Experimental measurement of nonlinear entanglement witness by hyper-entangling two-qubit states

TL;DR

This paper experimentally demonstrates that nonlinear entanglement witnesses can be effectively measured using hyper-entangled two-photon states in linear optics, enabling rapid entanglement detection on single copies.

Contribution

It introduces a practical method to measure nonlinear entanglement witnesses directly on hyper-entangled states, simplifying entanglement detection procedures.

Findings

Nonlinear entanglement witnesses can be measured on single hyper-entangled states.

Hyper-entanglement enables quick and practical entanglement detection.

Experimental validation using linear optics with two photons.

Abstract

We demonstrate that non-linear entanglement witnesses can be made particularly useful for entanglement detection in hyper-entangled or multilevel states. We test this idea experimentally on the platform of linear optics using a hyper-entangled state of two photons. Instead of several simultaneous copies of two-photon entangled states, one can directly measure the witness on single copy of a hyper-entangled state. Our results indicate that hyper-entanglement can be used for quick entanglement detection and it provides a practical testbed for experiments with non-linear entanglement witnesses.