Path Integral Formalism for Quantum Open Systems

TL;DR

This paper develops a comprehensive path integral formalism for quantum open systems, covering bosons and fermions, with applications to various contours and generating functionals for environment-system analysis.

Contribution

It introduces a detailed derivation of the path integral approach for quantum open systems using coherent states, including multiple contour formalisms and generating functionals.

Findings

Derivation of path integral formalism for boson and fermion systems

Application of formalism to imaginary-time, Keldysh, and Kadanoff contours

Development of generating functional techniques for environment information retrieval

Abstract

This article provides a detailed derivation of the path integral formalism for both boson and fermion quantum open systems using coherent states. The formalism on the imaginary-time axis, Keldysh contour, and Kadanoff contour are given. The corresponding generating functional technique, which can be used to retrieve the environment information from the system correlation function, is also discussed.