Journal of Experimental and Theoretical Physics
HOME | SEARCH | AUTHORS | HELP      
Journal Issues
Golden Pages
About This journal
Aims and Scope
Editorial Board
Manuscript Submission
Guidelines for Authors
Manuscript Status
Contacts


ZhETF, Vol. 120, No. 1, p. 214 (July 2001)
(English translation - JETP, Vol. 93, No. 1, p. 188, July 2001 available online at www.springer.com )

BIG ENTROPY FLUCTUATIONS IN STATISTICAL EQUILIBRIUM: THE MACROSCOPIC KINETICS
Chirikov B.V., Zhirov O.V.

Received: November 20, 2000

PACS: 05.45.Gg, 05.40.-a

DJVU (164K) PDF (718.4K)

Large entropy fluctuations in the equilibrium steady state of classical mechanics are studied in extensive numerical experiments in a simple strongly chaotic Hamiltonian model with two degrees of freedom described by the modified Arnold cat map. The rise and fall of a large separated fluctuation is shown to be described by the (regular and stable) «macroscopic» kinetics, both fast (ballistic) and slow (diffusive). We abandon a vague problem of the «appropriate» initial conditions by observing (in a long run) a spontaneous birth and death of arbitrarily big fluctuations for any initial state of our dynamical model. Statistics of the infinite chain of fluctuations similar to the Poincaré recurrences is shown to be Poissonian. A simple empirical relation for the mean period between the fluctuations (the Poincaré «cycle») is found and confirmed in numerical experiments. We propose a new representation of the entropy via the variance of only a few trajectories («particles») that greatly facilitates the computation and at the same time is sufficiently accurate for big fluctuations. The relation of our results to long-standing debates over the statistical «irreversibility» and the «time arrow» is briefly discussed.

 
Report problems