title: Experimental violation of Bell inequalities for multi-dimensional systems.
abstract: Quantum correlations between spatially separated parts of a d-dimensional bipartite system (d ≥ 2) have no classical analog. Such correlations, also called entanglements, are not only conceptually important, but also have a profound impact on information science. In theory the violation of Bell inequalities based on local realistic theories for d-dimensional systems provides evidence of quantum nonlocality. Experimental verification is required to confirm whether a quantum system of extremely large dimension can possess this feature, however it has never been performed for large dimension. Here, we report that Bell inequalities are experimentally violated for bipartite quantum systems of dimensionality d = 16 with the usual ensembles of polarization-entangled photon pairs. We also estimate that our entanglement source violates Bell inequalities for extremely high dimensionality of d > 4000. The designed scenario offers a possible new method to investigate the entanglement of multipartite systems of large dimensionality and their application in quantum information processing.
authors.affiliation: Department of Electrophysics, National Chiao-Tung University, Hsinchu City 300, Taiwan.
authors.forename: Hsin-Pin
authors.initials: HP
authors.lastname: Lo
authors.affiliation: Department of Engineering Science, National Cheng-Kung University, Tainan City 701, Taiwan.
authors.forename: Che-Ming
authors.initials: CM
authors.lastname: Li
authors.affiliation: Department of Electrophysics, National Chiao-Tung University, Hsinchu City 300, Taiwan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yabushita
authors.affiliation: Department of Physics and National Center for Theoretical Sciences, National Cheng-Kung University, Tainan City 701, Taiwan.
authors.forename: Yueh-Nan
authors.initials: YN
authors.lastname: Chen
authors.affiliation: Department of Electrophysics, National Chiao-Tung University, Hsinchu City 300, Taiwan.
authors.forename: Chih-Wei
authors.initials: CW
authors.lastname: Luo
authors.affiliation: Department of Electrophysics, National Chiao-Tung University, Hsinchu City 300, Taiwan.|Advanced Ultrafast Laser Research Center and Department of Engineering Science, University of Electro-Communications, Chofu, Tokyo 182-8585, Japan.|JST, CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 Japan.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Kobayashi