Quantum Fluctuation Relations for Ensembles of Wave Functions

TL;DR

This paper introduces new quantum fluctuation relations based on ensembles of wave functions instead of density matrices, avoiding quantum collapse and redefining work as the change in Hamiltonian expectation.

Contribution

It proposes a novel framework for quantum fluctuation relations using wave function ensembles, differing from traditional density matrix approaches.

Findings

Derivation of new fluctuation relations without quantum collapse

Work defined as change in expectation value of Hamiltonian

Framework applicable to Schrödinger's wave function ensembles

Abstract

New quantum fluctuation relations are presented. In contrast with the the standard approach, where the initial state of the driven system is described by the (micro)canonical density matrix, here we assume that it is described by a (micro)canonical distribution of wave functions, as originally proposed by Schr\"odinger. While the standard fluctuation relations are based on von Neumann measurement postulate, these new fluctuation relations do not involve any quantum collapse, but involve instead a notion of work as the change in expectation of the Hamiltonian.