Fyzikální ústav Akademie věd ČR

Seminar Tuesday, 23/10/2012 15:00 - 16:00

Speakers: Christian Maes (Instituut voor Theoretische Fysica, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium)
Place: Na Slovance, main lecture hall
Organisers: Department of Condensed Matter Theory

Abstract: Relaxation to equilibrium has a witness: the thermodynamic entropy increases for thermally isolated systems to reach a maximal value characterizing the typical outlook of equilibria. That fact gets translated to the existence of Lyapunov functions (or H-functions) in physically motivated differential equations. An important example is the ever increasing H-functional in the theory of dilute gases following the Boltzmann equation, but more generally the idea of entropic forces leads to an understanding of close-to-equilibrium behavior. In this talk we ask the question what remains of such monotonicity for open driven systems. We present two types of candidates, one entropic, related to static fluctuations and the other, called frenetic, related to dynamical fluctuation theory. The main question is however to see what is their physical -operational- meaning. Do these monotone quantities correspond to real (nonequilibrium) thermodynamic forces? Do they essentially differ from equilibrium forces? We give examples for interacting particle systems (Markov processes) as studied also mathematically for studies of large deviations in the context of probability theory.