🚀 go-pugleaf

mbk@hamilton (Matt Kennel) writes:
>phfrom@nyx.uni-konstanz.de (Hartmut Frommert) writes:
>: matmcinn@nuscc.nus.sg (Mcinnes B T (Dr)) writes:
>: 
>: >[..]Does "gravity" propagate at the speed of light near
>: >a black hole?
>: 
>: To my knowledge, Einsteinian gravity waves always propagate at the same
>: velocity as "classical" light, i.e. mass- and structureless point particles
>: [which do not exist] along null geodesics.

[BTW: That's not the constant velocity c of course.]

>What's the speed of propagation of the Pauli exclusion "force"?

First of all, the fermions observing the Pauli exclusion are of course *not*
mass- and structureless point particles. So it is not trivial that 
Neutrinos, or even bosonic photons (which both have spin and NU's even weak 
SU(2) charge) propagate along null geodesics. So, as you indicated in the 
header, this is another subject.

In relativistic QFT the "Pauli Exclusion Force (PEF)" should propagate
with velocity no larger than c. This follows from the vanishing of 
anticommutators and cross section expectation values over spacelike 
intervals, i.e. causality.

>I.e. you have a macroscopic degenerate system.  All of a sudden one particle
>decays into other stuff (you measure the decay products and so localize the
>position of the ex-particle) and leaves a state free.  How long is it before
>the other side notices?

The sudden annihilation of one particle in the totally skew-symmetric fermion
Fock space is provided by an annihilation operator which does not touch the
antisymmetry of the system, i.e. the N fermion system is "transformed" to
a N-1 fermion system. Since [under not too strange assumptions] the laws of
Special Relativity stay alive, the time for the "other" particles to 
"notice" that process is certainly not greater than their distance to the 
annihilated one, divided by c. But I must leave a detailed demonstration
or outline of that to someone with more expertise in this field :-) .

>Would this be a physical effect of wavefunction "collapse"?

Left to the one called above :-)

 Hartmut Frommert                 <phfrom@nyx.uni-konstanz.de>
 Dept of Physics, Univ of Constance, P.O.Box 55 60, D-W-7750 Konstanz, Germany
                                           -- Eat whale killers, not whales --