What is nonequilibrium?
arXiv:2601.16716
Abstract
Lecture notes on elements of nonequilibrium statistical mechanics: (1) a characterization of the nonequilibrium condition, largely by contrast to equilibrium; (2) a retelling of some of the great performances of the more distant past, including the perspectives of Boltzmann and Onsager; and (3) more recent methods and concepts, from local detailed balance and the identification of entropy fluxes to dynamical fluctuation theory, and the importance of dynamical activity.
About 100 pages of introduction to nonequilibrium stuff. Updates available via https://fys.kuleuven.be/english/staff/christ/onderwijs-teaching-material