Decoherence in a double-slit quantum eraser

TL;DR

This paper demonstrates an experimental double-slit quantum eraser with controlled decoherence, showing the transition from wave-like to particle-like behavior of photons as decoherence increases.

Contribution

It introduces a novel experimental setup combining a birefringent double-slit and a Mach-Zehnder interferometer to control and study decoherence effects in a quantum eraser.

Findings

Decoherence causes a clear transition from wave to particle behavior.

The setup effectively models controlled decoherence in quantum systems.

Results align with theoretical predictions of decoherence effects.

Abstract

We study and experimentally implement a double-slit quantum eraser in the presence of a controlled decoherence mechanism. A two-photon state, produced in a spontaneous parametric down conversion process, is prepared in a maximally entangled polarization state. A birefringent double-slit is illuminated by one of the down-converted photons, and it acts as a single-photon two-qubits controlled not gate that couples the polarization with the transversal momentum of these photons. The other photon, that acts as a which-path marker, is sent through a Mach-Zehnder-like interferometer. When the interferometer is partially unbalanced, it behaves as a controlled source of decoherence for polarization states of down-converted photons. We show the transition from wave-like to particle-like behavior of the signal photons crossing the double-slit as a function of the decoherence parameter, which depends on the length path difference at the interferometer.