Positive Cross Correlations in a Normal-Conducting Fermionic Beam Splitter

TL;DR

This paper explores how cross-correlations in a fermionic electron beam splitter can be positive, negative, or zero, depending on scattering mechanisms, challenging the typical expectation of fermionic antibunching.

Contribution

It demonstrates that cross-correlation signs are influenced by edge-state interactions, not just fermionic statistics, providing new insights into quantum transport in fermionic systems.

Findings

Cross-correlations can be positive, negative, or zero.

Sign reversal is due to edge-state interactions.

Fermionic statistics do not solely determine correlation signs.

Abstract

We investigate a beam splitter experiment implemented in a normal conducting fermionic electron gas in the quantum Hall regime. The cross-correlations between the current fluctuations in the two exit leads of the three terminal device are found to be negative, zero or even positive depending on the scattering mechanism within the device. Reversal of the cross-correlations sign occurs due to interaction between different edge-states and does not reflect the statistics of the fermionic particles which `antibunch'.