Universal dephasing in a chiral 1D interacting fermion system

TL;DR

This paper investigates how interactions cause dephasing in a one-dimensional chiral fermion system, revealing a universal power-law decay of coherence at high energies and zero temperature, with implications for quantum interferometry.

Contribution

It introduces a semiclassical approach to calculate dephasing in chiral 1D fermions, demonstrating a universal decay exponent independent of interaction strength.

Findings

Power-law decay of coherence with exponent 1 at T=0

Universal dephasing behavior regardless of interaction strength

Derived dephasing rate and fluctuation spectrum at finite temperature

Abstract

We consider dephasing by interactions in a one-dimensional chiral fermion system (e.g. a Quantum Hall edge state). For finite-range interactions, we calculate the spatial decay of the Green's function at fixed energy, which sets the contrast in a Mach-Zehnder interferometer. Using a physically transparent semiclassical ansatz, we find a power-law decay of the coherence at high energies and zero temperature (T=0), with a universal asymptotic exponent of 1, independent of the interaction strength. We obtain the dephasing rate at T>0 and the fluctuation spectrum acting on an electron.