Nonequilibrium thermodynamics at the microscale: Work relations and the second law

TL;DR

This paper reviews recent developments in nonequilibrium thermodynamics at the microscale, focusing on work relations and the second law, highlighting how fluctuations influence thermodynamic behavior far from equilibrium.

Contribution

It discusses the fundamental fluctuation relations that extend the second law to microscopic systems far from equilibrium.

Findings

Fluctuation relations hold even far from equilibrium.

These relations provide insights into irreversibility at the microscale.

The second law is generalized through statistical fluctuation theorems.

Abstract

For macroscopic systems, the second law of thermodynamics establishes an inequality between the amount of work performed on a system in contact with a thermal reservoir, and the change in its free energy. For microscopic systems, this result must be considered statistically, as fluctuations around average behavior become substantial. In recent years it has become recognized that these fluctuations satisfy a number of strong and unexpected relations, which remain valid even when the system is driven far from equilibrium. We discuss these relations, and consider what they reveal about the second law of thermodynamics and the nature of irreversibility at the microscale.