Over forty years of research towards the understanding of Quantum Brownian Motion -- the contributions of A. O. Caldeira

TL;DR

This paper reviews Amir O. Caldeira's extensive contributions to quantum Brownian motion, highlighting his models, effects on tunneling, and influence on quantum decoherence and thermodynamics over four decades.

Contribution

It summarizes Caldeira's novel approaches beyond the Caldeira-Leggett model and his impact on modern quantum theory fields.

Findings

Caldeira's work elucidated the role of dissipation in quantum tunneling.

He developed alternative approaches to quantum Brownian motion beyond the Caldeira-Leggett model.

His contributions significantly influenced quantum decoherence and thermodynamics theories.

Abstract

This article presents a brief account of Amir O. Caldeira's contributions to the theory of quantum Brownian motion. Motivated by its importance, we outline the description of Brownian motion in the quantum regime following Caldeira's first works. In this context, we particularly highlight the effect of dissipation on the tunneling rate out of a metastable state. We then journey along the alternative ways to approach quantum Brownian motion developed by Caldeira during his career, which go beyond the so-called Caldeira-Leggett model. We conclude by summarizing some of Caldeira's contributions to contemporary fields such as the theory of quantum decoherence and quantum thermodynamics, that were strongly inspired by his eponymous approach to quantum Brownian motion.