Quantifying high-dimensional spatial entanglement with a single-photon-sensitive time-stamping camera

TL;DR

This paper demonstrates a method to quantify high-dimensional spatial entanglement using a single-photon-sensitive camera, enabling assumptions-free certification crucial for quantum information applications.

Contribution

It introduces a novel approach to measure high-dimensional entanglement without background subtraction or assumptions, advancing quantum certification techniques.

Findings

Position-momentum EPR correlations observed

Entanglement of formation exceeds 2.8

Dimensionality of entanglement is higher than 14

Abstract

High-dimensional entanglement is a promising resource for quantum technologies. Being able to certify it for any quantum state is essential. However, to date, experimental entanglement certification methods are imperfect and leave some loopholes open. Using a single-photon sensitive time-stamping camera, we quantify high-dimensional spatial entanglement by collecting all output modes and without background subtraction, two critical steps on the route towards assumptions-free entanglement certification. We show position-momentum Einstein-Podolsky-Rosen (EPR) correlations and quantify the entanglement of formation of our source to be larger than 2.8 along both transverse spatial axes, indicating a dimension higher than 14. Our work overcomes important challenges in photonic entanglement quantification and paves the way towards the development of practical quantum information processing protocols based on high-dimensional entanglement.