High-dimensional entanglement certification

TL;DR

This paper introduces an efficient, information-theoretic method for certifying high-dimensional entanglement in large quantum systems, demonstrated experimentally on photon pairs up to 32 dimensions.

Contribution

It presents a scalable entanglement certification protocol suitable for large systems, using only two local measurements, advancing beyond traditional Bell inequalities.

Findings

Successfully certified entanglement in 32-dimensional photon pairs.

The method scales efficiently with system size and can identify maximally entangled states.

Experimental validation confirms the protocol's practicality and effectiveness.

Abstract

Quantum entanglement is the ability of joint quantum systems to possess global properties (correlation among systems) even when subsystems have no definite individual property. Whilst the 2-dimensional (qubit) case is well-understood, currently, tools to characterise entanglement in high dimensions are limited. We experimentally demonstrate a new procedure for entanglement certification that is suitable for large systems, based entirely on information-theoretics. It scales more efficiently than Bell's inequality, and entanglement witness. The method we developed works for arbitrarily large system dimension $d$ and employs only two local measurements of complementary properties. This procedure can also certify whether the system is maximally entangled. We illustrate the protocol for families of bipartite states of qudits with dimension up to $32$ composed of polarisation-entangled photon pairs.