Entanglement, Dephasing, and Phase Recovery via Cross-Correlation Measurements of Electrons

TL;DR

This paper demonstrates how cross-correlation measurements can recover interference in a two-path electron interferometer after dephasing, revealing entanglement and phase information lost due to which-path detection.

Contribution

It introduces a method to recover quantum interference after dephasing using cross-correlation measurements, highlighting entanglement effects in electron interferometry.

Findings

Full suppression of interference with which-path detection

Interference can be recovered via cross-correlation measurements

Dephasing involves entanglement of approximately single electron pairs

Abstract

Determination of the path taken by a quantum particle leads to a suppression of interference and to a classical behavior. We employ here a quantum 'which path' detector to perform accurate path determination in a two-path-electron-interferometer; leading to full suppression of the interference. Following the dephasing process we recover the interference by measuring the cross-correlation between the interferometer and detector currents. Under our measurement conditions every interfering electron is dephased by approximately a single electron in the detector - leading to mutual entanglement of approximately single pairs of electrons.