A Brief Introduction to Observational Entropy

In the past several years, observational entropy has been developed as both a (time-dependent) quantum generalization of Boltzmann entropy, and as a rather general framework to encompass classical and quantum equilibrium and non-equilibrium coarse-grained entropy. In this paper we review the construction, interpretation, most important properties, and some applications of this framework. The treatment is self-contained and relatively pedagogical, aimed at a broad class of researchers.

Automated summary

Observational entropy has been developed as a quantum generalization of Boltzmann entropy and a general framework for classical and quantum equilibrium and non-equilibrium coarse-grained entropy. This paper reviews its construction, interpretation, important properties, and applications, aimed at a broad class of researchers in a self-contained and pedagogical manner.