[extropy-chat] Re: Time Travel

[scerir]

From: "Rob Wilkes"
> If there were a technology that could backtrack the "entropic" disassembly
> of human remains up to the time of death then the information could be
> captured. Is there some law of physics that precludes back-tracking
> entropy?

It depends. In microphysics, in example, you can create
"indistinguishability"
at the *end*, by erasing a single photon's path (interferometer), or at the
*beginning*, by erasing the positions of two independent sources. Notice
that in *both* cases you can (also) get entanglement (*), since entanglement
occurs by creating indistinguishabilility, in example, between two mutually
exclusive histories of, say, a photon. All that just means you can have an
effect going from the past to the future, but also you can create an effect
(here and now, by means of a simple choice) going from the future to the
past
(the so called "RPE" vs. "EPR"). Of course, human or macro issues are
different.
s.

(*) Entanglement is a magic word these days. With a simple
    operational meaning. A1 and A2 are atoms, emitting
    same kind of photons (same transition). If you put
    a 360° photon detector *exactly* in between A1 and A2,
    the detector does not know which of the two atoms
    emitted the photon. So you get the entanglement.
    Nothing special.