Mach-Zehnder interferometry with periodic voltage pulses

TL;DR

This paper studies a Mach-Zehnder interferometer driven by time-dependent voltages, analyzing how different pulse shapes and charges affect interference visibility and noise, revealing universal behaviors and temperature effects.

Contribution

It introduces a detailed analysis of Lorentzian voltage pulses in a Mach-Zehnder interferometer, highlighting universal charge-dependent phenomena and temperature influences in time-dependent quantum transport.

Findings

Distinct behavior of current with multiple charge pulses

Universal effects for fractional charge pulses at specific path differences

Unique temperature effects on current and noise

Abstract

We investigate a Mach-Zehnder interferometer driven by a time-dependent voltage. Motivated by recent experiments, we focus on a train of Lorentzian voltage pulses which we compare to a sinusoidal and a constant voltage. We discuss the visibilities of Aharonov-Bohm oscillations in the current and in the noise. For the current, we find a strikingly different behavior in the driven as compared to the static case for voltage pulses containing multiple charges. For pulses containing fractional charges, we find a universality at path-length differences equal to multiples of the spacing between the voltage pulses. These observations can be explained by the electronic energy distribution of the driven contact. In the noise oscillations, we find additional features which are characteristic to time-dependent transport. Finite electronic temperatures are found to have a qualitatively different influence on the current and the noise.