Fermionic Mach-Zehnder interferometer subject to a quantum bath

TL;DR

This paper investigates how a quantum environment affects fermionic Mach-Zehnder interferometers, analyzing inelastic scattering, decoherence, and conductance fluctuations, with detailed calculations of interference loss and shot noise.

Contribution

It provides a comprehensive analysis of dephasing effects in fermionic interferometers due to a quantum bath, including the dependence on experimental parameters and comparison with simpler models.

Findings

Interference contrast decreases due to inelastic scattering and decoherence.

Shot noise correction depends on voltage, temperature, and bath spectrum.

Correlations between phase fluctuations and output current are significant.

Abstract

We study fermions in a Mach-Zehnder interferometer, subject to a quantum-mechanical environment leading to inelastic scattering, decoherence, renormalization effects, and time-dependent conductance fluctuations. Both the loss of interference contrast as well as the shot noise are calculated, using equations of motion and leading order perturbation theory. The full dependence of the shot-noise correction on setup parameters, voltage, temperature and the bath spectrum is presented. We find an interesting contribution due to correlations between the fluctuating renormalized phase shift and the output current, discuss the limiting behaviours at low and high voltages, and compare with simpler models of dephasing.