Experimental high-dimensional two-photon entanglement and violations of generalised Bell inequalities

TL;DR

This paper experimentally demonstrates high-dimensional entangled photon states up to 12 dimensions using orbital angular momentum, showing violations of generalized Bell inequalities and confirming genuine 11-dimensional entanglement, advancing quantum information capabilities.

Contribution

The study provides the first experimental violation of generalized Bell inequalities in high-dimensional systems up to d=12, confirming genuine 11-dimensional entanglement using OAM photons.

Findings

Violations of Bell inequalities up to d=12 dimensions.

Confirmation of genuine 11-dimensional entanglement.

Use of OAM photons manipulated with holograms.

Abstract

Quantum entanglement plays a vital role in many quantum information and communication tasks. Entangled states of higher dimensional systems are of great interest due to the extended possibilities they provide. For example, they allow the realisation of new types of quantum information schemes that can offer higher information-density coding and greater resilience to errors than can be achieved with entangled two-dimensional systems. Closing the detection loophole in Bell test experiments is also more experimentally feasible when higher dimensional entangled systems are used. We have measured previously untested correlations between two photons to experimentally demonstrate high-dimensional entangled states. We obtain violations of Bell-type inequalities generalised to d-dimensional systems with up to d = 12. Furthermore, the violations are strong enough to indicate genuine 11-dimensional entanglement. Our experiments use photons entangled in orbital angular momentum (OAM), generated through spontaneous parametric down-conversion (SPDC), and manipulated using computer controlled holograms.