Nuclear Theory Seminars at Texas A&M: Spring 2005

Location: Cyclotron Building (434), Seminar Room


Friday, February 18, 3:00pm

Dr. D. H. E. Gross, Hahn-Meitner Institute, Berlin
Microcanonical Thermostatistics as Foundation of Thermodynamics

Abstract:

Conventional thermo-statistics addresses infinite homogeneous systems within the canonical ensemble. However, some 150 ears ago the original motivation of thermodynamics was the description of steam engines, i.e., boiling water. Its essential physics is the separation of the gas phase from the liquid. Of course, boiling water is inhomogeneous and as such cannot be treated by conventional thermo-statistics.

Then it is not astonishing, that a phase transition of first order is signaled canonically by a Yang-Lee singularity. Thus it is only correctly treated by microcanonical Boltzmann-Planck statistics. It turns out that the Boltzmann-Planck statistics is much richer and gives even analytical insight into the statistical mechanics of condensation or, complementary, fragmentation phenomena and especially into entropy.

In this talk I will give the physical meaning of entropy and present a new statistical interpretation of the second law. Eventually I will explain why there is a critical end-point for the liquid-gas phase-coexistence while there seem to be none for the solid-gas one. Then I will illuminate the deep and essential difference between "extensive" and "intensive" control parameters, i.e., microcanonical and canonical statistics, exemplified by rotating, self-gravitating systems.


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