title: Strong Loophole-Free Test of Local Realism.
abstract: We present a loophole-free violation of local realism using entangled photon pairs. We ensure that all relevant events in our Bell test are spacelike separated by placing the parties far enough apart and by using fast random number generators and high-speed polarization measurements. A high-quality polarization-entangled source of photons, combined with high-efficiency, low-noise, single-photon detectors, allows us to make measurements without requiring any fair-sampling assumptions. Using a hypothesis test, we compute p values as small as 5.9×10^{-9} for our Bell violation while maintaining the spacelike separation of our events. We estimate the degree to which a local realistic system could predict our measurement choices. Accounting for this predictability, our smallest adjusted p value is 2.3×10^{-7}. We therefore reject the hypothesis that local realism governs our experiment.
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
authors.forename: Lynden K
authors.initials: LK
authors.lastname: Shalm
authors.affiliation: Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada, N2L 3G1.
authors.forename: Evan
authors.initials: E
authors.lastname: Meyer-Scott
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Bradley G
authors.initials: BG
authors.lastname: Christensen
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Bierhorst
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.|National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Wayne
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Stevens
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Gerrits
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Glancy
authors.affiliation: Département de Physique et d'Astronomie, Université de Moncton, Moncton, New Brunswick E1A 3E9, Canada.
authors.forename: Deny R
authors.initials: DR
authors.lastname: Hamel
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Allman
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Coakley
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
authors.forename: Shellee D
authors.initials: SD
authors.lastname: Dyer
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
authors.forename: Carson
authors.initials: C
authors.lastname: Hodge
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
authors.forename: Adriana E
authors.initials: AE
authors.lastname: Lita
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
authors.forename: Varun B
authors.initials: VB
authors.lastname: Verma
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
authors.forename: Camilla
authors.initials: C
authors.lastname: Lambrocco
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Tortorici
authors.affiliation: National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA.|Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA.
authors.forename: Alan L
authors.initials: AL
authors.lastname: Migdall
authors.affiliation: Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada, N2L 3G1.
authors.forename: Yanbao
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Kumor
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, USA.
authors.forename: William H
authors.initials: WH
authors.lastname: Farr
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, USA.
authors.forename: Francesco
authors.initials: F
authors.lastname: Marsili
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, USA.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Shaw
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, USA.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Stern
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Abellán
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.
authors.forename: Waldimar
authors.initials: W
authors.lastname: Amaya
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.|ICREA-Institució Catalana de Recerca i Estudis Avançats, 08015 Barcelona, Spain.
authors.forename: Valerio
authors.initials: V
authors.lastname: Pruneri
authors.affiliation: Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada, N2L 3G1.|Quantum Information Science Program, Canadian Institute for Advanced Research, Toronto, Ontario, Canada.
authors.forename: Thomas
authors.initials: T
authors.lastname: Jennewein
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.|ICREA-Institució Catalana de Recerca i Estudis Avançats, 08015 Barcelona, Spain.
authors.forename: Morgan W
authors.initials: MW
authors.lastname: Mitchell
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Paul G
authors.initials: PG
authors.lastname: Kwiat
authors.affiliation: National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA.|Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA.
authors.forename: Joshua C
authors.initials: JC
authors.lastname: Bienfang
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Mirin
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
authors.forename: Emanuel
authors.initials: E
authors.lastname: Knill
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
authors.forename: Sae Woo
authors.initials: SW
authors.lastname: Nam