title: Approaching Tsirelson's Bound in a Photon Pair Experiment.
abstract: We present an experimental test of the Clauser-Horne-Shimony-Holt Bell inequality on photon pairs in a maximally entangled state of polarization in which a value S=2.82759±0.00051 is observed. This value comes close to the Tsirelson bound of |S|≤2sqrt[2], with S-2sqrt[2]=0.00084±0.00051. It also violates the bound |S|≤2.82537 introduced by Grinbaum by 4.3 standard deviations. This violation allows us to exclude that quantum mechanics is only an effective description of a more fundamental theory.
authors.affiliation: Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore.
authors.forename: Hou Shun
authors.initials: HS
authors.lastname: Poh
authors.affiliation: Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore.
authors.forename: Siddarth K
authors.initials: SK
authors.lastname: Joshi
authors.affiliation: Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Cerè
authors.affiliation: Departamento de Física Aplicada II, Universidad de Sevilla, E-41012 Sevilla, Spain.
authors.forename: Adán
authors.initials: A
authors.lastname: Cabello
authors.affiliation: Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore.|Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.
authors.forename: Christian
authors.initials: C
authors.lastname: Kurtsiefer