Influence of channel mixing in fermionic Hong-Ou-Mandel experiments

TL;DR

This paper investigates how channel mixing due to tunneling between copropagating edge channels in a quantum Hall interferometer can reduce the visibility of the Pauli dip, challenging previous assumptions that interactions are the main cause.

Contribution

It demonstrates that channel mixing, not electron-electron interactions, can cause reduced Hong-Ou-Mandel interference visibility at filling factor ν=2.

Findings

Channel mixing can reduce Pauli dip visibility.

Electron-electron interactions do not account for reduced visibility.

Tunneling between edge channels explains experimental observations.

Abstract

We consider an electronic Hong-Ou-Mandel interferometer in the integer quantum Hall regime, where the colliding electronic states are generated by applying voltage pulses (creating for instance Levitons) to ohmic contacts. The aim of this work is to investigate possible mechanisms leading to a reduced visibility of the Pauli dip, i.e., the noise suppression expected for synchronized sources. It is known that electron-electron interactions cannot account for this effect and always lead to a full suppression of the Hong-Ou-Mandel noise. Focusing on the case of filling factor $\nu=2$, we show instead that a reduced visibility of the Pauli dip can result from mixing of the copropagating edge channels, arising from tunneling events between them.