Experimental Entanglement and Nonlocality of a Two-Photon Six-Qubit Cluster State

TL;DR

This paper reports the creation of a six-qubit linear cluster state using two photons entangled in multiple degrees of freedom, demonstrating advanced entanglement properties and Bell inequality violations.

Contribution

It introduces a method to generate a six-qubit cluster state from hyperentangled photons, showcasing genuine entanglement and robustness against qubit loss.

Findings

Demonstrated genuine six-qubit entanglement

Showed persistency of entanglement after qubit loss

Achieved higher Bell inequality violation than previous experiments

Abstract

We create a six-qubit linear cluster state by transforming a two-photon hyperentangled state in which three qubits are encoded in each particle, one in the polarization and two in the linear momentum degrees of freedom. For this state, we demonstrate genuine six-qubit entanglement, persistency of entanglement against the loss of qubits, and higher violation than in previous experiments on Bell inequalities of the Mermin type.