2002/12/12 by Hugo Touchette
Physics and Astronomy · #cond-mat.stat-mech
published as M. Gell-Mann, C. Tsallis (eds.), Nonextensive Entropy -- Interdisciplinary Applications, Oxford University Press, 2002 · 14 pages, 2 figures; contribution to the International Workshop on Interdisciplinary Applications of Ideas from Nonextensive Statistical Mechanics and Thermodynamics, April 8-12, 2002, Santa Fe Institute, Santa Fe, New Mexico, USA
arxiv created 2002/12/12 · arxiv updated 2009/11/30
It has been suggested recently that `q-exponential' distributions which form the basis of Tsallis' non-extensive thermostatistical formalism may be viewed as mixtures of exponential (Gibbs) distributions characterized by a fluctuating inverse temperature. In this paper, we revisit this idea in connection with a detailed microscopic calculation of the energy and temperature fluctuations present in a finite vessel of perfect gas thermally coupled to a heat bath. We find that the probability density related to the inverse temperature of the gas has a form similar to a χ2 density, and that the `mixed' Gibbs distribution inferred from this density is non-Gibbsian. These findings are compared with those obtained by a number of researchers who worked on mixtures of Gibbsian distributions in the context of velocity difference measurements in turbulent fluids as well as secondaries distributions in nuclear scattering experiments.