Fluctuation-dissipation theorem for chiral systems in non-equilibrium steady states

TL;DR

This paper derives a generalized fluctuation-dissipation relation for non-equilibrium chiral systems, linking current noise to nonlinear response, aiding the detection of upstream modes in quantum Hall edges.

Contribution

It establishes a universal fluctuation-dissipation relation for non-equilibrium chiral systems, extending equilibrium concepts to nonlinear regimes.

Findings

Derived a fluctuation-dissipation relation for non-equilibrium chiral systems.

Applicable to general chiral systems and quantum Hall edge modes.

Provides a method to detect upstream modes via noise measurements.

Abstract

We consider a three-terminal system with a chiral edge channel connecting the source and drain terminals. Charge can tunnel between the chiral edge and a third terminal. The third terminal is maintained at a different temperature and voltage than the source and drain. We prove a general relation for the current noises detected in the drain and third terminal. It has the same structure as an equilibrium fluctuation-dissipation relation with the nonlinear response in place of the linear conductance. The result applies to a general chiral system and can be useful for detecting "upstream" modes on quantum Hall edges.