Pérez Madrid, Agustín2012-04-262012-04-2620070022-2488https://hdl.handle.net/2445/24584In this Contribution we show that a suitably defined nonequilibrium entropy of an N-body isolated system is not a constant of the motion, in general, and its variation is bounded, the bounds determined by the thermodynamic entropy, i.e., the equilibrium entropy. We define the nonequilibrium entropy as a convex functional of the set of n-particle reduced distribution functions (n ? N) generalizing the Gibbs fine-grained entropy formula. Additionally, as a consequence of our microscopic analysis we find that this nonequilibrium entropy behaves as a free entropic oscillator. In the approach to the equilibrium regime, we find relaxation equations of the Fokker-Planck type, particularly for the one-particle distribution function.10 p.application/pdfeng(c) American Institute of Physics, 2007Mecànica estadísticaProcessos estocàsticsEntropiaTermodinàmicaEquació de Fokker-PlanckStatistical mechanicsStochastic processesEntropyThermodynamicsFokker-Planck equationinfo:eu-repo/semantics/article558293info:eu-repo/semantics/openAccess33321739