Entropy, thermostats, and chaotic hypothesis.
The chaotic hypothesis is proposed as a basic for a general theory of nonequilibrium stationary states.
Journal Article↗
Biomedical subjects
Giovanni Gallavotti
Publications and source records attributed to Giovanni Gallavotti.
Entropy production and thermodynamics of nonequilibrium stationary states: a point of view.
Entropy might be a not well defined concept if the system can undergo transformations involving stationary nonequilibria. It might be analogous to the heat content (once called "caloric") in transformations that are not isochoric (i.e., which involve mechanical work): it could be just a quantity that can be transferred or created, like heat in equilibrium. The text first reviews the philosophy behind a recently proposed definition of entropy production in nonequilibrium stationary systems. A detailed technical attempt at defining the entropy of a stationary states via their variational properties follows: the unsatisfactory aspects of the results add arguments in favor of the nonexistence of a function of state to be identified with entropy; at the same time new aspects and properties of the phase space contraction emerge.
Entropy↗
Chaotic dynamics, fluctuations, nonequilibrium ensembles.
The ideas and the conceptual steps leading from the ergodic hypothesis for equilibrium statistical mechanics to the chaotic hypothesis for equilibrium and nonequilibrium statistical mechanics are illustrated. The fluctuation theorem linear law and universal slope prediction for reversible systems is briefly derived. Applications to fluids are briefly alluded to. (c) 1998 American Institute of Physics.
Journal Article↗