeing
> >correlations as a result of a common past, although viewed in the right
> >way the strange phenomenon of quantum mechanics can be seen as evidence
> >that certain correlations can be caused by a common future.  So a
> >coherent radiation sink would be very different from a black hole.
> >

Kind of like the article in the recent Scientific American about how to
observe a particle WITHOUT affecting it? (don't yell at me about how
this isn't possible, 
until you read "Quantum Shell Game" in the November 1996 issue of
Scientific American)

> >>Hmm, how do you get the mass out of the radiation sink (and into the
> >>conventional engine)? Would that not spoil the fun?
> >
> >Good point.  I suppose it all depends on what sort of object our
> >coherent absorber would be, and whether it would be possible to use
> >reverse-causal mass in a forward-causal engine.  I've been thinking
> >about this a little more and have come to a strange conclusion, based on
> >CPT symmetry.  CPT symmetry is a physical principle (in both quantum and
> >relativity) that any system with opposite Charge, opposite Parity
> >(mirror-image), and opposite Time-direction, must act exactly like the
> >original un-reversed system.  This would mean that if there was some
> >form of matter causally propagating backwards in time, it would most
> >likely be (mirror-image) antimatter.  The Big Crunch, when viewed from a
> >CPT-symmetrical standpoint, would then look exactly like the Big Bang,
> >with the same amount of antimatter then as we have matter today.
> >
> >The strange thing, though, is that the future boundary conditions would
> >not allow this backward-time antimatter to annihilate with forward-time
> >matter.  The antimatter Couldn't annihilate (in our temporal frame),
> >because it's constrained to exist at the end of the universe!  But this
> >would mean that antimatter "created" at the Big Crunch would be very
> >different from the antimatter that we create in particle accelerators.
> Aren't you looking at the problem with "forward-time"-view? It may be that
> (mirror-image) antimatter annihilates with our forward-time matter, but that
> in the future some effect (yet not know by us temporal creatures) creates
> antimatter once again.
> (If this makes no sense, it may be because I've lost track of all the
> mirrors, forward/backward, anti/matters.

How about this:

NB for best results, you must view this with a fixed width font.

a simple diagram:  M= matter propagating forward in time
                   A= antimatter propagating backward in time
                  EE= Event Energy (annihilation)
                  ><= indicate "true" direction of propagation


^     M                                      A
|       .>                                <.
|         .>                            <.
S           .>                        <.
p             .>                    <.
a               .>                <.
c                 .>            <.
e                   .>        <.
|                     .>    <.
|                       .><.
V                        EE

>From the view of us temporal limited creatures, a particle of Matter was
exchanged for a particle of Antimatter.  Don't ask me how charge
conservation is maintained, I'm simply trying to make this
understandable.  I suppose that for the universe as a whole, charge
conservation is maintained, or you might try to bring some virtual
particles into this to balance it all out.

Kevin "Tex" Houston 		http://umn.edu/~hous0042/index.html
Webmaster			http://www.urly-bird.com/index.html
"Whoever undertakes to set himself up as a judge of Truth and
Knowledge is shipwrecked by the laughter of the gods." A. Einstein