Fluctuation relations without microreversibility in nonlinear transport

TL;DR

This paper derives new fluctuation relations for nonlinear transport systems under magnetic fields, extending the understanding of current correlations beyond microreversibility assumptions, with applications demonstrated in an electrical interferometer.

Contribution

The paper introduces fluctuation relations applicable to nonlinear transport with magnetic fields, without relying on microreversibility, expanding theoretical frameworks.

Findings

Derived fluctuation relations relating current correlations and response coefficients.

Validated the theoretical results using an electrical Mach-Zehnder interferometer example.

Showed deviations from microreversibility in nonlinear transport phenomena.

Abstract

In linear transport, the fluctuation-dissipation theorem relates equilibrium current correlations to the linear conductance coefficient. For nonlinear transport, there exist fluctuation relations that rely on Onsager's principle of microscopic reversibility away from equilibrium. However, both theory and experiments have shown deviations from microreversibility in the form of magnetic field asymmetric current-voltage relations. We present novel fluctuation relations for nonlinear transport in the presence of magnetic fields that relate current correlation functions at any order at equilibrium to response coefficients of current cumulants of lower order. We illustrate our results with the example of an electrical Mach-Zehnder interferometer.