Nanoscale sensing of spatial correlations in nonequilibrium current noise

TL;DR

This paper develops a framework to analyze spatial correlations in nonequilibrium current noise using nitrogen-vacancy centers, revealing insights into electron distributions and excitations in 2D metals.

Contribution

It introduces a novel theoretical approach for computing spatiotemporal correlations of nonequilibrium current noise in the Boltzmann regime, applied to 2D metals.

Findings

Spatial noise structure reveals nonequilibrium electron distributions

Framework estimates experimental visibility of noise signatures

Provides insights into excitation lifetimes in transport

Abstract

Nitrogen-vacancy centers are spatially resolved probes of current noise. So far, current noise sensing with NV centers has primarily been used as a way to probe equilibrium transport coefficients. We develop a framework for computing the spatiotemporal correlations of nonequilibrium current noise in the Boltzmann regime, and apply it to two-dimensional metals in current-biased steady states. We argue that the spatial structure of the noise reveals the nonequilibrium nature of the electron distribution function, and more generally reveals the nature and lifetimes of the excitations responsible for transport. We estimate the visibility of these signatures in near-term experiments.