Heralding Higher-Dimensional Bell and Greenberger-Horne-Zeilinger States Using Multiport Splitters

TL;DR

This paper presents resource-efficient, high-success-probability schemes for heralding higher-dimensional entangled states, such as GHZ and Bell states, using multiphoton interference adaptable to various degrees of freedom.

Contribution

It introduces easily implementable schemes for heralding complex entangled states that are adaptable and require fewer resources than existing methods.

Findings

High success probabilities achieved

Schemes are adaptable to arbitrary degrees of freedom

Require fewer auxiliary photons

Abstract

One of the most important resources for quantum optical experiments and applications are on-demand highly entangled multiphoton quantum states. A promising way of generating them is heralding entanglement generation at a high rate from letting independent photons interfere. However, such schemes often work for a specific internal degree of freedom of the interfering photons only. Going to higher numbers of entangled photons, the success probabilities decrease while the number of necessary resources, e.g., auxiliary photons and optical elements, increases. To make probabilistic schemes feasible also for larger quantum states, it is therefore important to find resource-efficient generation schemes with high success probabilities. In this work, we introduce easily implementable schemes to herald qubit Greenberger-Horne-Zeilinger (GHZ) states, higher-dimensional Bell states and higher-dimensional three-party GHZ states. Our schemes solely rely on multiphoton interference, i.e., they can be adjusted to work for arbitrary degrees of freedom. Furthermore, they demonstrate high success probabilities and need comparably few auxiliary photons.