Many-Particle Interferometry and Entanglement by Path Identity

TL;DR

This paper presents a novel many-particle interferometry scheme using path identity to generate and manipulate entangled states without direct interaction, linking interference patterns to entanglement properties.

Contribution

It introduces a general scheme for creating and controlling many-particle entangled states via path identity, enabling manipulation without direct particle interaction.

Findings

Generation of various entangled states, including Bell and GHZ states.

Entanglement and interference visibility are interconnected and controllable.

The scheme allows switching between different entangled states without particle interaction.

Abstract

We introduce a general scheme of many-particle interferometry in which two identical sources are used and "which-way information" is eliminated by making the paths of one or more particles identical (path identity). The scheme allows us to generate many-particle entangled states. We provide general forms of these states and show that they can be expressed as superpositions of various Dicke states. We illustrate cases in which the scheme produces maximally entangled two-qubit states (Bell states) and maximally three-tangled states (three-particle Greenberger-Horne-Zeilinger-class states). A striking feature of the scheme is that the entangled states can be manipulated without interacting with the entangled particles; for example, it is possible to switch between two distinct Bell states. Furthermore, each entangled state corresponds to a set of many-particle interference patterns. The visibility of these patterns and the amount of entanglement in a quantum state are connected to each other. The scheme also allows us to change the visibility and the amount of entanglement without interacting with the entangled particles and, therefore, has the potential to play an important role in quantum information science.