Abstract

Systems in contact with multiple reservoirs fall in nonequilibrium states characterized by sustained currents of energy and matter. While in small systems thermal fluctuations are accounted for by Master (or Fokker-Planck) equations, in infinite-size systems the dynamics is described by deterministic rate equations which may display, inter alia, multistability and limit cycles. At large but finite sizes, nonequilibrium conditions induce metastability, namely, small fluctuations within macroscopic attractors and rare random transitions between them. This is the regime of interest for many natural and man-made systems, ranging from (bio)chemical reaction networks to electronic circuits. Using concepts of large deviations theory, I will explain such nonequilibrium emergent behavior from the microscopic stochastic dynamics and describe how (stochastic) thermodynamics can be consistently formulated through all levels of description.