title: Postselection-Loophole-Free Bell Test Over an Installed Optical Fiber Network.
abstract: Device-independent quantum communication will require a loophole-free violation of Bell inequalities. In typical scenarios where line of sight between the communicating parties is not available, it is convenient to use energy-time entangled photons due to intrinsic robustness while propagating over optical fibers. Here we show an energy-time Clauser-Horne-Shimony-Holt Bell inequality violation with two parties separated by 3.7 km over the deployed optical fiber network belonging to the University of Concepción in Chile. Remarkably, this is the first Bell violation with spatially separated parties that is free of the postselection loophole, which affected all previous in-field long-distance energy-time experiments. Our work takes a further step towards a fiber-based loophole-free Bell test, which is highly desired for secure quantum communication due to the widespread existing telecommunication infrastructure.
authors.affiliation: Departamento de Física, Universidad de Concepción, 160-C Concepción, Chile.|Center for Optics and Photonics, Universidad de Concepción, Casilla 4016, Concepción, Chile.|MSI-Nucleus for Advanced Optics, Universidad de Concepción, 160-C Concepción, Chile.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Carvacho
authors.affiliation: Center for Optics and Photonics, Universidad de Concepción, Casilla 4016, Concepción, Chile.|MSI-Nucleus for Advanced Optics, Universidad de Concepción, 160-C Concepción, Chile.|Departamento de Ingeniería Eléctrica, Universidad de Concepción,160-C Concepción, Chile.
authors.forename: Jaime
authors.initials: J
authors.lastname: Cariñe
authors.affiliation: Center for Optics and Photonics, Universidad de Concepción, Casilla 4016, Concepción, Chile.|MSI-Nucleus for Advanced Optics, Universidad de Concepción, 160-C Concepción, Chile.|Departamento de Ingeniería Eléctrica, Universidad de Concepción,160-C Concepción, Chile.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Saavedra
authors.affiliation: Departamento de Física, Universidad de Concepción, 160-C Concepción, Chile.|Center for Optics and Photonics, Universidad de Concepción, Casilla 4016, Concepción, Chile.|MSI-Nucleus for Advanced Optics, Universidad de Concepción, 160-C Concepción, Chile.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Cuevas
authors.affiliation: Departamento de Física, Universidad de Concepción, 160-C Concepción, Chile.|Center for Optics and Photonics, Universidad de Concepción, Casilla 4016, Concepción, Chile.|MSI-Nucleus for Advanced Optics, Universidad de Concepción, 160-C Concepción, Chile.
authors.forename: Jorge
authors.initials: J
authors.lastname: Fuenzalida
authors.affiliation: Departamento de Física, Universidad de Concepción, 160-C Concepción, Chile.|Center for Optics and Photonics, Universidad de Concepción, Casilla 4016, Concepción, Chile.|MSI-Nucleus for Advanced Optics, Universidad de Concepción, 160-C Concepción, Chile.
authors.forename: Felipe
authors.initials: F
authors.lastname: Toledo
authors.affiliation: Center for Optics and Photonics, Universidad de Concepción, Casilla 4016, Concepción, Chile.|Departamento de Ingeniería Eléctrica, Universidad de Concepción,160-C Concepción, Chile.
authors.forename: Miguel
authors.initials: M
authors.lastname: Figueroa
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: Institutionen för Systemteknik, Linköpings Universitet, 581 83 Linköping, Sweden.
authors.forename: Jan-Åke
authors.initials: JÅ
authors.lastname: Larsson
authors.affiliation: Dipartimento de Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, Roma I-00185, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Mataloni
authors.affiliation: Departamento de Física, Universidad de Concepción, 160-C Concepción, Chile.|Center for Optics and Photonics, Universidad de Concepción, Casilla 4016, Concepción, Chile.|MSI-Nucleus for Advanced Optics, Universidad de Concepción, 160-C Concepción, Chile.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Lima
authors.affiliation: Center for Optics and Photonics, Universidad de Concepción, Casilla 4016, Concepción, Chile.|MSI-Nucleus for Advanced Optics, Universidad de Concepción, 160-C Concepción, Chile.|Departamento de Ingeniería Eléctrica, Universidad de Concepción,160-C Concepción, Chile.
authors.forename: Guilherme B
authors.initials: GB
authors.lastname: Xavier