Energetic fluctuations in an open quantum process

TL;DR

This paper derives a general framework for quantifying energetic and entropic changes in open quantum systems, applicable to complex dynamics without restrictions on the environment or ancilla.

Contribution

It extends fluctuation relations and develops a non-equilibrium Helmholtz equation for open quantum systems, independent of ancilla properties.

Findings

Provides a universal expression for energetic changes based on the system state and evolution map.

No assumptions on ancilla nature or dimension are required.

Applicable to complex quantum systems with open dynamics.

Abstract

Relations similar to work and exchange fluctuations have been recently derived for open systems dynamically evolving in the presence of an ancilla. Extending these relations and constructing a non-equilibrium Helmholtz equation we derive a general expression for the energetic and entropic changes of an open quantum system undergoing a nontrivial evolution. The expressions depend only on the state of the system and the dynamical map generating the evolution. Furthermore our formalism makes no assumption on either the nature or dimension of the ancilla. Our results are expected to find application in understanding the energetics of complex quantum systems undergoing open dynamics.