Hyperentanglement witness

TL;DR

This paper introduces a new criterion for detecting hyperentanglement using entanglement witnesses, including a novel witness that enhances noise resistance through additional local measurements.

Contribution

It presents a new entanglement detection criterion for hyperentangled states and a novel witness that improves noise robustness with more local measurements.

Findings

Existing graph state witnesses can be adapted for hyperentanglement detection.

The new witness $W_3$ increases noise resistance.

Measurement efficiency is achieved with only two local settings.

Abstract

A new criterium to detect the entanglement present in a {\it hyperentangled state}, based on the evaluation of an entanglement witness, is presented. We show how some witnesses recently introduced for graph states, measured by only two local settings, can be used in this case. We also define a new witness $W_3$ that improves the resistance to noise by increasing the number of local measurements.