Noise-induced backscattering in a quantum-spin-Hall edge

TL;DR

This paper investigates how electromagnetic noise can cause inelastic backscattering in quantum-spin-Hall edges, leading to conductance suppression at finite temperatures, and proposes an experimental test for this mechanism.

Contribution

It introduces a novel noise-induced backscattering mechanism in quantum-spin-Hall edges and quantifies its effects on conductance corrections.

Findings

Electromagnetic noise can cause inelastic backscattering without electron-electron interactions.

Quantitative estimates of noise-induced conductance corrections in different regimes.

Proposed experimental setup to verify noise-induced backscattering effects.

Abstract

Time-reversal symmetry suppresses electron backscattering in a quantum-spin-Hall edge, yielding quantized conductance at zero temperature. Understanding the dominant corrections in finite-temperature experiments remains an unsettled issue. We study a novel mechanism for conductance suppression: backscattering caused by incoherent electromagnetic noise. Specifically, we show that an electric potential fluctuating randomly in time can backscatter electrons inelastically without constraints faced by electron-electron interactions. We quantify noise-induced corrections to the dc conductance in various regimes and propose an experiment to test this scenario.