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Re: Particle Position



At 06:21 AM 5/10/99 -0500, my friend, Jack wrote:

| So in order for Jim's question to have meaning, he has to tell us what
|he means by a "particle".

Ok, Jack: I have a tendance to ask generalized questions -- I think that I
learn more that way, but let me give a specific example:

Consider an ideal gas of N "particles" in a box (sides L) with total energy
E -- How do I count the number of available states?

Some texts (eg Stowe, big Rief, and I think Kittel -- but I can't find my
copy just now) do a Byzantine calculation based on Heisenberg or wave
packets -- something like each particle (or each state) occupies a volume
of DxDyDzDpxDpyDpz in 6-dimensional phase space. And get something like

Omega = (1/h^3)V(real) V(momentum)

I guess my problem is that I am uncomfortable saying that the particles are
restricted to the resulting 6-d grid -- Why can't a particle be at say
(1/3),(1/8), 1/7), etc in the cell? Why should I assume that the particles
are centered in their cells?

Am I making any sense -- or am I just old and senile and am having a mental
block?

Jim Green
mailto:JMGreen@sisna.com
http://users.sisna.com/jmgreen