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Gebhart V, Pezzè L, Smerzi A. Genuine Multipartite Nonlocality with Causal-Diagram Postselection. PHYSICAL REVIEW LETTERS 2021; 127:140401. [PMID: 34652187 DOI: 10.1103/physrevlett.127.140401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 09/02/2021] [Indexed: 06/13/2023]
Abstract
The generation and verification of genuine multipartite nonlocality (GMN) is of central interest for both fundamental research and quantum technological applications, such as quantum privacy. To demonstrate GMN in measurement data, the statistics are commonly postselected by neglecting undesired data. Until now, valid postselection strategies have been restricted to local postselection. A general postselection that is decided after communication between parties can mimic nonlocality, even though the complete data are local. Here, we establish conditions under which GMN is demonstrable even if observations are postselected collectively. Intriguingly, certain postselection strategies that require communication among several parties still offer a demonstration of GMN shared between all parties. The results are derived using the causal structure of the experiment and the no-signaling condition imposed by relativity. Finally, we apply our results to show that genuine three-partite nonlocality can be created with independent particle sources.
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Affiliation(s)
- Valentin Gebhart
- QSTAR, INO-CNR and LENS, Largo Enrico Fermi 2, 50125 Firenze, Italy
- Università degli Studi di Napoli "Federico II", Via Cinthia 21, 80126 Napoli, Italy
| | - Luca Pezzè
- QSTAR, INO-CNR and LENS, Largo Enrico Fermi 2, 50125 Firenze, Italy
| | - Augusto Smerzi
- QSTAR, INO-CNR and LENS, Largo Enrico Fermi 2, 50125 Firenze, Italy
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2
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Lum DJ, Mazurek MD, Mikhaylov A, Parzuchowski KM, Wilson RN, Jimenez R, Gerrits T, Stevens MJ, Cicerone MT, Camp CH. Witnessing the survival of time-energy entanglement through biological tissue and scattering media. BIOMEDICAL OPTICS EXPRESS 2021; 12:3658-3670. [PMID: 34221686 PMCID: PMC8221931 DOI: 10.1364/boe.423743] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 06/13/2023]
Abstract
We demonstrate the preservation of the time-energy entanglement of near-IR photons through thick biological media (≤1.55 mm) and tissue (≤ 235 μm) at room temperature. Using a Franson-type interferometer, we demonstrate interferometric contrast of over 0.9 in skim milk, 2% milk, and chicken tissue. This work supports the many proposed opportunities for nonclassical light in biological imaging and analyses from sub-shot noise measurements to entanglement-enhanced fluorescence imaging, clearly indicating that the entanglement characteristics of photons can be maintained even after propagation through thick, turbid biological samples.
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Affiliation(s)
- Daniel J. Lum
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Michael D. Mazurek
- Department of Physics, University of Colorado, Boulder CO 80309, USA
- National Institute of Standards and Technology, Boulder, CO 80305, USA
| | | | - Kristen M. Parzuchowski
- Department of Physics, University of Colorado, Boulder CO 80309, USA
- JILA, 440 UCB, University of Colorado, Boulder, CO 80309, USA
| | - Ryan N. Wilson
- Department of Physics, University of Colorado, Boulder CO 80309, USA
- JILA, 440 UCB, University of Colorado, Boulder, CO 80309, USA
| | - Ralph Jimenez
- JILA, 440 UCB, University of Colorado, Boulder, CO 80309, USA
- Department of Chemistry, 215 UCB, University of Colorado, Boulder, CO 80309, USA
| | - Thomas Gerrits
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Martin J. Stevens
- National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - Marcus T. Cicerone
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Charles H. Camp
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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3
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Anwar A, Perumangatt C, Steinlechner F, Jennewein T, Ling A. Entangled photon-pair sources based on three-wave mixing in bulk crystals. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:041101. [PMID: 34243479 DOI: 10.1063/5.0023103] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 03/01/2021] [Indexed: 06/13/2023]
Abstract
Entangled photon pairs are a critical resource in quantum communication protocols ranging from quantum key distribution to teleportation. The current workhorse technique for producing photon pairs is via spontaneous parametric down conversion (SPDC) in bulk nonlinear crystals. The increased prominence of quantum networks has led to a growing interest in deployable high performance entangled photon-pair sources. This manuscript provides a review of the state-of-the-art bulk-optics-based SPDC sources with continuous wave pump and discusses some of the main considerations when building for deployment.
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Affiliation(s)
- Ali Anwar
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, S117543 Singapore, Singapore
| | - Chithrabhanu Perumangatt
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, S117543 Singapore, Singapore
| | - Fabian Steinlechner
- Fraunhofer Institute for Applied Optics and Precision Engineering IOF, Albert-Einstein-Straße 7, 07745 Jena, Germany
| | - Thomas Jennewein
- Institute of Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Ave. W, Waterloo, Ontario N2L 3G1, Canada
| | - Alexander Ling
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, S117543 Singapore, Singapore
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4
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Vedovato F, Agnesi C, Tomasin M, Avesani M, Larsson JÅ, Vallone G, Villoresi P. Postselection-Loophole-Free Bell Violation with Genuine Time-Bin Entanglement. PHYSICAL REVIEW LETTERS 2018; 121:190401. [PMID: 30468593 DOI: 10.1103/physrevlett.121.190401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 09/11/2018] [Indexed: 06/09/2023]
Abstract
Entanglement is an invaluable resource for fundamental tests of physics and the implementation of quantum information protocols such as device-independent secure communications. In particular, time-bin entanglement is widely exploited to reach these purposes both in free space and optical fiber propagation, due to the robustness and simplicity of its implementation. However, all existing realizations of time-bin entanglement suffer from an intrinsic postselection loophole, which undermines their usefulness. Here, we report the first experimental violation of Bell's inequality with "genuine" time-bin entanglement, free of the postselection loophole. We introduced a novel function of the interferometers at the two measurement stations, that operate as fast synchronized optical switches. This scheme allowed us to obtain a postselection-loophole-free Bell violation of more than 9 standard deviations. Since our scheme is fully implementable using standard fiber-based components and is compatible with modern integrated photonics, our results pave the way for the distribution of genuine time-bin entanglement over long distances.
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Affiliation(s)
- Francesco Vedovato
- Dipartimento di Ingegneria dell'Informazione, Università di Padova, via Gradenigo 6B, 35131 Padova, Italy
- Centro di Ateneo di Studi e Attività Spaziali "G. Colombo", Università di Padova, via Venezia 15, 35131 Padova, Italy
| | - Costantino Agnesi
- Dipartimento di Ingegneria dell'Informazione, Università di Padova, via Gradenigo 6B, 35131 Padova, Italy
| | - Marco Tomasin
- Dipartimento di Ingegneria dell'Informazione, Università di Padova, via Gradenigo 6B, 35131 Padova, Italy
| | - Marco Avesani
- Dipartimento di Ingegneria dell'Informazione, Università di Padova, via Gradenigo 6B, 35131 Padova, Italy
| | - Jan-Åke Larsson
- Institutionen för systemteknik, Linköping Universitet, 581 83 Linköping, Sweden
| | - Giuseppe Vallone
- Dipartimento di Ingegneria dell'Informazione, Università di Padova, via Gradenigo 6B, 35131 Padova, Italy
- Istituto di Fotonica e Nanotecnologie, CNR, via Trasea 7, 35131 Padova, Italy
| | - Paolo Villoresi
- Dipartimento di Ingegneria dell'Informazione, Università di Padova, via Gradenigo 6B, 35131 Padova, Italy
- Istituto di Fotonica e Nanotecnologie, CNR, via Trasea 7, 35131 Padova, Italy
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5
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Baltanás JP, Frustaglia D. Entanglement discrimination in multi-rail electron-hole currents. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:485302. [PMID: 26569568 DOI: 10.1088/0953-8984/27/48/485302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We propose a quantum-Hall interferometer that integrates an electron-hole entangler with an analyzer working as an entanglement witness by implementing a multi-rail encoding. The witness has the ability to discriminate (and quantify) spatial-mode and occupancy entanglement. This represents a feasible alternative to limited approaches based on the violation of Bell-like inequalities.
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Affiliation(s)
- J P Baltanás
- Departamento de Física Aplicada II, Universidad de Sevilla, E-41012 Sevilla, Spain
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6
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Jogenfors J, Elhassan AM, Ahrens J, Bourennane M, Larsson JÅ. Hacking the Bell test using classical light in energy-time entanglement-based quantum key distribution. SCIENCE ADVANCES 2015; 1:e1500793. [PMID: 26824059 PMCID: PMC4730850 DOI: 10.1126/sciadv.1500793] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/29/2015] [Indexed: 06/05/2023]
Abstract
Photonic systems based on energy-time entanglement have been proposed to test local realism using the Bell inequality. A violation of this inequality normally also certifies security of device-independent quantum key distribution (QKD) so that an attacker cannot eavesdrop or control the system. We show how this security test can be circumvented in energy-time entangled systems when using standard avalanche photodetectors, allowing an attacker to compromise the system without leaving a trace. We reach Bell values up to 3.63 at 97.6% faked detector efficiency using tailored pulses of classical light, which exceeds even the quantum prediction. This is the first demonstration of a violation-faking source that gives both tunable violation and high faked detector efficiency. The implications are severe: the standard Clauser-Horne-Shimony-Holt inequality cannot be used to show device-independent security for energy-time entanglement setups based on Franson's configuration. However, device-independent security can be reestablished, and we conclude by listing a number of improved tests and experimental setups that would protect against all current and future attacks of this type.
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Affiliation(s)
- Jonathan Jogenfors
- Institutionen för Systemteknik, Linköpings Universitet, 581 83 Linköping, Sweden
| | | | - Johan Ahrens
- Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
| | | | - Jan-Åke Larsson
- Institutionen för Systemteknik, Linköpings Universitet, 581 83 Linköping, Sweden
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7
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Carvacho G, Cariñe J, Saavedra G, Cuevas Á, Fuenzalida J, Toledo F, Figueroa M, Cabello A, Larsson JÅ, Mataloni P, Lima G, Xavier GB. Postselection-Loophole-Free Bell Test Over an Installed Optical Fiber Network. PHYSICAL REVIEW LETTERS 2015; 115:030503. [PMID: 26230776 DOI: 10.1103/physrevlett.115.030503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Indexed: 06/04/2023]
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.
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Affiliation(s)
- Gonzalo Carvacho
- 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
| | - Jaime Cariñe
- 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
| | - Gabriel Saavedra
- 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
| | - Álvaro Cuevas
- 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
| | - Jorge Fuenzalida
- 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
| | - Felipe Toledo
- 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
| | - Miguel Figueroa
- Center for Optics and Photonics, Universidad de Concepción, Casilla 4016, Concepción, Chile
- Departamento de Ingeniería Eléctrica, Universidad de Concepción,160-C Concepción, Chile
| | - Adán Cabello
- Departamento de Física Aplicada II, Universidad de Sevilla, E-41012 Sevilla, Spain
| | - Jan-Åke Larsson
- Institutionen för Systemteknik, Linköpings Universitet, 581 83 Linköping, Sweden
| | - Paolo Mataloni
- Dipartimento de Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, Roma I-00185, Italy
| | - Gustavo Lima
- 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
| | - Guilherme B Xavier
- 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
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8
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Cuevas A, Carvacho G, Saavedra G, Cariñe J, Nogueira W, Figueroa M, Cabello A, Mataloni P, Lima G, Xavier G. Long-distance distribution of genuine energy-time entanglement. Nat Commun 2013; 4:2871. [PMID: 24287678 PMCID: PMC3868229 DOI: 10.1038/ncomms3871] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Accepted: 11/06/2013] [Indexed: 11/29/2022] Open
Abstract
Any practical realization of entanglement-based quantum communication must be intrinsically secure and able to span long distances avoiding the need of a straight line between the communicating parties. The violation of Bell's inequality offers a method for the certification of quantum links without knowing the inner workings of the devices. Energy-time entanglement quantum communication satisfies all these requirements. However, currently there is a fundamental obstacle with the standard configuration adopted: an intrinsic geometrical loophole that can be exploited to break the security of the communication, in addition to other loopholes. Here we show the first experimental Bell violation with energy-time entanglement distributed over 1 km of optical fibres that is free of this geometrical loophole. This is achieved by adopting a new experimental design, and by using an actively stabilized fibre-based long interferometer. Our results represent an important step towards long-distance secure quantum communication in optical fibres.
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Affiliation(s)
- A. Cuevas
- Departamento de Física, Universidad de Concepción, 160-C, Concepción 4070386, Chile
- Center for Optics and Photonics, Universidad de Concepción, Concepción 4070386, Chile
- MSI-Nucleus for Advanced Optics, Universidad de Concepción, Concepción 4070386, Chile
- These authors contributed equally to this work
| | - G. Carvacho
- Departamento de Física, Universidad de Concepción, 160-C, Concepción 4070386, Chile
- Center for Optics and Photonics, Universidad de Concepción, Concepción 4070386, Chile
- MSI-Nucleus for Advanced Optics, Universidad de Concepción, Concepción 4070386, Chile
- These authors contributed equally to this work
| | - G. Saavedra
- Center for Optics and Photonics, Universidad de Concepción, Concepción 4070386, Chile
- MSI-Nucleus for Advanced Optics, Universidad de Concepción, Concepción 4070386, Chile
- Departamento de Ingeniería Eléctrica, Universidad de Concepción, 160-C, Concepción 4070386, Chile
- These authors contributed equally to this work
| | - J. Cariñe
- Center for Optics and Photonics, Universidad de Concepción, Concepción 4070386, Chile
- Departamento de Ingeniería Eléctrica, Universidad de Concepción, 160-C, Concepción 4070386, Chile
| | - W.A.T. Nogueira
- Departamento de Física, Universidad de Concepción, 160-C, Concepción 4070386, Chile
- Center for Optics and Photonics, Universidad de Concepción, Concepción 4070386, Chile
- MSI-Nucleus for Advanced Optics, Universidad de Concepción, Concepción 4070386, Chile
| | - M. Figueroa
- Center for Optics and Photonics, Universidad de Concepción, Concepción 4070386, Chile
- Departamento de Ingeniería Eléctrica, Universidad de Concepción, 160-C, Concepción 4070386, Chile
| | - A. Cabello
- Departamento de Física Aplicada II, Universidad de Sevilla E-41012, Sevilla, Spain
| | - P. Mataloni
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, Roma I-00185, Italy
- Istituto Nazionale di Ottica (INO-CNR), Largo E. Fermi 6 I-50125, Firenze, Italy
| | - G. Lima
- Departamento de Física, Universidad de Concepción, 160-C, Concepción 4070386, Chile
- Center for Optics and Photonics, Universidad de Concepción, Concepción 4070386, Chile
- MSI-Nucleus for Advanced Optics, Universidad de Concepción, Concepción 4070386, Chile
| | - G.B. Xavier
- Center for Optics and Photonics, Universidad de Concepción, Concepción 4070386, Chile
- MSI-Nucleus for Advanced Optics, Universidad de Concepción, Concepción 4070386, Chile
- Departamento de Ingeniería Eléctrica, Universidad de Concepción, 160-C, Concepción 4070386, Chile
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9
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Xavier GB, von der Weid JP. Stable single-photon interference in a 1 km fiber-optic Mach-Zehnder interferometer with continuous phase adjustment. OPTICS LETTERS 2011; 36:1764-1766. [PMID: 21593883 DOI: 10.1364/ol.36.001764] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We experimentally demonstrate stable and user-adjustable single-photon interference in a 1 km long fiber-optic Mach-Zehnder interferometer, using an active phase control system with the feedback provided by a classical laser. We are able to continuously tune the single-photon phase difference between the interferometer arms using a phase modulator, which is synchronized with the gate window of the single-photon detectors. The phase control system employs a piezoelectric fiber stretcher to stabilize the phase drift in the interferometer. A single-photon net visibility of 0.97 is obtained, yielding future possibilities for experimental realizations of quantum repeaters in optical fibers and violation of Bell's inequalities using genuine energy-time entanglement.
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Affiliation(s)
- G B Xavier
- Center for Telecommunication Studies, Pontifical Catholic University of Rio de Janeiro, R. Marquês de São Vicente 225, Gávea, 22451-900, Rio de Janeiro, Brazil. ‑rio.br
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10
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Wiegner R, Thiel C, von Zanthier J, Agarwal GS. Quantum interference and entanglement of photons that do not overlap in time. OPTICS LETTERS 2011; 36:1512-1514. [PMID: 21499407 DOI: 10.1364/ol.36.001512] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We discuss the possibility of quantum interferences and entanglement of photons that exist at different intervals of time, i.e., one photon being recorded before the other has been created. The corresponding two-photon correlation function is shown to violate Bell's inequalities.
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Affiliation(s)
- R Wiegner
- Institut für Optik, Information und Photonik, Universität Erlangen-Nürnberg, Erlangen, Germany. ‐erlangen.de
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11
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Hayat A, Ginzburg P, Orenstein M. Photon energy entanglement characterization by electronic transition interference. OPTICS EXPRESS 2009; 17:21280-21288. [PMID: 19997367 DOI: 10.1364/oe.17.021280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We propose photon energy qubits and schemes for photon energy entanglement characterization. Bell inequality violation for energy qubits and complete Bell state analysis are demonstrated theoretically. Photon energy superposition state detection is performed by a two-photon absorption interferometer based on electron transition path interference. The scheme can be realized at room-temperature by two-level systems and semiconductor devices.
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Affiliation(s)
- Alex Hayat
- Department of Electrical Engineering, Technion, Haifa 32000, Israel.
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