Re: SMD and CPT? (fwd)

From: Sterling Paramore (
Date: Fri Feb 09 2007 - 16:08:38 CST


Well, I'd like to keep the First Law no matter what. So I'd say that
for adiabatic extension, however the energy changed should be exactly
equal to the work. I would think that it would end up being \int F*d,
but I could be wrong.


Marcos Sotomayor wrote:

> Hi Sterling,
> Let me be more specific. First, when the external force applied to
> your system is time-dependent, the Hamiltonian of your system is not
> conserved anymore and does not represent the total energy. Moreover,
> the expression F \times d, as far as I can tell, is no longer the work
> done on the system (usually one assumes a time independent
> hamiltonian/force to derive that expression). So my sentence should
> have read like: " The quantity F \times d (previously work done)
> should only be similar to the energy change". Please correct me if I
> am wrong on that.
> I think you are right in that the total amount of work done by the
> external force does match the energy change, but you cannot use Fd to
> measure it. Therefore, the first law of thermodynamics is not
> violated. There is a nice article on a similar topic that you may want
> to check:
> "Invariants for time-dependent Hamiltonian systems"
> Jurgen Struckmeier and Claus Riedel
> Physical Review E 64 026503
> Regards,
> Marcos

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