Swapping Intra-photon entanglement to Inter-photon entanglement using linear optical devices

TL;DR

This paper introduces a linear optical protocol for converting intra-photon entanglement into inter-photon entanglement and demonstrates a symmetric quantum state transfer method without Bell-basis discrimination.

Contribution

It presents a novel linear optical scheme for entanglement swapping and quantum state transfer that avoids Bell-basis discrimination, using only standard optical components.

Findings

Successful proposal for intra- to inter-photon entanglement swapping

Implementation of a symmetric quantum state transfer protocol

Elimination of Bell-basis discrimination in the protocols

Abstract

We propose a curious protocol for swapping the intra-photon entanglement between path and polarization degrees of freedom of a single photon to inter-photon entanglement between two spatially separated photons which have never interacted. This is accomplished by using an experimental setup consisting of three suitable Mach-Zehnder interferometers along with number of beam splitters, polarization rotators and detectors. Using the same setup, we have also demonstrated an interesting quantum state transfer protocol, symmetric between Alice and Bob. Importantly, the Bell-basis discrimination is not required in both the swapping and state transfer protocols. Our proposal can be implemented using linear optical devices.