Generating Greenberger-Horne-Zeilinger states using multiport splitters

TL;DR

This paper demonstrates how symmetric multiport beam splitters can probabilistically generate N-photon GHZ states, introducing two new schemes for odd and even photon numbers and comparing them to existing methods.

Contribution

It introduces two novel schemes for generating GHZ states with symmetric multiport splitters for odd and even photon numbers, expanding quantum state engineering techniques.

Findings

Successful probabilistic generation of GHZ states using multiport splitters

Comparison shows advantages over standard post-selection methods

Schemes applicable to arbitrary photon numbers

Abstract

Symmetric multiport splitters are versatile tools in optical quantum information processing. They can be used for studying multiparticle scattering, studying distinguishability and mixedness, and also for the generation of multipartite entangled quantum states. Here, we show that N-photon N-mode Greenberger-Horne-Zeilinger (GHZ) states can be generated using symmetric multiport beam splitters. Varying the input states' internal degrees of freedom and post-selecting onto certain photon-number distributions allows the probabilistic generation of GHZ states with arbitrary photon numbers. We present two novel schemes, one for odd and one for even numbers of photons, to generate GHZ states using symmetric multiport splitters and compare them to a strategy utilizing a 2N-port network as well as the standard post-selection method.