The European Physical Journal B

, Volume 61, Issue 1, pp 1–24

Heat and fluctuations from order to chaos


DOI: 10.1140/epjb/e2008-00041-1

Cite this article as:
Gallavotti, G. Eur. Phys. J. B (2008) 61: 1. doi:10.1140/epjb/e2008-00041-1


The Heat theorem reveals the second law of equilibrium Thermodynamics (i.e. existence of Entropy) as a manifestation of a general property of Hamiltonian Mechanics and of the Ergodic Hypothesis, valid for 1 as well as 1023 degrees of freedom systems, i.e. for simple as well as very complex systems, and reflecting the Hamiltonian nature of the microscopic motion. In Nonequilibrium Thermodynamics theorems of comparable generality do not seem to be available. Yet it is possible to find general, model independent, properties valid even for simple chaotic systems (i.e. the hyperbolic ones), which acquire special interest for large systems: the Chaotic Hypothesis leads to the Fluctuation Theorem which provides general properties of certain very large fluctuations and reflects the time-reversal symmetry. Implications on Fluids and Quantum systems are briefly hinted. The physical meaning of the Chaotic Hypothesis, of SRB distributions and of the Fluctuation Theorem is discussed in the context of their interpretation and relevance in terms of Coarse Grained Partitions of phase space. This review is written taking some care that each section and appendix is readable either independently of the rest or with only few cross references.


05.20.-y Classical statistical mechanics 05.70.Ln Nonequilibrium and irreversible thermodynamics 05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion 

Copyright information

© EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2008

Authors and Affiliations

  1. 1.Dipartimento di Fisica and INFNUniversità di RomaRomaItaly