Visibility recovery by strong interaction in an electronic Mach-Zehnder interferometer

TL;DR

This paper investigates how strong Coulomb interactions in an electronic Mach-Zehnder interferometer can restore the original electron packet shape and enhance interference visibility, revealing non-trivial effects of interaction strength.

Contribution

It demonstrates that increasing interaction strength initially distorts but ultimately recovers the Lorentzian packet shape and maximizes interference visibility, a counterintuitive phenomenon not previously shown.

Findings

Electron density profile becomes less distorted at strong interactions.

Interference visibility recovers and maximizes at strong interactions.

Counterintuitive relationship between interaction strength and visibility.

Abstract

We study the evolution of a single-electron packet of Lorentzian shape along an edge of the integer quantum Hall regime or in a Mach-Zehnder interferometer, considering a capacitive Coulomb interaction and using a bosonization approach. When the packet propagates along a chiral quantum Hall edge, we find that its electron density profile becomes more distorted from Lorentzian due to the generation of electron-hole excitations, as the interaction strength increases yet stays in a weak interaction regime. However, as the interaction strength becomes larger and enters a strong interaction regime, the distortion becomes weaker and eventually the Lorentzian packet shape is recovered. The recovery of the packet shape leads to an interesting feature of the interference visibility of the symmetric Mach-Zehnder interferometer whose two arms have the same interaction strength. As the interaction strength increases, the visibility decreases from the maximum value in the weak interaction regime, and then increases to the maximum value in the strong interaction regime. We argue that this counterintuitive result also occurs under other types of interactions.