All-Versus-Nothing Nonlocality Test of Quantum Mechanics by Two-Photon Hyperentanglement

Abstract

We report the experimental realization and the characterization of polarization and momentum hyperentangled two-photon states, generated by a new parametric source of correlated photon pairs. By adoption of these states an "all-versus-nothing" test of quantum mechanics was performed. The two-photon hyperentangled states are expected to find at an increasing rate a widespread application in state engineering and quantum information.

Multipath Entanglement of Two Photons

“…Polarization, time bin and spatial entanglement have been adopted to create qu-dits with d = 3 [6,16], d = 4 [17] and d = 8 [18]. At the same time, HE states have been realized by using in different ways polarization, longitudinal momentum and orbital angular momentum, besides time-bin entanglement [1,19,20,21,22].In this paper we present the first experimental realization of a quantum state of two photons entangled in many optical paths. It is based on the spontaneous parametric down conversion (SPDC) emission of a Type I phase-matched nonlinear (NL) crystal operating under the excitation of a continuous wave (cw) laser at wavelength (wl) λ p .…”

Experimental Realization of One-Way Quantum Computing with Two-Photon Four-Qubit Cluster States

“…Besides, the quality and fidelity of prepared cluster states are relatively low [6,7,8], which are difficult to be improved substantially. These disadvantages consequently impose great challenges of advancement even for few-qubit quantum computing.Fortunately, motivated by the progress that an important type of states termed hyper-entangled states have been experimentally generated [11,12,13,14], we have the possibility to produce a new type of cluster state (2-photon 4-qubit cluster state) with nearly perfect fidelity and high generation rate. The hyper-entangled states have been used to test "All-Versus-Nothing" (AVN) quantum nonlocality [11,12,15], and are shown to lead to an enhancing violation of local realism [16,17].…”

“…The hyper-entangled states have been used to test "All-Versus-Nothing" (AVN) quantum nonlocality [11,12,15], and are shown to lead to an enhancing violation of local realism [16,17]. The states also enable to perform complete deterministic Bell state analysis [18] as demonstrated in [14,19].…”

Bipartite Bell Inequalities for Hyperentangled States

“…entangled in several degrees of freedom [10]. Hyperentanglement has been demonstrated in recent experiments with two photons entangled in two degrees of freedom (polarization and path) [11], and in three degrees of freedom (polarization, path, and time-energy) [12]. Indeed, timebin entanglement would allow us to encapsulate a higher number of qubits [13].…”

“…Examples of bipartite EPR-BIs have been introduced [15,16,17] and experimentally tested [11] recently. The aim of this Letter is to explore the merits of these new equalities-based BIs when we move to higher dimensions.…”