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Re: [Phys-l] Fwd: CMNS: Schrodinger pressure

A few more random thoughts on pressure, force etc. (just to keep the pot stirred)


On Jun 26, 2009, at Jun 26(Fri) 12:51 , John Denker wrote:

On 06/26/2009 07:38 AM, chuck britton wrote:

Back in the 'bad' old days - every pressure was associated with a force.

I don't see any fundamental force that was ever associated with
the pressure of an ideal gas

Very true. The ideal gas exerts its pressure thru elastic collisions with the container.
Kinetic Theory served me well until I was introduced to the Grand Canonical Ensemble etc.
The force of contact of the gas molecules is the same as the force of contact between my feet and the floor.

Contact Force was never listed as a 'Fundamental' force.
I was eventually told that I could call it the Pauli Exclusion force.
This made certain amount of sense.

But why was this Pauli Exclusion Force never related to the Four Fundamental Forces?


Fundamentally, this pressure is
associated with (i.e. is the derivative of) the kinetic energy
of the gas. Neither kinetic energy nor its derivative is listed
among the usual "fundamental" interactions.

and I suspect that every 'force' can be explicated as a suitable derivative of a suitable energy.
I'll even go so far as to suggest that the Pauli Exclusion Force is associated with he 'Exchange Energy' which shows up in many interesting Hamiltonians.

And there were 'Four' fundamental forces.

Slowly, but surely these forces are being reduced in number as they
are 'Unified'.

Which 'Force' would one tell an enquiring student that the
_degeneracy pressure_ is to be associated with?

It only applies to spin 1/2 (and integer + 1/2) particles - so is the
E&M force a good guess?

Not a good guess. The EM field (i.e. the photon) is spin 1. It's a
boson.


uh, as a good friend of mine would say TBI. (True But Irrelevant)
I'm not grasping this objection.
You're saying that the EM force doesn't apply to non-integer spin particles???


(Pauli Exclusion Force gets 957 google hits
Pauli Exclusion Pressure gets only 16)