Optimal verification of entanglement in a photonic cluster state experiment

Abstract

We report on the quantification of entanglement by means of entanglement measures on a four- and a six-qubit cluster state realized by using photons entangled both in polarization and linear momentum. This paper also addresses the question of the scaling of entanglement bounds from incomplete tomographic information on the density matrix under realistic experimental conditions. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.