Entanglement preparation using symmetric multiports

TL;DR

This paper explores how symmetric multiport interferometers can generate and characterize entanglement, especially with single photons, providing conditions to identify and create various multi-photon entangled states.

Contribution

It derives a simple condition for entanglement types in single-photon input cases and extends these results to multi-photon state preparation using symmetric multiports.

Findings

Derived a condition characterizing entanglement types with single photons.

Showed how to determine multi-photon entangled states achievable with the interferometer.

Provided insights into entanglement generation using symmetric multiports.

Abstract

We investigate the entanglement produced by a multi-path interferometer that is composed of two symmetric multiports, with phase shifts applied to the output of the first multiport. Particular attention is paid to the case when we have a single photon entering the interferometer. For this situation we derive a simple condition that characterize the types of entanglement that one can generate. We then show how one can use the results from the single photon case to determine what kinds of multi-photon entangled states one can prepare using the interferometer.