Fluctuations and Irreversibility: Historical and Modern Perspectives

TL;DR

This paper reviews the development of fluctuation theory and its connection to irreversibility, emphasizing recent advances in quantum fluctuation theorems and their implications for quantum thermodynamics and technology.

Contribution

It links quantum fluctuation theorems with linear response theory, providing new insights into quantum fluctuations and irreversibility near equilibrium.

Findings

Classical fluctuation theorems are well established.

Quantum fluctuation theorems are an active research area.

Dissipated work reveals non-classical effects in quantum thermodynamics.

Abstract

This article traces the development of fluctuation theory and its deep connection to irreversibility, from equilibrium to near-equilibrium, and finally to far-from-equilibrium systems. Classical fluctuation theorems, which capture the statistical behaviour of thermodynamic systems far from equilibrium, are now well established. Their quantum counterparts, however, remain an active area of research. In this review, we highlight recent advances by linking quantum fluctuation theorems with linear response theory, offering new insights into the nature of quantum fluctuations and irreversibility in the near-equilibrium regime. Particular emphasis is placed on dissipated work in quantum systems as a pathway to observing non-classical effects in quantum thermodynamics. Understanding quantum fluctuations is not only essential for clarifying the foundations of irreversibility but also crucial for the development of novel quantum technologies, including quantum computers, sensors, and metrological devices.