1
|
Chen L, Wu B, Lu L, Wang K, Lu Y, Zhu S, Ma XS. Observation of quantum nonlocality in Greenberger-Horne-Zeilinger entanglement on a silicon chip. OPTICS EXPRESS 2024; 32:14904-14913. [PMID: 38859154 DOI: 10.1364/oe.515070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 03/23/2024] [Indexed: 06/12/2024]
Abstract
Nonlocality is the defining feature of quantum entanglement. Entangled states with multiple particles are of crucial importance in fundamental tests of quantum physics as well as in many quantum information tasks. One of the archetypal multipartite quantum states, Greenberger-Horne-Zeilinger (GHZ) state, allows one to observe the striking conflict of quantum physics to local realism in the so-called all-versus-nothing way. This is profoundly different from Bell's theorem for two particles, which relies on statistical predictions. Here, we demonstrate an integrated photonic chip capable of generating and manipulating the four-photon GHZ state. We perform a complete characterization of the four-photon GHZ state using quantum state tomography and obtain a state fidelity of 0.729±0.006. We further use the all-versus-nothing test and the Mermin inequalities to witness the quantum nonlocality of GHZ entanglement. Our work paves the way to perform fundamental tests of quantum physics with complex integrated quantum devices.
Collapse
|
2
|
Zawadzki P. Insecurity of Quantum Blockchains Based on Entanglement in Time. ENTROPY (BASEL, SWITZERLAND) 2023; 25:1344. [PMID: 37761643 PMCID: PMC10529257 DOI: 10.3390/e25091344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/07/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023]
Abstract
In this study, the security implications of utilizing the concept of entanglement in time in the quantum representation of a blockchain data structure are investigated. The analysis reveals that the fundamental idea underlying this representation relies on an uncertain interpretation of experimental results. A different perspective is provided by adopting the Copenhagen interpretation, which explains the observed correlations in the experiment without invoking the concept of entanglement in time. According to this interpretation, the qubits responsible for these correlations are not entangled, posing a challenge to the security foundation of the data structure. The study incorporates theoretical analysis, numerical simulations, and experiments using real quantum hardware. By employing a dedicated circuit for detecting genuine entanglement, the existence of entanglement in the process of generating a quantum blockchain is conclusively excluded.
Collapse
Affiliation(s)
- Piotr Zawadzki
- Department of Telecommunications and Teleinformatics, Silesian University of Technology, Akademicka 16, 44-100 Gliwice, Poland
| |
Collapse
|
3
|
Baykusheva DR, Kalthoff MH, Hofmann D, Claassen M, Kennes DM, Sentef MA, Mitrano M. Witnessing Nonequilibrium Entanglement Dynamics in a Strongly Correlated Fermionic Chain. PHYSICAL REVIEW LETTERS 2023; 130:106902. [PMID: 36962013 DOI: 10.1103/physrevlett.130.106902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 01/13/2023] [Accepted: 01/18/2023] [Indexed: 06/18/2023]
Abstract
Many-body entanglement in condensed matter systems can be diagnosed from equilibrium response functions through the use of entanglement witnesses and operator-specific quantum bounds. Here, we investigate the applicability of this approach for detecting entangled states in quantum systems driven out of equilibrium. We use a multipartite entanglement witness, the quantum Fisher information, to study the dynamics of a paradigmatic fermion chain undergoing a time-dependent change of the Coulomb interaction. Our results show that the quantum Fisher information is able to witness distinct signatures of multipartite entanglement both near and far from equilibrium that are robust against decoherence. We discuss implications of these findings for probing entanglement in light-driven quantum materials with time-resolved optical and x-ray scattering methods.
Collapse
Affiliation(s)
| | - Mona H Kalthoff
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science (CFEL), Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Damian Hofmann
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science (CFEL), Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Martin Claassen
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Dante M Kennes
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science (CFEL), Luruper Chaussee 149, 22761 Hamburg, Germany
- Institut für Theorie der Statistischen Physik, RWTH Aachen University, 52056 Aachen, Germany and JARA-Fundamentals of Future Information Technology, 52056 Aachen, Germany
| | - Michael A Sentef
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science (CFEL), Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Matteo Mitrano
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| |
Collapse
|
4
|
Meyer-Scott E, Prasannan N, Dhand I, Eigner C, Quiring V, Barkhofen S, Brecht B, Plenio MB, Silberhorn C. Scalable Generation of Multiphoton Entangled States by Active Feed-Forward and Multiplexing. PHYSICAL REVIEW LETTERS 2022; 129:150501. [PMID: 36269962 DOI: 10.1103/physrevlett.129.150501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 08/26/2022] [Indexed: 06/16/2023]
Abstract
Multiphoton entangled quantum states are key to advancing quantum technologies such as multiparty quantum communications, quantum sensing, or quantum computation. Their scalable generation, however, remains an experimental challenge. Current methods for generating these states rely on stitching together photons from probabilistic sources, and state generation rates drop exponentially in the number of photons. Here, we implement a system based on active feed-forward and multiplexing that addresses this challenge. We demonstrate the scalable generation of four-photon and six-photon Greenberger-Horne-Zeilinger states, increasing generation rates by factors of 9 and 35, respectively. This is consistent with the exponential enhancement compared to the standard nonmultiplexed approach that is predicted by our theory. These results facilitate the realization of practical multiphoton protocols for photonic quantum technologies.
Collapse
Affiliation(s)
- Evan Meyer-Scott
- Paderborn University, Integrated Quantum Optics, Institute for Photonic Quantum Systems (PhoQS), 33098 Paderborn, Germany
| | - Nidhin Prasannan
- Paderborn University, Integrated Quantum Optics, Institute for Photonic Quantum Systems (PhoQS), 33098 Paderborn, Germany
| | - Ish Dhand
- Institut für Theoretische Physik and Center for Integrated Quantum Science and Technology (IQST), University of Ulm, 89069 Ulm, Germany
| | - Christof Eigner
- Paderborn University, Integrated Quantum Optics, Institute for Photonic Quantum Systems (PhoQS), 33098 Paderborn, Germany
| | - Viktor Quiring
- Paderborn University, Integrated Quantum Optics, Institute for Photonic Quantum Systems (PhoQS), 33098 Paderborn, Germany
| | - Sonja Barkhofen
- Paderborn University, Integrated Quantum Optics, Institute for Photonic Quantum Systems (PhoQS), 33098 Paderborn, Germany
| | - Benjamin Brecht
- Paderborn University, Integrated Quantum Optics, Institute for Photonic Quantum Systems (PhoQS), 33098 Paderborn, Germany
| | - Martin B Plenio
- Institut für Theoretische Physik and Center for Integrated Quantum Science and Technology (IQST), University of Ulm, 89069 Ulm, Germany
| | - Christine Silberhorn
- Paderborn University, Integrated Quantum Optics, Institute for Photonic Quantum Systems (PhoQS), 33098 Paderborn, Germany
| |
Collapse
|
5
|
Mao YL, Li ZD, Yu S, Fan J. Test of Genuine Multipartite Nonlocality. PHYSICAL REVIEW LETTERS 2022; 129:150401. [PMID: 36269952 DOI: 10.1103/physrevlett.129.150401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 08/31/2022] [Indexed: 06/16/2023]
Abstract
While Bell nonlocality of a bipartite system is counterintuitive, multipartite nonlocality in our many-body world turns out to be even more so. Recent theoretical study reveals in a theory-agnostic manner that genuine multipartite nonlocal correlations cannot be explained by any causal theory involving fewer-partite nonclassical resources and global shared randomness. Here, we provide a Bell-type inequality as a test for genuine multipartite nonlocality in network by exploiting a matrix representation of the causal structure of a multipartite system. We further present experimental demonstrations that both four-photon GHZ state and generalized four-photon GHZ state significantly violate the inequality, i.e., the observed four-partite correlations resist explanations involving three-way nonlocal resources subject to local operations and common shared randomness, hence confirming that nature is boundless multipartite nonlocal.
Collapse
Affiliation(s)
- Ya-Li Mao
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China
- Center for Advanced Light Source, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Zheng-Da Li
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Sixia Yu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jingyun Fan
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China
- Center for Advanced Light Source, Southern University of Science and Technology, Shenzhen, 518055, China
| |
Collapse
|
6
|
Deterministic Entanglement Swapping with Hybrid Discrete- and Continuous-Variable Systems. PHOTONICS 2022. [DOI: 10.3390/photonics9060368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The study of entanglement between discrete and continuous variables is an important theoretical and experimental topic in quantum information processing, for which entanglement swapping is one of the interesting elements. Entanglement swapping allows two particles without interacting with each other in any way, to form an entangled state by the action of another pair of entangled particles. In this paper, we propose an experimentally feasible scheme to realize deterministic entanglement swapping in the hybrid system with discrete and continuous variables. The process is achieved by preparing two pairs of entangled states, each is formed by a qubit and two quasi-orthogonal coherent state elements of a cavity, performing a Bell-state analysis through nonlocal operations on the continuous variable states of the two cavities, and projecting the two qubits into a maximally entangled state. The present scheme may be applied to other physical systems sustaining such hybrid discrete and continuous forms, providing a typical paradigm for entanglement manipulation through deterministic swapping operations.
Collapse
|
7
|
Chen L, Xiu XM, Dong L, Liu NN, Shen CP, Zhang S, Chen S, Su SL. Direct conversion of Greenberger-Horne-Zeilinger state to Knill-Laflamme-Milburn state in decoherence-free subspace. OPTICS LETTERS 2022; 47:2262-2265. [PMID: 35486775 DOI: 10.1364/ol.458723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 03/29/2022] [Indexed: 06/14/2023]
Abstract
Several schemes are proposed to realize the conversion of photonic polarized-entangled Greenberger-Horne-Zeilinger state to Knill-Laflamme-Milburn state in decoherence-free subspace (DFS) via weak cross-Kerr nonlinearity and X-quadrature homodyne measurement with high fidelity. DFS is introduced to decrease the decoherence effect caused by the coupling between the system and the environment. Optimizations to improve the success rate and utilization of residual states are further investigated. This study indicates important applications for quantum information processing in the future.
Collapse
|
8
|
Tavakoli A, Pozas-Kerstjens A, Luo MX, Renou MO. Bell nonlocality in networks. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:056001. [PMID: 34883470 DOI: 10.1088/1361-6633/ac41bb] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 12/09/2021] [Indexed: 06/13/2023]
Abstract
Bell's theorem proves that quantum theory is inconsistent with local physical models. It has propelled research in the foundations of quantum theory and quantum information science. As a fundamental feature of quantum theory, it impacts predictions far beyond the traditional scenario of the Einstein-Podolsky-Rosen paradox. In the last decade, the investigation of nonlocality has moved beyond Bell's theorem to consider more sophisticated experiments that involve several independent sources which distribute shares of physical systems among many parties in a network. Network scenarios, and the nonlocal correlations that they give rise to, lead to phenomena that have no counterpart in traditional Bell experiments, thus presenting a formidable conceptual and practical challenge. This review discusses the main concepts, methods, results and future challenges in the emerging topic of Bell nonlocality in networks.
Collapse
Affiliation(s)
- Armin Tavakoli
- Institute for Quantum Optics and Quantum Information-IQOQI Vienna, Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna, Austria
- Institute for Atomic and Subatomic Physics, Vienna University of Technology, 1020 Vienna, Austria
| | - Alejandro Pozas-Kerstjens
- Departamento de Análisis Matemático, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Instituto de Ciencias Matemáticas (CSIC-UAM-UC3M-UCM), Madrid, Spain
| | - Ming-Xing Luo
- Information Coding & Transmission Key Laboratory of Sichuan Province, School of Information Science & Technology, Southwest Jiaotong University, Chengdu 610031, People's Republic of China
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Marc-Olivier Renou
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| |
Collapse
|
9
|
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: 2] [Impact Index Per Article: 0.7] [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.
Collapse
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
| |
Collapse
|
10
|
Bai GD, Cui TJ. Representing Quantum Information with Digital Coding Metasurfaces. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2001648. [PMID: 33101865 PMCID: PMC7578880 DOI: 10.1002/advs.202001648] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/19/2020] [Indexed: 05/31/2023]
Abstract
With the development of science and technology, the way to represent information becomes more powerful and diversified. Recent research on digital coding metasurfaces has built an alternative bridge between wave-behaviors and information science. Different from the logic information in traditional circuits, the digital bit in coding metasurfaces is based on wave-structure interaction, which is capable of exploiting multiple degrees of freedom (DoFs). However, to what extent the digital coding metasurface can expand the information representation has not been discussed. In this work, it is shown that classical metasurfaces have the ability to mimic qubit and quantum information. An approach for simulating a two-level spin system with meta-atoms is proposed, from which the superposition for two optical spin states is constructed. It is further proposed that using geometric-phase elements with nonseparable coding states can induce the classical entanglement between polarization and spatial modes, and give the condition to achieve the maximal entanglement. This study expands the information representing range of coding metasurfaces and provides an ultrathin platform to mimic quantum information.
Collapse
Affiliation(s)
- Guo Dong Bai
- State Key Laboratory of Millimeter WaveSoutheast UniversityNanjing210096China
- Institute of Electromagnetic SpaceSoutheast UniversityNanjing210096China
| | - Tie Jun Cui
- State Key Laboratory of Millimeter WaveSoutheast UniversityNanjing210096China
- Institute of Electromagnetic SpaceSoutheast UniversityNanjing210096China
| |
Collapse
|
11
|
Omran A, Levine H, Keesling A, Semeghini G, Wang TT, Ebadi S, Bernien H, Zibrov AS, Pichler H, Choi S, Cui J, Rossignolo M, Rembold P, Montangero S, Calarco T, Endres M, Greiner M, Vuletić V, Lukin MD. Generation and manipulation of Schrödinger cat states in Rydberg atom arrays. Science 2020; 365:570-574. [PMID: 31395778 DOI: 10.1126/science.aax9743] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/08/2019] [Indexed: 11/03/2022]
Abstract
Quantum entanglement involving coherent superpositions of macroscopically distinct states is among the most striking features of quantum theory, but its realization is challenging because such states are extremely fragile. Using a programmable quantum simulator based on neutral atom arrays with interactions mediated by Rydberg states, we demonstrate the creation of "Schrödinger cat" states of the Greenberger-Horne-Zeilinger (GHZ) type with up to 20 qubits. Our approach is based on engineering the energy spectrum and using optimal control of the many-body system. We further demonstrate entanglement manipulation by using GHZ states to distribute entanglement to distant sites in the array, establishing important ingredients for quantum information processing and quantum metrology.
Collapse
Affiliation(s)
- A Omran
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - H Levine
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - A Keesling
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - G Semeghini
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - T T Wang
- Department of Physics, Harvard University, Cambridge, MA 02138, USA.,Department of Physics, Gordon College, Wenham, MA 01984, USA
| | - S Ebadi
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - H Bernien
- Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - A S Zibrov
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - H Pichler
- Department of Physics, Harvard University, Cambridge, MA 02138, USA.,Institute for Theoretical Atomic Molecular and Optical Physics (ITAMP), Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA
| | - S Choi
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA
| | - J Cui
- Forschungszentrum Jülich, Institute of Quantum Control (PGI-8), D-52425 Jülich, Germany
| | - M Rossignolo
- Institute for Quantum Optics and Center of Integrated Quantum Science and Technology (IQST), Universität Ulm, D-89081 Ulm, Germany
| | - P Rembold
- Forschungszentrum Jülich, Institute of Quantum Control (PGI-8), D-52425 Jülich, Germany
| | - S Montangero
- Dipartimento di Fisica e Astronomia "G. Galilei," Università degli Studi di Padova and Istituto Nazionale di Fisica Nucleare (INFN), I-35131 Padova, Italy
| | - T Calarco
- Forschungszentrum Jülich, Institute of Quantum Control (PGI-8), D-52425 Jülich, Germany.,Institute for Theoretical Physics, University of Cologne, D-50937 Cologne, Germany
| | - M Endres
- Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
| | - M Greiner
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - V Vuletić
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - M D Lukin
- Department of Physics, Harvard University, Cambridge, MA 02138, USA.
| |
Collapse
|
12
|
Quantum mechanics with patterns of light: Progress in high dimensional and multidimensional entanglement with structured light. ACTA ACUST UNITED AC 2019. [DOI: 10.1116/1.5112027] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
13
|
Zopf M, Keil R, Chen Y, Yang J, Chen D, Ding F, Schmidt OG. Entanglement Swapping with Semiconductor-Generated Photons Violates Bell's Inequality. PHYSICAL REVIEW LETTERS 2019; 123:160502. [PMID: 31702338 DOI: 10.1103/physrevlett.123.160502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Indexed: 06/10/2023]
Abstract
Transferring entangled states between photon pairs is essential in quantum communication. Semiconductor quantum dots are the leading candidate for generating polarization-entangled photons deterministically. Here we show for the first time swapping of entangled states between two pairs of photons emitted by a single dot. A joint Bell measurement heralds the successful generation of the Bell state Ψ^{+}, yielding a fidelity of 0.81±0.04 and violating the CHSH and Bell inequalities. Our photon source matches atomic quantum memory frequencies, facilitating implementation of hybrid quantum repeaters.
Collapse
Affiliation(s)
- Michael Zopf
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
| | - Robert Keil
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
| | - Yan Chen
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
| | - Jingzhong Yang
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
- Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover, Germany
| | - Disheng Chen
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
| | - Fei Ding
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
- Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover, Germany
| | - Oliver G Schmidt
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
- Material Systems for Nanoelectronics, Technische Universität Chemnitz, 09107 Chemnitz, Germany
| |
Collapse
|
14
|
Proietti M, Pickston A, Graffitti F, Barrow P, Kundys D, Branciard C, Ringbauer M, Fedrizzi A. Experimental test of local observer independence. SCIENCE ADVANCES 2019; 5:eaaw9832. [PMID: 31555731 PMCID: PMC6754223 DOI: 10.1126/sciadv.aaw9832] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 08/21/2019] [Indexed: 05/23/2023]
Abstract
The scientific method relies on facts, established through repeated measurements and agreed upon universally, independently of who observed them. In quantum mechanics the objectivity of observations is not so clear, most markedly exposed in Wigner's eponymous thought experiment where two observers can experience seemingly different realities. The question whether the observers' narratives can be reconciled has only recently been made accessible to empirical investigation, through recent no-go theorems that construct an extended Wigner's friend scenario with four observers. In a state-of-the-art six-photon experiment, we realize this extended Wigner's friend scenario, experimentally violating the associated Bell-type inequality by five standard deviations. If one holds fast to the assumptions of locality and free choice, this result implies that quantum theory should be interpreted in an observer-dependent way.
Collapse
Affiliation(s)
- Massimiliano Proietti
- Scottish Universities Physics Alliance, Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Alexander Pickston
- Scottish Universities Physics Alliance, Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Francesco Graffitti
- Scottish Universities Physics Alliance, Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Peter Barrow
- Scottish Universities Physics Alliance, Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Dmytro Kundys
- Scottish Universities Physics Alliance, Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Cyril Branciard
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - Martin Ringbauer
- Scottish Universities Physics Alliance, Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
- Institut für Experimentalphysik, Universität Innsbruck, 6020 Innsbruck, Austria
| | - Alessandro Fedrizzi
- Scottish Universities Physics Alliance, Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| |
Collapse
|
15
|
Ning W, Huang XJ, Han PR, Li H, Deng H, Yang ZB, Zhong ZR, Xia Y, Xu K, Zheng D, Zheng SB. Deterministic Entanglement Swapping in a Superconducting Circuit. PHYSICAL REVIEW LETTERS 2019; 123:060502. [PMID: 31491139 DOI: 10.1103/physrevlett.123.060502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Indexed: 06/10/2023]
Abstract
Entanglement swapping, the process to entangle two particles without coupling them in any way, is one of the most striking manifestations of the quantum-mechanical nonlocal characteristic. Besides fundamental interest, this process has applications in complex entanglement manipulation and quantum communication. Here we report a high-fidelity, unconditional entanglement swapping experiment in a superconducting circuit. The measured concurrence characterizing the qubit-qubit entanglement produced by swapping is above 0.75, confirming most of the entanglement of one qubit with its partner is deterministically transferred to another qubit that has never interacted with it. We further realize delayed-choice entanglement swapping, showing whether two qubits previously behaved as in an entangled state or as in a separable state is determined by a later choice of the type of measurement on their partners. This is the first demonstration of entanglement-separability duality in a deterministic way.
Collapse
Affiliation(s)
- Wen Ning
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Xin-Jie Huang
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Pei-Rong Han
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Hekang Li
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hui Deng
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhen-Biao Yang
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Zhi-Rong Zhong
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Yan Xia
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| | - Kai Xu
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Dongning Zheng
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Shi-Biao Zheng
- Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
| |
Collapse
|
16
|
Experimental observation of classical analogy of topological entanglement entropy. Nat Commun 2019; 10:1557. [PMID: 30952856 PMCID: PMC6450868 DOI: 10.1038/s41467-019-09584-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 03/07/2019] [Indexed: 11/08/2022] Open
Abstract
Long-range entanglement is an important aspect of the topological orders, so efficient methods to characterize the long-range entanglement are often needed. In this regard, topological entanglement entropy (TEE) is often used for such a purpose but the experimental observation of TEE in a topological order remains a challenge. Here, we propose a scheme to observe TEE in the topological order by constructing specific minimum entropy states (MESs). We then experimentally construct the classical microwave analogs of the MESs and simulate the nontrivial topological order with the TEE in Kitaev toric code, which is in agreement with theoretical predictions. We also experimentally simulate the transition from Z2 topologically ordered state to topologically trivial state.
Collapse
|
17
|
Quantum experiments and graphs II: Quantum interference, computation, and state generation. Proc Natl Acad Sci U S A 2019; 116:4147-4155. [PMID: 30770451 DOI: 10.1073/pnas.1815884116] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We present an approach to describe state-of-the-art photonic quantum experiments using graph theory. There, the quantum states are given by the coherent superpositions of perfect matchings. The crucial observation is that introducing complex weights in graphs naturally leads to quantum interference. This viewpoint immediately leads to many interesting results, some of which we present here. First, we identify an experimental unexplored multiphoton interference phenomenon. Second, we find that computing the results of such experiments is #P-hard, which means it is a classically intractable problem dealing with the computation of a matrix function Permanent and its generalization Hafnian. Third, we explain how a recent no-go result applies generally to linear optical quantum experiments, thus revealing important insights into quantum state generation with current photonic technology. Fourth, we show how to describe quantum protocols such as entanglement swapping in a graphical way. The uncovered bridge between quantum experiments and graph theory offers another perspective on a widely used technology and immediately raises many follow-up questions.
Collapse
|
18
|
Abstract
We experimentally demonstrate that when three single photons transmit through two polarization channels, in a well-defined pre- and postselected ensemble, there are no two photons in the same polarization channel by weak-strength measurement, a counterintuitive quantum counting effect called the quantum pigeonhole paradox. We further show that this effect breaks down in second-order measurement. These results indicate the existence of the quantum pigeonhole paradox and its operating regime.
Collapse
|
19
|
Flamini F, Spagnolo N, Sciarrino F. Photonic quantum information processing: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:016001. [PMID: 30421725 DOI: 10.1088/1361-6633/aad5b2] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Photonic quantum technologies represent a promising platform for several applications, ranging from long-distance communications to the simulation of complex phenomena. Indeed, the advantages offered by single photons do make them the candidate of choice for carrying quantum information in a broad variety of areas with a versatile approach. Furthermore, recent technological advances are now enabling first concrete applications of photonic quantum information processing. The goal of this manuscript is to provide the reader with a comprehensive review of the state of the art in this active field, with a due balance between theoretical, experimental and technological results. When more convenient, we will present significant achievements in tables or in schematic figures, in order to convey a global perspective of the several horizons that fall under the name of photonic quantum information.
Collapse
Affiliation(s)
- Fulvio Flamini
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, I-00185 Roma, Italy
| | | | | |
Collapse
|
20
|
Zhong HS, Li Y, Li W, Peng LC, Su ZE, Hu Y, He YM, Ding X, Zhang W, Li H, Zhang L, Wang Z, You L, Wang XL, Jiang X, Li L, Chen YA, Liu NL, Lu CY, Pan JW. 12-Photon Entanglement and Scalable Scattershot Boson Sampling with Optimal Entangled-Photon Pairs from Parametric Down-Conversion. PHYSICAL REVIEW LETTERS 2018; 121:250505. [PMID: 30608840 DOI: 10.1103/physrevlett.121.250505] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Indexed: 06/09/2023]
Abstract
Entangled-photon sources with simultaneously near-unity heralding efficiency and indistinguishability are the fundamental elements for scalable photonic quantum technologies. We design and realize a degenerate telecommunication wavelength entangled-photon source from an ultrafast pulsed laser pumped spontaneous parametric down-conversion (SPDC), which shows simultaneously 97% heralding efficiency and 96% indistinguishability between independent single photons without narrow-band filtering. Such a beamlike and frequency-uncorrelated SPDC source allows generation of the first 12-photon genuine entanglement with a state fidelity of 0.572±0.024. We further demonstrate a blueprint of scalable scattershot boson sampling using 12 SPDC sources and a 12×12 mode interferometer for three-, four-, and five-boson sampling, which yields count rates more than 4 orders of magnitude higher than all previous SPDC experiments.
Collapse
Affiliation(s)
- Han-Sen Zhong
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yuan Li
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Wei Li
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Li-Chao Peng
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zu-En Su
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yi Hu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yu-Ming He
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xing Ding
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Weijun Zhang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China
| | - Hao Li
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China
| | - Lu Zhang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China
| | - Zhen Wang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China
| | - Lixing You
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China
| | - Xi-Lin Wang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiao Jiang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Li Li
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yu-Ao Chen
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Nai-Le Liu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Chao-Yang Lu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jian-Wei Pan
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| |
Collapse
|
21
|
Wang XL, Luo YH, Huang HL, Chen MC, Su ZE, Liu C, Chen C, Li W, Fang YQ, Jiang X, Zhang J, Li L, Liu NL, Lu CY, Pan JW. 18-Qubit Entanglement with Six Photons' Three Degrees of Freedom. PHYSICAL REVIEW LETTERS 2018; 120:260502. [PMID: 30004724 DOI: 10.1103/physrevlett.120.260502] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Indexed: 05/09/2023]
Abstract
Full control of multiple degrees of freedom of multiple particles represents a fundamental ability for quantum information processing. We experimentally demonstrate an 18-qubit Greenberger-Horne-Zeilinger entanglement by simultaneous exploiting three different degrees of freedom of six photons, including their paths, polarization, and orbital angular momentum. We develop high-stability interferometers for reversible quantum logic operations between the photons' different degrees of freedom with precision and efficiencies close to unity, enabling simultaneous readout of 2^{18}=262 144 outcome combinations of the 18-qubit state. A state fidelity of 0.708±0.016 is measured, confirming the genuine entanglement of all 18 qubits.
Collapse
Affiliation(s)
- Xi-Lin Wang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; and CAS-Alibaba Quantum Computing Laboratory, Shanghai 201315, China
| | - Yi-Han Luo
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; and CAS-Alibaba Quantum Computing Laboratory, Shanghai 201315, China
| | - He-Liang Huang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; and CAS-Alibaba Quantum Computing Laboratory, Shanghai 201315, China
| | - Ming-Cheng Chen
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; and CAS-Alibaba Quantum Computing Laboratory, Shanghai 201315, China
| | - Zu-En Su
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; and CAS-Alibaba Quantum Computing Laboratory, Shanghai 201315, China
| | - Chang Liu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; and CAS-Alibaba Quantum Computing Laboratory, Shanghai 201315, China
| | - Chao Chen
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; and CAS-Alibaba Quantum Computing Laboratory, Shanghai 201315, China
| | - Wei Li
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; and CAS-Alibaba Quantum Computing Laboratory, Shanghai 201315, China
| | - Yu-Qiang Fang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; and CAS-Alibaba Quantum Computing Laboratory, Shanghai 201315, China
| | - Xiao Jiang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; and CAS-Alibaba Quantum Computing Laboratory, Shanghai 201315, China
| | - Jun Zhang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; and CAS-Alibaba Quantum Computing Laboratory, Shanghai 201315, China
| | - Li Li
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; and CAS-Alibaba Quantum Computing Laboratory, Shanghai 201315, China
| | - Nai-Le Liu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; and CAS-Alibaba Quantum Computing Laboratory, Shanghai 201315, China
| | - Chao-Yang Lu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; and CAS-Alibaba Quantum Computing Laboratory, Shanghai 201315, China
| | - Jian-Wei Pan
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; CAS Centre for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China; and CAS-Alibaba Quantum Computing Laboratory, Shanghai 201315, China
| |
Collapse
|
22
|
Khoshnegar M, Huber T, Predojević A, Dalacu D, Prilmüller M, Lapointe J, Wu X, Tamarat P, Lounis B, Poole P, Weihs G, Majedi H. A solid state source of photon triplets based on quantum dot molecules. Nat Commun 2017; 8:15716. [PMID: 28604705 PMCID: PMC5472777 DOI: 10.1038/ncomms15716] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 04/21/2017] [Indexed: 11/30/2022] Open
Abstract
Producing advanced quantum states of light is a priority in quantum information technologies. In this context, experimental realizations of multipartite photon states would enable improved tests of the foundations of quantum mechanics as well as implementations of complex quantum optical networks and protocols. It is favourable to directly generate these states using solid state systems, for simpler handling and the promise of reversible transfer of quantum information between stationary and flying qubits. Here we use the ground states of two optically active coupled quantum dots to directly produce photon triplets. The formation of a triexciton in these ground states leads to a triple cascade recombination and sequential emission of three photons with strong correlations. We record 65.62 photon triplets per minute under continuous-wave pumping, surpassing rates of earlier reported sources. Our structure and data pave the way towards implementing multipartite photon entanglement and multi-qubit readout schemes in solid state devices. Multipartite photon states are desirable in quantum information technology but their generation in optical systems is less efficient with poor scaling. Here the authors demonstrate time-ordered photon triplets from a quantum dot molecule in a direct generation process with increased efficiency.
Collapse
Affiliation(s)
- Milad Khoshnegar
- Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.,Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.,Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Tobias Huber
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Ana Predojević
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Dan Dalacu
- National Research Council of Canada, 1200 Montreal Road, Ottawa, Ontario, Canada K1A 0R6
| | - Maximilian Prilmüller
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Jean Lapointe
- National Research Council of Canada, 1200 Montreal Road, Ottawa, Ontario, Canada K1A 0R6
| | - Xiaohua Wu
- National Research Council of Canada, 1200 Montreal Road, Ottawa, Ontario, Canada K1A 0R6
| | - Philippe Tamarat
- Université Bordeaux, LP2N Institut d'Optique and CNRS, Talence F-33405, France
| | - Brahim Lounis
- Université Bordeaux, LP2N Institut d'Optique and CNRS, Talence F-33405, France
| | - Philip Poole
- National Research Council of Canada, 1200 Montreal Road, Ottawa, Ontario, Canada K1A 0R6
| | - Gregor Weihs
- Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.,Institut für Experimentalphysik, Universität Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Hamed Majedi
- Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.,Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| |
Collapse
|
23
|
Krenn M, Hochrainer A, Lahiri M, Zeilinger A. Entanglement by Path Identity. PHYSICAL REVIEW LETTERS 2017; 118:080401. [PMID: 28282180 DOI: 10.1103/physrevlett.118.080401] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Indexed: 05/11/2023]
Abstract
Quantum entanglement is one of the most prominent features of quantum mechanics and forms the basis of quantum information technologies. Here we present a novel method for the creation of quantum entanglement in multipartite and high-dimensional systems. The two ingredients are (i) superposition of photon pairs with different origins and (ii) aligning photons such that their paths are identical. We explain the experimentally feasible creation of various classes of multiphoton entanglement encoded in polarization as well as in high-dimensional Hilbert spaces-starting only from nonentangled photon pairs. For two photons, arbitrary high-dimensional entanglement can be created. The idea of generating entanglement by path identity could also apply to quantum entities other than photons. We discovered the technique by analyzing the output of a computer algorithm. This shows that computer designed quantum experiments can be inspirations for new techniques.
Collapse
Affiliation(s)
- Mario Krenn
- Vienna Center for Quantum Science & Technology (VCQ), Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria and Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna, Austria
| | - Armin Hochrainer
- Vienna Center for Quantum Science & Technology (VCQ), Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria and Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna, Austria
| | - Mayukh Lahiri
- Vienna Center for Quantum Science & Technology (VCQ), Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria and Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna, Austria
| | - Anton Zeilinger
- Vienna Center for Quantum Science & Technology (VCQ), Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria and Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna, Austria
| |
Collapse
|
24
|
De Assis PL, Carvalho MAD, Berruezo LP, Ferraz J, Pádua S. Generation of two pairs of qudits using four photons and a single degree of freedom. OPTICS EXPRESS 2016; 24:30149-30163. [PMID: 28059292 DOI: 10.1364/oe.24.030149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Qudits, d-level quantum systems, have been shown to provide a better resource for quantum key distribution and other Quantum Information protocols. It is customary to generate photonic qudits using more than one degree of freedom of the same photon. In much the same way, multi-qubit states are generated using only a pair of photons and ingenious ways to manipulate more than one degree of freedom independently. In contrast to such costly implementations in terms of quantum resources, we present the controlled generation of two copies of two-qudit states using four photons and a single degree of freedom, transverse momentum. The degree of entanglement within each pair was inferred by exploiting the availability of two copies of the same state, without the need of a full tomographic reconstruction of the states, and both highly-entangled and separable states were generated. We show theoretically that the set of states obtainable using our setup is very diverse, ranging from maximally entangled states of qudits to separable states.
Collapse
|
25
|
Zhang C, Huang YF, Zhang CJ, Wang J, Liu BH, Li CF, Guo GC. Generation and applications of an ultrahigh-fidelity four-photon Greenberger-Horne-Zeilinger state. OPTICS EXPRESS 2016; 24:27059-27069. [PMID: 27906280 DOI: 10.1364/oe.24.027059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
High-quality entangled photon pairs generated via spontaneous parametric down-conversion have made great contributions to the modern quantum information science and the fundamental tests of quantum mechanics. However, the quality of the entangled states decreases sharply when moving from biphoton to multiphoton experiments, mainly due to the lack of interactions between photons. Here, for the first time, we generate a four-photon Greenberger-Horne-Zeilinger state with a fidelity of 98%, which is even comparable to the best fidelity of biphoton entangled states. Thus, it enables us to demonstrate an ultrahigh-fidelity entanglement swapping-the key ingredient in various quantum information tasks. Our results push the fidelity of multiphoton entanglement generation to a new level and would be useful in some demanding tasks, e.g., we successfully demonstrate the genuine multipartite nonlocality of the observed state in the nonsignaling scenario by violating a novel Hardy-like inequality, which requires very high state-fidelity.
Collapse
|
26
|
Cui WX, Hu S, Wang HF, Zhu AD, Zhang S. Deterministic conversion of a four-photon GHZ state to a W state via homodyne measurement. OPTICS EXPRESS 2016; 24:15319-15327. [PMID: 27410808 DOI: 10.1364/oe.24.015319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We propose a specific method for converting a four-photon Greenberger-Horne-Zeilinger (GHZ) state to a W state in a deterministic way by using linear optical elements, cross-Kerr nonlinearities, and homodyne measurement. We consider the effects of the quadrature homodyne measurements on the fidelity of the W state and the experimental feasibility of the proposed scheme. This might provide great prospects for converting multipartite entangled states into each other for future optical quantum information processing (QIP).
Collapse
|
27
|
Exploration of multiphoton entangled states by using weak nonlinearities. Sci Rep 2016; 6:19116. [PMID: 26751044 PMCID: PMC4707534 DOI: 10.1038/srep19116] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 12/04/2015] [Indexed: 11/18/2022] Open
Abstract
We propose a fruitful scheme for exploring multiphoton entangled states based on linear optics and weak nonlinearities. Compared with the previous schemes the present method is more feasible because there are only small phase shifts instead of a series of related functions of photon numbers in the process of interaction with Kerr nonlinearities. In the absence of decoherence we analyze the error probabilities induced by homodyne measurement and show that the maximal error probability can be made small enough even when the number of photons is large. This implies that the present scheme is quite tractable and it is possible to produce entangled states involving a large number of photons.
Collapse
|
28
|
Abstract
The Hong-Ou-Mandel (HOM) effect is widely regarded as the quintessential quantum interference phenomenon in optics. In this work we examine how nonlinearity can smear statistical photon bunching in the HOM interferometer. We model both the nonlinearity and a balanced beam splitter with a single two-level system and calculate a finite probability of anti-bunching arising in this geometry. We thus argue that the presence of such nonlinearity would reduce the visibility in the standard HOM setup, offering some explanation for the diminution of the HOM visibility observed in many experiments. We use the same model to show that the nonlinearity affects a resonant two-photon propagation through a two-level impurity in a waveguide due to a “weak photon blockade” caused by the impossibility of double-occupancy and argue that this effect might be stronger for multi-photon propagation.
Collapse
|
29
|
Goyal SK, Boukama-Dzoussi PE, Ghosh S, Roux FS, Konrad T. Qudit-teleportation for photons with linear optics. Sci Rep 2014; 4:4543. [PMID: 24686274 PMCID: PMC3971412 DOI: 10.1038/srep04543] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 03/04/2014] [Indexed: 11/24/2022] Open
Abstract
Quantum Teleportation, the transfer of the state of one quantum system to another without direct interaction between both systems, is an important way to transmit information encoded in quantum states and to generate quantum correlations (entanglement) between remote quantum systems. So far, for photons, only superpositions of two distinguishable states (one “qubit”) could be teleported. Here we show how to teleport a “qudit”, i.e. a superposition of an arbitrary number d of distinguishable states present in the orbital angular momentum of a single photon using d beam splitters and d additional entangled photons. The same entanglement resource might also be employed to collectively teleport the state of d/2 photons at the cost of one additional entangled photon per qubit. This is superior to existing schemes for photonic qubits, which require an additional pair of entangled photons per qubit.
Collapse
Affiliation(s)
- Sandeep K Goyal
- 1] School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa [2] The Institute of Mathematical Sciences, CIT Campus Taramani, Chennai 600 113, India
| | - Patricia E Boukama-Dzoussi
- School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa
| | - Sibasish Ghosh
- The Institute of Mathematical Sciences, CIT Campus Taramani, Chennai 600 113, India
| | - Filippus S Roux
- CSIR National Laser Centre, PO Box 395, Pretoria 0001, South Africa
| | - Thomas Konrad
- 1] School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa [2] National Institute of Theoretical Physics (NITheP), University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa
| |
Collapse
|
30
|
Walter M, Doran B, Gross D, Christandl M. Entanglement Polytopes: Multiparticle Entanglement from Single-Particle Information. Science 2013; 340:1205-8. [DOI: 10.1126/science.1232957] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Michael Walter
- Institute for Theoretical Physics, Eidgenössische Technische Hochschule (ETH) Zürich, Wolfgang-Pauli-Strasse 27, 8093 Zürich, Switzerland
| | - Brent Doran
- Department of Mathematics, ETH Zürich, Rämistrasse 101, 8092 Zürich, Switzerland
| | - David Gross
- Institute for Physics, University of Freiburg, Rheinstrasse 10, 79104 Freiburg, Germany
| | - Matthias Christandl
- Department of Mathematics, ETH Zürich, Rämistrasse 101, 8092 Zürich, Switzerland
| |
Collapse
|
31
|
Megidish E, Shacham T, Halevy A, Dovrat L, Eisenberg HS. Resource efficient source of multiphoton polarization entanglement. PHYSICAL REVIEW LETTERS 2012; 109:080504. [PMID: 23002730 DOI: 10.1103/physrevlett.109.080504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Indexed: 06/01/2023]
Abstract
Current photon entangling schemes require resources that grow with the photon number. We present a new approach that generates quantum entanglement between many photons, using only a single source of entangled photon pairs. The different spatial modes, one for each photon as required by other schemes, are replaced by different time slots of only two spatial modes. States of any number of photons are generated with the same setup, solving the scalability problem caused by the previous need for extra resources. Consequently, entangled photon states of larger numbers than before are practically realizable.
Collapse
Affiliation(s)
- E Megidish
- Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | | | | | | | | |
Collapse
|
32
|
Huang YF, Liu BH, Peng L, Li YH, Li L, Li CF, Guo GC. Experimental generation of an eight-photon Greenberger–Horne–Zeilinger state. Nat Commun 2011; 2:546. [DOI: 10.1038/ncomms1556] [Citation(s) in RCA: 137] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 10/19/2011] [Indexed: 11/09/2022] Open
|
33
|
Halevy A, Megidish E, Dovrat L, Eisenberg HS, Becker P, Bohatý L. The biaxial nonlinear crystal BiB₃O₆ as a polarization entangled photon source using non-collinear type-II parametric down-conversion. OPTICS EXPRESS 2011; 19:20420-20434. [PMID: 21997051 DOI: 10.1364/oe.19.020420] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We describe the full characterization of the biaxial nonlinear crystal BiB₃O₆ (BiBO) as a polarization entangled photon source using non-collinear type-II parametric down-conversion. We consider the relevant parameters for crystal design, such as cutting angles, polarization of the photons, effective nonlinearity, spatial and temporal walk-offs, crystal thickness and the effect of the pump laser bandwidth. Experimental results showing entanglement generation with high rates and a comparison to the well investigated β-BaB₂O₄ (BBO) crystal are presented as well. Changing the down-conversion crystal of a polarization entangled photon source from BBO to BiBO enhances the generation rate as if the pump power was increased by 2.5 times. Such an improvement is currently required for the generation of multiphoton entangled states.
Collapse
Affiliation(s)
- A Halevy
- Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | | | | | | | | | | |
Collapse
|
34
|
Afek I, Ambar O, Silberberg Y. Correlated multiphoton holes: absence of multiphoton coincidence events. PHYSICAL REVIEW LETTERS 2010; 105:093603. [PMID: 20868159 DOI: 10.1103/physrevlett.105.093603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Revised: 07/25/2010] [Indexed: 05/29/2023]
Abstract
We generate bipartite states of light which exhibit an absence of multiphoton coincidence events between two modes amid a constant background flux. These "correlated photon holes" are produced by mixing a coherent state and relatively weak spontaneous parametric down-conversion by using a balanced beam splitter. Correlated holes with arbitrarily high photon numbers may be obtained by adjusting the relative phase and amplitude of the inputs. We measure states of up to five photons and verify their nonclassicality. The scheme provides a route for observation of high-photon-number nonclassical correlations without requiring intense quantum resources.
Collapse
Affiliation(s)
- I Afek
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel.
| | | | | |
Collapse
|
35
|
Klempt C, Topic O, Gebreyesus G, Scherer M, Henninger T, Hyllus P, Ertmer W, Santos L, Arlt JJ. Parametric amplification of vacuum fluctuations in a spinor condensate. PHYSICAL REVIEW LETTERS 2010; 104:195303. [PMID: 20866973 DOI: 10.1103/physrevlett.104.195303] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Revised: 04/02/2010] [Indexed: 05/29/2023]
Abstract
Parametric amplification of vacuum fluctuations is crucial in modern quantum optics, enabling the creation of squeezing and entanglement. We demonstrate the parametric amplification of vacuum fluctuations for matter waves using a spinor F=2 87Rb condensate. Interatomic interactions lead to correlated pair creation in the mF=±1 states from an initial mF=0 condensate, which acts as a vacuum for mF≠0. Although this pair creation from a pure mF=0 condensate is ideally triggered by vacuum fluctuations, unavoidable spurious initial mF=±1 atoms induce a classical seed which may become the dominant triggering mechanism. We show that pair creation is insensitive to a classical seed for sufficiently large magnetic fields, demonstrating the dominant role of vacuum fluctuations. The presented system thus provides a direct path towards the generation of nonclassical states of matter.
Collapse
Affiliation(s)
- C Klempt
- Institut für Quantenoptik, Leibniz Universität Hannover, D-30167 Hannover, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Xue Y, Yoshizawa A, Tsuchida H. Hong-Ou-Mandel dip measurements of polarization-entangled photon pairs at 1550 nm. OPTICS EXPRESS 2010; 18:8182-8186. [PMID: 20588663 DOI: 10.1364/oe.18.008182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We performed a quantum interference experiment using two polarization-entangled photon pairs at 1550 nm, created in periodically poled lithium niobate waveguides. Using four-fold coincidences, a Hong-Ou-Mandel dip at diagonal polarization was observed with a visibility of 74.5% before subtracting accidental coincidences. This experiment lays a foundation for demonstrating polarization-based entanglement swapping and for realizing a quantum relay.
Collapse
Affiliation(s)
- Yinghong Xue
- Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST),1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan.
| | | | | |
Collapse
|
37
|
|
38
|
Lu CY, Yang T, Pan JW. Experimental multiparticle entanglement swapping for quantum networking. PHYSICAL REVIEW LETTERS 2009; 103:020501. [PMID: 19659188 DOI: 10.1103/physrevlett.103.020501] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Indexed: 05/28/2023]
Abstract
This Letter reports the first experimental demonstration of Greenberger-Horne-Zeilinger (GHZ) entanglement swapping. We start with three pairs of entangled photons. Upon projection of three single photons, each from an entangled pair, into a GHZ state, the other three originally independent photons are entangled in a GHZ state-creation of multiparticle entanglement without any direct interaction. This scheme may facilitate networks for quantum telephone exchange, multiparty quantum communication and distributed quantum computation.
Collapse
Affiliation(s)
- Chao-Yang Lu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | | | | |
Collapse
|
39
|
Bastin T, Thiel C, von Zanthier J, Lamata L, Solano E, Agarwal GS. Operational determination of multiqubit entanglement classes via tuning of local operations. PHYSICAL REVIEW LETTERS 2009; 102:053601. [PMID: 19257511 DOI: 10.1103/physrevlett.102.053601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2008] [Indexed: 05/27/2023]
Abstract
We present a physical setup with which it is possible to produce arbitrary symmetric long-lived multiqubit entangled states in the internal ground levels of photon emitters, including the paradigmatic Greenberger-Horne-Zeilinger and W states. In the case of three emitters, where each tripartite entangled state belongs to one of two well-defined entanglement classes, we prove a one-to-one correspondence between well-defined sets of experimental parameters, i.e., locally tunable polarizer orientations, and multiqubit entanglement classes inside the symmetric subspace.
Collapse
Affiliation(s)
- T Bastin
- Institut de Physique Nucléaire, Atomique et de Spectroscopie, Université de Liège, 4000 Liège, Belgium
| | | | | | | | | | | |
Collapse
|
40
|
Lu CY, Gao WB, Gühne O, Zhou XQ, Chen ZB, Pan JW. Demonstrating anyonic fractional statistics with a six-qubit quantum simulator. PHYSICAL REVIEW LETTERS 2009; 102:030502. [PMID: 19257336 DOI: 10.1103/physrevlett.102.030502] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Indexed: 05/27/2023]
Abstract
Anyons are exotic quasiparticles living in two dimensions that do not fit into the usual categories of fermions and bosons, but obey a new form of fractional statistics. Following a recent proposal [Phys. Rev. Lett. 98, 150404 (2007)], we present an experimental demonstration of the fractional statistics of anyons in the Kitaev spin lattice model using a photonic quantum simulator. We dynamically create the ground state and excited states (which are six-qubit graph states) of the Kitaev model Hamiltonian, and implement the anyonic braiding and fusion operations by single-qubit rotations. A phase shift of pi related to the anyon braiding is observed, confirming the prediction of the fractional statistics of Abelian 1/2 anyons.
Collapse
Affiliation(s)
- Chao-Yang Lu
- Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230026, China
| | | | | | | | | | | |
Collapse
|
41
|
Goebel AM, Wagenknecht C, Zhang Q, Chen YA, Chen K, Schmiedmayer J, Pan JW. Multistage entanglement swapping. PHYSICAL REVIEW LETTERS 2008; 101:080403. [PMID: 18764594 DOI: 10.1103/physrevlett.101.080403] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Indexed: 05/26/2023]
Abstract
We report an experimental demonstration of entanglement swapping over two quantum stages. By successful realizations of two cascaded photonic entanglement swapping processes, entanglement is generated and distributed between two photons, that originate from independent sources and do not share any common past. In the experiment we use three pairs of polarization entangled photons and conduct two Bell-state measurements: one between the first and second pair, and one between the second and third pair. This results in projecting the remaining two outgoing photons from pair 1 and 3 into an entangled state, as characterized by an entanglement witness. The experiment represents an important step towards a full quantum repeater where multiple entanglement swapping is a key ingredient.
Collapse
Affiliation(s)
- Alexander M Goebel
- Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 12, 69120 Heidelberg, Germany
| | | | | | | | | | | | | |
Collapse
|
42
|
Zipper E, Kurpas M, Dajka J, Kuś M. Entanglement of distant flux qubits mediated by non-classical electromagnetic field. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2008; 20:275219. [PMID: 21694380 DOI: 10.1088/0953-8984/20/27/275219] [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
The mechanism for entanglement of two flux qubits each interacting with a single mode electromagnetic field is discussed. By performing a Bell state measurement (BSM) on photons we find the two qubits in an entangled state depending on the system parameters. We discuss the results for two initial states and take into consideration the influence of decoherence.
Collapse
Affiliation(s)
- E Zipper
- Institute of Physics, University of Silesia, Ulica Uniwersytecka 4, 40-007 Katowice, Poland
| | | | | | | |
Collapse
|
43
|
Wieczorek W, Schmid C, Kiesel N, Pohlner R, Gühne O, Weinfurter H. Experimental observation of an entire family of four-photon entangled states. PHYSICAL REVIEW LETTERS 2008; 101:010503. [PMID: 18764097 DOI: 10.1103/physrevlett.101.010503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Indexed: 05/26/2023]
Abstract
A single linear-optical setup is used to observe an entire family of four-photon entangled states. This approach breaks with the inflexibility of present linear-optical setups usually designed for the observation of a particular multipartite entangled state only. The family includes several prominent entangled states that are known to be highly relevant for quantum information applications.
Collapse
Affiliation(s)
- Witlef Wieczorek
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany.
| | | | | | | | | | | |
Collapse
|
44
|
Thiel C, von Zanthier J, Bastin T, Solano E, Agarwal GS. Generation of symmetric Dicke states of remote qubits with linear optics. PHYSICAL REVIEW LETTERS 2007; 99:193602. [PMID: 18233076 DOI: 10.1103/physrevlett.99.193602] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Indexed: 05/25/2023]
Abstract
We propose a method for generating all symmetric Dicke states, either in the long-lived internal levels of N massive particles or in the polarization degrees of freedom of photonic qubits, using linear optical tools only. By means of a suitable multiphoton detection technique, erasing Welcher-Weg information, our proposed scheme allows the generation and measurement of an important class of entangled multiqubit states.
Collapse
Affiliation(s)
- C Thiel
- Institut für Optik, Information und Photonik, Max-Planck Forschungsgruppe, Universität Erlangen-Nürnberg, 91058, Erlangen, Germany.
| | | | | | | | | |
Collapse
|
45
|
Kiesel N, Schmid C, Tóth G, Solano E, Weinfurter H. Experimental observation of four-photon entangled Dicke state with high fidelity. PHYSICAL REVIEW LETTERS 2007; 98:063604. [PMID: 17358941 DOI: 10.1103/physrevlett.98.063604] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2006] [Indexed: 05/14/2023]
Abstract
We present the experimental observation of the symmetric four-photon entangled Dicke state with two excitations |D_{4};{(2)}. A simple experimental setup allowed quantum state tomography yielding a fidelity as high as 0.844+/-0.008. We study the entanglement persistency of the state using novel witness operators and focus on the demonstration of a remarkable property: depending on the orientation of a measurement on one photon, the remaining three photons are projected into both inequivalent classes of genuine tripartite entanglement, the Greenberger-Horne-Zeilinger and W class. Furthermore, we discuss possible applications of |D_{4};{(2)} in quantum communication.
Collapse
Affiliation(s)
- N Kiesel
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany
| | | | | | | | | |
Collapse
|
46
|
Chen YA, Yang T, Zhang AN, Zhao Z, Cabello A, Pan JW. Experimental violation of Bell's inequality beyond Tsirelson's bound. PHYSICAL REVIEW LETTERS 2006; 97:170408. [PMID: 17155452 DOI: 10.1103/physrevlett.97.170408] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Indexed: 05/12/2023]
Abstract
The correlations between two qubits belonging to a three-qubit system can violate the Clauser-Horne-Shimony-Holt-Bell inequality beyond Tsirelson's bound [A. Cabello, Phys. Rev. Lett. 88, 060403 (2002)]. We experimentally demonstrate such a violation by 7 standard deviations by using a three-photon polarization-entangled Greenberger-Horne-Zeilinger state produced by Type-II spontaneous parametric down-conversion. In addition, using part of our results, we obtain a violation of the Mermin inequality by 39 standard deviations.
Collapse
Affiliation(s)
- Yu-Ao Chen
- Physikalisches Institut, Universität Heidelberg, Philosophenweg 12, D-69120 Heidelberg, Germany.
| | | | | | | | | | | |
Collapse
|
47
|
|
48
|
Barbieri M, De Martini F, Mataloni P, Vallone G, Cabello A. Enhancing the violation of the einstein-podolsky-rosen local realism by quantum hyperentanglement. PHYSICAL REVIEW LETTERS 2006; 97:140407. [PMID: 17155228 DOI: 10.1103/physrevlett.97.140407] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Indexed: 05/12/2023]
Abstract
Mermin's observation [Phys. Rev. Lett. 65, 1838 (1990)] that the magnitude of the violation of local realism, defined as the ratio between the quantum prediction and the classical bound, can grow exponentially with the size of the system is demonstrated using two-photon hyperentangled states entangled in polarization and path degrees of freedom, and local measurements of polarization and path simultaneously.
Collapse
Affiliation(s)
- Marco Barbieri
- Dipartimento di Fisica dell'Università La Sapienza and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, 00185 Roma, Italy
| | | | | | | | | |
Collapse
|
49
|
Bodiya TP, Duan LM. Scalable generation of graph-state entanglement through realistic linear optics. PHYSICAL REVIEW LETTERS 2006; 97:143601. [PMID: 17155249 DOI: 10.1103/physrevlett.97.143601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Indexed: 05/12/2023]
Abstract
We propose a scheme for efficient construction of graph states using realistic linear optics, imperfect photon source, and single-photon detectors. For any many-body entanglement represented by tree-graph states, we prove that the overall preparation and detection efficiency scales nearly polynomially with the size of the graph, no matter how small the efficiencies for the photon source and the detectors.
Collapse
Affiliation(s)
- T P Bodiya
- FOCUS Center and MCTP, Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | | |
Collapse
|
50
|
Aolita L, Mintert F. Measuring multipartite concurrence with a single factorizable observable. PHYSICAL REVIEW LETTERS 2006; 97:050501. [PMID: 17026084 DOI: 10.1103/physrevlett.97.050501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Indexed: 05/12/2023]
Abstract
We show that, for any composite system with an arbitrary number of finite-dimensional subsystems, it is possible to directly measure the multipartite concurrence of pure states by detecting only one single factorizable observable, provided that two copies of the composite state are available. This result can be immediately put into practice in trapped-ion and entangled-photon experiments.
Collapse
Affiliation(s)
- Leandro Aolita
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ, Brazil.
| | | |
Collapse
|