F. Quarati1,* and P. Quarati2
1 Dipartimento di Fisica, Universitá di Cagliari, I-09042 Monserrato, Italy.
E-mail: [email protected]
2 Dipartimento di Fisica, Politecnico di Torino, Corso Duca degli
Abruzzi 24, I-10129 Torino, Italy, and Istituto Nazionale di Fisica Nucleare,
Sezione di Cagliari, I-09042 Monserrato, Italy.
E-mail: [email protected]
* Present address: Dept. of Physics and Astronomy, University of Glasgow, Scotland, U.K.
Received: 25 July 2002 / Accepted: 31 March 2003 / Published: 30 June 2003
Abstract:
We calculate the phase space
volumeoccupied
by a nonextensive system of N classical particles described by an equilibrium
(or steady-state, or long-term stationary state of a nonequilibrium system)
distribution function, which slightly deviates from Maxwell-Boltzmann (MB)
distribution in the high energy tail. We explicitly require that the number of
accessible microstates does not change respect to the extensive MB case. We also
derive, within a classical scheme, an analytical expression of the elementary
cell that can be seen as a macrocell, different from the third power of Planck
constant. Thermodynamic quantities like entropy, chemical potential and free
energy of a classical ideal gas, depending on elementary cell, are evaluated.
Considering the fractional deviation from MB distribution we can deduce a
physical meaning of the nonextensive parameter q of the Tsallis
nonextensive thermostatistics in terms of particle correlation functions (valid
at least in the case, discussed in this work, of small deviations from MB
standard case).
PACS codes: 05.20.-y, 05.70.-a
Keywords: Classical Statistical Mechanics, Thermodynamics.