The Statistical Interpretation of Non-Equilibrium Entropy

Abstract

Boltzmann's original scheme leading to the statistical interpretation of non-equilibrium entropy may be summarized as follows: Dynamics + Stochastic Process (kinetic equation) + Entropy. Recent computer experiments as well as spin echo experiments in dipolar coupled systems illustrate clearly the difficulties in Boltzmann's derivation. Indeed, they display situations for which a Boltzmann type of a kinetic equation is not valid. The main purpose of this communication will be to show that we can now construct a more general microscopic model of entropy which shows the expected mono-toneous approach to equilibrium even in non-Boltzmannian situations such as experiments involvinq "negative time evolution". First dynamic and thermodynamic descriptions of time evolution will be compared. The time inversion symmetry present in the dynamic equations is broken in the thermodynamic description (such as the Fourier equations). The relation between this symmetry breaking and causality will be discussed. Acta Physica Austriaca, SuppL X 26