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Xing WB, Hu XM, Guo Y, Liu BH, Li CF, Guo GC. Preparation of multiphoton high-dimensional GHZ states. OPTICS EXPRESS 2023; 31:24887-24896. [PMID: 37475305 DOI: 10.1364/oe.494850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 06/28/2023] [Indexed: 07/22/2023]
Abstract
The physics associated with multipartite high-dimensional entanglement is different from that of multipartite two-dimensional entanglement. Therefore, preparing multipartite high-dimensional entanglements with linear optics is challenging. This study proposes a preparation protocol of multiphoton GHZ state with arbitrary dimensions for optical systems. Auxiliary entanglements realize a high-dimensional entanglement gate to connect the high-dimensional entangled pairs to a multipartite high-dimensional GHZ state. Specifically, we use the path degrees of freedom of photons to prepare a four-partite, three-dimensional GHZ state. Our method can be extended to other degrees of freedom to generate arbitrary GHZ entanglements in any dimension.
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2
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Qian K, Wang K, Chen L, Hou Z, Krenn M, Zhu S, Ma XS. Multiphoton non-local quantum interference controlled by an undetected photon. Nat Commun 2023; 14:1480. [PMID: 36932077 PMCID: PMC10023773 DOI: 10.1038/s41467-023-37228-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 03/08/2023] [Indexed: 03/18/2023] Open
Abstract
The interference of quanta lies at the heart of quantum physics. The multipartite generalization of single-quanta interference creates entanglement, the coherent superposition of states shared by several quanta. Entanglement allows non-local correlations between many quanta and hence is a key resource for quantum information technology. Entanglement is typically considered to be essential for creating non-local quantum interference. Here, we show that this is not the case and demonstrate multiphoton non-local quantum interference that does not require entanglement of any intrinsic properties of the photons. We harness the superposition of the physical origin of a four-photon product state, which leads to constructive and destructive interference with the photons' mere existence. With the intrinsic indistinguishability in the generation process of photons, we realize four-photon frustrated quantum interference. This allows us to observe the following noteworthy difference to quantum entanglement: We control the non-local multipartite quantum interference with a photon that we never detect, which does not require quantum entanglement. These non-local properties pave the way for the studies of foundations of quantum physics and potential applications in quantum technologies.
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Affiliation(s)
- Kaiyi Qian
- National Laboratory of Solid-state Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Kai Wang
- National Laboratory of Solid-state Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
| | - Leizhen Chen
- National Laboratory of Solid-state Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Zhaohua Hou
- National Laboratory of Solid-state Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Mario Krenn
- Max Planck Institute for the Science of Light (MPL), Erlangen, Germany.
| | - Shining Zhu
- National Laboratory of Solid-state Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Xiao-Song Ma
- National Laboratory of Solid-state Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China. .,Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China. .,Hefei National Laboratory, Hefei, 230088, China.
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3
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Ławniczak M, Akhshani A, Farooq O, Białous M, Bauch S, Dietz B, Sirko L. Distributions of the Wigner reaction matrix for microwave networks with symplectic symmetry in the presence of absorption. Phys Rev E 2023; 107:024203. [PMID: 36932527 DOI: 10.1103/physreve.107.024203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 01/24/2023] [Indexed: 02/09/2023]
Abstract
We report on experimental studies of the distribution of the reflection coefficients, and the imaginary and real parts of Wigner's reaction (K) matrix employing open microwave networks with symplectic symmetry and varying size of absorption. The results are compared to analytical predictions derived for the single-channel scattering case within the framework of random-matrix theory (RMT). Furthermore, we performed Monte Carlo simulations based on the Heidelberg approach for the scattering (S) and K matrix of open quantum-chaotic systems and the two-point correlation function of the S-matrix elements. The analytical results and the Monte Carlo simulations depend on the size of absorption. To verify them, we performed experiments with microwave networks for various absorption strengths. We show that deviations from RMT predictions observed in the spectral properties of the corresponding closed quantum graph and attributed to the presence of nonuniversal short periodic orbits does not have any visible effects on the distributions of the reflection coefficients and the K and S matrices associated with the corresponding open quantum graph.
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Affiliation(s)
- Michał Ławniczak
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02-668 Warsaw, Poland
| | - Afshin Akhshani
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02-668 Warsaw, Poland
| | - Omer Farooq
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02-668 Warsaw, Poland
| | - Małgorzata Białous
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02-668 Warsaw, Poland
| | - Szymon Bauch
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02-668 Warsaw, Poland
| | - Barbara Dietz
- Lanzhou Center for Theoretical Physics and the Gansu Provincial Key Laboratory of Theoretical Physics, Lanzhou University, Lanzhou, Gansu 730000, China.,Center for Theoretical Physics of Complex Systems, Institute for Basic Science (IBS), Daejeon 34126, Korea
| | - Leszek Sirko
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02-668 Warsaw, Poland
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Krenn M, Pollice R, Guo SY, Aldeghi M, Cervera-Lierta A, Friederich P, dos Passos Gomes G, Häse F, Jinich A, Nigam A, Yao Z, Aspuru-Guzik A. On scientific understanding with artificial intelligence. NATURE REVIEWS. PHYSICS 2022; 4:761-769. [PMID: 36247217 PMCID: PMC9552145 DOI: 10.1038/s42254-022-00518-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/30/2022] [Indexed: 05/27/2023]
Abstract
An oracle that correctly predicts the outcome of every particle physics experiment, the products of every possible chemical reaction or the function of every protein would revolutionize science and technology. However, scientists would not be entirely satisfied because they would want to comprehend how the oracle made these predictions. This is scientific understanding, one of the main aims of science. With the increase in the available computational power and advances in artificial intelligence, a natural question arises: how can advanced computational systems, and specifically artificial intelligence, contribute to new scientific understanding or gain it autonomously? Trying to answer this question, we adopted a definition of 'scientific understanding' from the philosophy of science that enabled us to overview the scattered literature on the topic and, combined with dozens of anecdotes from scientists, map out three dimensions of computer-assisted scientific understanding. For each dimension, we review the existing state of the art and discuss future developments. We hope that this Perspective will inspire and focus research directions in this multidisciplinary emerging field.
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Affiliation(s)
- Mario Krenn
- Max Planck Institute for the Science of Light (MPL), Erlangen, Germany
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario Canada
- Department of Computer Science, University of Toronto, Toronto, Ontario Canada
- Vector Institute for Artificial Intelligence, Toronto, Ontario Canada
| | - Robert Pollice
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario Canada
- Department of Computer Science, University of Toronto, Toronto, Ontario Canada
| | - Si Yue Guo
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario Canada
| | - Matteo Aldeghi
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario Canada
- Department of Computer Science, University of Toronto, Toronto, Ontario Canada
- Vector Institute for Artificial Intelligence, Toronto, Ontario Canada
| | - Alba Cervera-Lierta
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario Canada
- Department of Computer Science, University of Toronto, Toronto, Ontario Canada
| | - Pascal Friederich
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario Canada
- Department of Computer Science, University of Toronto, Toronto, Ontario Canada
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Gabriel dos Passos Gomes
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario Canada
- Department of Computer Science, University of Toronto, Toronto, Ontario Canada
| | - Florian Häse
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario Canada
- Department of Computer Science, University of Toronto, Toronto, Ontario Canada
- Vector Institute for Artificial Intelligence, Toronto, Ontario Canada
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA USA
| | - Adrian Jinich
- Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell Medical College, New York, USA
| | - AkshatKumar Nigam
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario Canada
- Department of Computer Science, University of Toronto, Toronto, Ontario Canada
| | - Zhenpeng Yao
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario Canada
- Center of Hydrogen Science, Shanghai Jiao Tong University, Shanghai, China
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
- Innovation Center for Future Materials, Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University, Shanghai, China
| | - Alán Aspuru-Guzik
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario Canada
- Department of Computer Science, University of Toronto, Toronto, Ontario Canada
- Vector Institute for Artificial Intelligence, Toronto, Ontario Canada
- Canadian Institute for Advanced Research (CIFAR) Lebovic Fellow, Toronto, Ontario Canada
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5
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Stark spectral line broadening modeling by machine learning algorithms. Neural Comput Appl 2022. [DOI: 10.1007/s00521-021-06763-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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6
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Paesani S, Bulmer JFF, Jones AE, Santagati R, Laing A. Scheme for Universal High-Dimensional Quantum Computation with Linear Optics. PHYSICAL REVIEW LETTERS 2021; 126:230504. [PMID: 34170150 DOI: 10.1103/physrevlett.126.230504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 03/19/2021] [Indexed: 06/13/2023]
Abstract
Photons are natural carriers of high-dimensional quantum information, and, in principle, can benefit from higher quantum information capacity and noise resilience. However, schemes to generate the resources required for high-dimensional quantum computing have so far been lacking in linear optics. Here, we show how to generate GHZ states in arbitrary dimensions and numbers of photons using linear optical circuits described by Fourier transform matrices. Combining our results with recent schemes for qudit Bell measurements, we show that universal linear optical quantum computing can be performed in arbitrary dimensions.
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Affiliation(s)
- Stefano Paesani
- Quantum Engineering Technology Labs, H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, University of Bristol, Bristol BS8 1FD, United Kingdom
- Center for Hybrid Quantum Networks (Hy-Q), Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark
| | - Jacob F F Bulmer
- Quantum Engineering Technology Labs, H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, University of Bristol, Bristol BS8 1FD, United Kingdom
| | - Alex E Jones
- Quantum Engineering Technology Labs, H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, University of Bristol, Bristol BS8 1FD, United Kingdom
| | - Raffaele Santagati
- Quantum Engineering Technology Labs, H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, University of Bristol, Bristol BS8 1FD, United Kingdom
- International Iberian Nanotechnology Laboratory (INL), Avenida Mestre José Veiga 4715-330 Braga, Portugal
| | - Anthony Laing
- Quantum Engineering Technology Labs, H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, University of Bristol, Bristol BS8 1FD, United Kingdom
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7
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Isoscattering strings of concatenating graphs and networks. Sci Rep 2021; 11:1575. [PMID: 33452312 PMCID: PMC7810996 DOI: 10.1038/s41598-020-80950-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 12/30/2020] [Indexed: 11/08/2022] Open
Abstract
We identify and investigate isoscattering strings of concatenating quantum graphs possessing n units and 2n infinite external leads. We give an insight into the principles of designing large graphs and networks for which the isoscattering properties are preserved for \documentclass[12pt]{minimal}
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\begin{document}$$n \rightarrow \infty $$\end{document}n→∞. The theoretical predictions are confirmed experimentally using \documentclass[12pt]{minimal}
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\begin{document}$$n=2$$\end{document}n=2 units, four-leads microwave networks. In an experimental and mathematical approach our work goes beyond prior results by demonstrating that using a trace function one can address the unsettled until now problem of whether scattering properties of open complex graphs and networks with many external leads are uniquely connected to their shapes. The application of the trace function reduces the number of required entries to the \documentclass[12pt]{minimal}
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\begin{document}$$2n \times 2n $$\end{document}2n×2n scattering matrices \documentclass[12pt]{minimal}
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\begin{document}$${\hat{S}}$$\end{document}S^ of the systems to 2n diagonal elements, while the old measures of isoscattering require all \documentclass[12pt]{minimal}
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\begin{document}$$(2n)^2$$\end{document}(2n)2 entries. The studied problem generalizes a famous question of Mark Kac “Can one hear the shape of a drum?”, originally posed in the case of isospectral dissipationless systems, to the case of infinite strings of open graphs and networks.
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8
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Gu X, Krenn M. Compact Greenberger—Horne—Zeilinger state generation via frequency combs and graph theory. FRONTIERS OF PHYSICS 2020; 15:61502. [DOI: 10.1007/s11467-020-1028-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Indexed: 09/02/2023]
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9
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Ławniczak M, van Tiggelen B, Sirko L. Experimental investigation of distributions of the off-diagonal elements of the scattering matrix and Wigner's K[over ̂] matrix for networks with broken time reversal invariance. Phys Rev E 2020; 102:052214. [PMID: 33327135 DOI: 10.1103/physreve.102.052214] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 11/03/2020] [Indexed: 11/07/2022]
Abstract
We present an extensive experimental study of the distributions of the real and imaginary parts of the off-diagonal elements of the scattering matrix S[over ̂] and the Wigner's reaction K[over ̂] matrix for open microwave networks with broken time (T) reversal invariance. Microwave Faraday circulators were applied in order to break T invariance. The experimental distributions of the real and imaginary parts of the off-diagonal entries of the scattering matrix S[over ̂] are compared with the theoretical predictions from the supersymmetry random matrix theory [A. Nock, S. Kumar, H.-J. Sommers, and T. Guhr, Ann. Phys. (NY) 342, 103 (2014)10.1016/j.aop.2013.11.006]. Furthermore, we show that the experimental results are in very good agreement with the recent predictions for the distributions of the real and imaginary parts of the off-diagonal elements of the Wigner's reaction K[over ̂] matrix obtained within the framework of the Gaussian unitary ensemble of random matrix theory [S. B. Fedeli and Y. V. Fyodorov, J. Phys. A: Math. Theor. 53, 165701 (2020)1751-811310.1088/1751-8121/ab73ab]. Both theories include losses as tunable parameters and are therefore well adapted to the experimental verification.
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Affiliation(s)
- Michał Ławniczak
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02-668 Warsaw, Poland
| | | | - Leszek Sirko
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02-668 Warsaw, Poland
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10
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Abstract
Quantum entanglement amounts to an extremely strong link between two distant particles, a link so strong that it eludes any classical description and so unsettling that Albert Einstein described it as “spooky action at a distance.” Today, entanglement is not only a subject of fundamental research, but also a workhorse of emerging quantum technologies. In our current work we experimentally demonstrate a completely different method of entanglement generation. Unlike many traditional methods, where entanglement arises due to conservation of a physical quantity, such as momentum, in our method it is rather a consequence of indistinguishability of several particle-generating processes. This approach, where each process effectively adds one dimension to the entangled state, allows for a high degree of customizability. We present an experimental demonstration of a general entanglement-generation framework, where the form of the entangled state is independent of the physical process used to produce the particles. It is the indistinguishability of multiple generation processes and the geometry of the setup that give rise to the entanglement. Such a framework, termed entanglement by path identity, exhibits a high degree of customizability. We employ one class of such geometries to build a modular source of photon pairs that are high-dimensionally entangled in their orbital angular momentum. We demonstrate the creation of three-dimensionally entangled states and show how to incrementally increase the dimensionality of entanglement. The generated states retain their quality even in higher dimensions. In addition, the design of our source allows for its generalization to various degrees of freedom and even for the implementation in integrated compact devices. The concept of entanglement by path identity itself is a general scheme and allows for construction of sources producing also customized states of multiple photons. We therefore expect that future quantum technologies and fundamental tests of nature in higher dimensions will benefit from this approach.
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Zhu P, Xue S, Zheng Q, Wu C, Yu X, Wang Y, Liu Y, Qiang X, Deng M, Wu J, Xu P. Reconfigurable multiphoton entangled states based on quantum photonic chips. OPTICS EXPRESS 2020; 28:26792-26806. [PMID: 32906947 DOI: 10.1364/oe.402383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 08/19/2020] [Indexed: 06/11/2023]
Abstract
Multipartite entanglement is one of the most prominent features of quantum mechanics and is the key ingredient in quantum information processing. Seeking for an advantageous way to generate it is of great value. Here we propose two different schemes to prepare multiphoton entangled states on a quantum photonic chip that are both based on the theory of entanglement on the graph. The first scheme is to construct graphs for multiphoton states by the network of spatially anti-bunching two-photon sources. The second one is to construct graphs by the linear beam-splitter network, which can generate W and Dicke states efficiently with simple structure. Both schemes can be scaled up in the photon number and can be reconfigured for different types of multiphoton states. This study supplies a systematic solution for the on-chip generation of multiphoton entangled states and will promote the practical development of multiphoton quantum technologies.
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Gao X, Erhard M, Zeilinger A, Krenn M. Computer-Inspired Concept for High-Dimensional Multipartite Quantum Gates. PHYSICAL REVIEW LETTERS 2020. [PMID: 32794870 DOI: 10.1038/s42254-020-0230-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
An open question in quantum optics is how to manipulate and control complex quantum states in an experimentally feasible way. Here we present concepts for transformations of high-dimensional multiphotonic quantum systems. The proposals rely on two new ideas: (i) a novel high-dimensional quantum nondemolition measurement, (ii) the encoding and decoding of the entire quantum transformation in an ancillary state for sharing the necessary quantum information between the involved parties. Many solutions can readily be performed in laboratories around the world and thereby we identify important pathways for experimental research in the near future. The concepts have been found using the computer algorithm melvin for designing computer-inspired quantum experiments. As opposed to the field of machine learning, here the human learns new scientific concepts by interpreting and analyzing the results presented by the machine. This demonstrates that computer algorithms can inspire new ideas in science, which has a widely unexplored potential that goes far beyond experimental quantum information science.
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Affiliation(s)
- Xiaoqin Gao
- Faculty of Physics, University of Vienna, Vienna, 1190, Austria
- Institute for Quantum Optics and Quantum Information (IQOQI) Vienna, Austrian Academy of Sciences, Vienna, 1190, Austria
- National Mobile Communications Research Laboratory and Quantum Information Research Center, Southeast University, Nanjing, 210096, China
| | - Manuel Erhard
- Faculty of Physics, University of Vienna, Vienna, 1190, Austria
- Institute for Quantum Optics and Quantum Information (IQOQI) Vienna, Austrian Academy of Sciences, Vienna, 1190, Austria
| | - Anton Zeilinger
- Faculty of Physics, University of Vienna, Vienna, 1190, Austria
- Institute for Quantum Optics and Quantum Information (IQOQI) Vienna, Austrian Academy of Sciences, Vienna, 1190, Austria
| | - Mario Krenn
- Faculty of Physics, University of Vienna, Vienna, 1190, Austria
- Institute for Quantum Optics and Quantum Information (IQOQI) Vienna, Austrian Academy of Sciences, Vienna, 1190, Austria
- Department of Chemistry and Computer Science, University of Toronto, Toronto, Ontario M5S 3G4, Canada
- Vector Institute for Artificial Intelligence, Toronto, Ontario M5G 1M1, Canada
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Gao X, Erhard M, Zeilinger A, Krenn M. Computer-Inspired Concept for High-Dimensional Multipartite Quantum Gates. PHYSICAL REVIEW LETTERS 2020; 125:050501. [PMID: 32794870 DOI: 10.1103/physrevlett.125.050501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 03/26/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
An open question in quantum optics is how to manipulate and control complex quantum states in an experimentally feasible way. Here we present concepts for transformations of high-dimensional multiphotonic quantum systems. The proposals rely on two new ideas: (i) a novel high-dimensional quantum nondemolition measurement, (ii) the encoding and decoding of the entire quantum transformation in an ancillary state for sharing the necessary quantum information between the involved parties. Many solutions can readily be performed in laboratories around the world and thereby we identify important pathways for experimental research in the near future. The concepts have been found using the computer algorithm melvin for designing computer-inspired quantum experiments. As opposed to the field of machine learning, here the human learns new scientific concepts by interpreting and analyzing the results presented by the machine. This demonstrates that computer algorithms can inspire new ideas in science, which has a widely unexplored potential that goes far beyond experimental quantum information science.
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Affiliation(s)
- Xiaoqin Gao
- Faculty of Physics, University of Vienna, Vienna, 1190, Austria
- Institute for Quantum Optics and Quantum Information (IQOQI) Vienna, Austrian Academy of Sciences, Vienna, 1190, Austria
- National Mobile Communications Research Laboratory and Quantum Information Research Center, Southeast University, Nanjing, 210096, China
| | - Manuel Erhard
- Faculty of Physics, University of Vienna, Vienna, 1190, Austria
- Institute for Quantum Optics and Quantum Information (IQOQI) Vienna, Austrian Academy of Sciences, Vienna, 1190, Austria
| | - Anton Zeilinger
- Faculty of Physics, University of Vienna, Vienna, 1190, Austria
- Institute for Quantum Optics and Quantum Information (IQOQI) Vienna, Austrian Academy of Sciences, Vienna, 1190, Austria
| | - Mario Krenn
- Faculty of Physics, University of Vienna, Vienna, 1190, Austria
- Institute for Quantum Optics and Quantum Information (IQOQI) Vienna, Austrian Academy of Sciences, Vienna, 1190, Austria
- Department of Chemistry and Computer Science, University of Toronto, Toronto, Ontario M5S 3G4, Canada
- Vector Institute for Artificial Intelligence, Toronto, Ontario M5G 1M1, Canada
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14
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Investigation of the diagonal elements of the Wigner's reaction matrix for networks with violated time reversal invariance. Sci Rep 2019; 9:5630. [PMID: 30948771 PMCID: PMC6449383 DOI: 10.1038/s41598-019-42123-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 03/25/2019] [Indexed: 11/11/2022] Open
Abstract
The distributions of the diagonal elements of the Wigner’s reaction \documentclass[12pt]{minimal}
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\begin{document}$$\hat{K}$$\end{document}Kˆ matrix for open systems with violated time reversal T invariance in the case of large absorption are for the first time experimentally studied. The Wigner’s reaction matrix links the properties of chaotic systems with the scattering processes in the asymptotic region. Microwave networks consisting of microwave circulators were used in the experiment to simulate quantum graphs with violated T invariance. The distributions of the diagonal elements of the reaction \documentclass[12pt]{minimal}
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\begin{document}$$\hat{K}$$\end{document}Kˆ matrix were experimentally evaluated by measuring of the two-port scattering matrix \documentclass[12pt]{minimal}
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\begin{document}$$\hat{S}$$\end{document}Sˆ. The violation of T invariance in the networks with large absorption was demonstrated by calculating the enhancement factor W of the matrix \documentclass[12pt]{minimal}
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\begin{document}$$\hat{S}$$\end{document}Sˆ. Our experimental results are in very good agreement with the analytic ones attained for the Gaussian unitary ensemble in the random matrix theory. The obtained results suggest that the distributions P(ʋ) and P(u) of the imaginary and the real parts of the diagonal elements of the Wigner’s reaction \documentclass[12pt]{minimal}
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\begin{document}$$\hat{K}$$\end{document}Kˆ matrix together with the enhancement factor W can be used as a powerful tool for identification of systems with violated T symmetry and quantification of their absorption.
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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.
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Erhard M, Fickler R, Krenn M, Zeilinger A. Twisted photons: new quantum perspectives in high dimensions. LIGHT, SCIENCE & APPLICATIONS 2018; 7:17146. [PMID: 30839541 PMCID: PMC6060046 DOI: 10.1038/lsa.2017.146] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/21/2017] [Accepted: 10/16/2017] [Indexed: 05/20/2023]
Abstract
Twisted photons can be used as alphabets to encode information beyond one bit per single photon. This ability offers great potential for quantum information tasks, as well as for the investigation of fundamental questions. In this review article, we give a brief overview of the theoretical differences between qubits and higher dimensional systems, qudits, in different quantum information scenarios. We then describe recent experimental developments in this field over the past three years. Finally, we summarize some important experimental and theoretical questions that might be beneficial to understand better in the near future.
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Affiliation(s)
- Manuel Erhard
- Vienna Center for Quantum Science & Technology (VCQ), Faculty of Physics, University of Vienna, Boltzmanngasse 5, Vienna 1090, Austria
- Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences, Boltzmanngasse 3, Vienna 1090, Austria
| | - Robert Fickler
- Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Mario Krenn
- Vienna Center for Quantum Science & Technology (VCQ), Faculty of Physics, University of Vienna, Boltzmanngasse 5, Vienna 1090, Austria
- Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences, Boltzmanngasse 3, Vienna 1090, Austria
| | - Anton Zeilinger
- Vienna Center for Quantum Science & Technology (VCQ), Faculty of Physics, University of Vienna, Boltzmanngasse 5, Vienna 1090, Austria
- Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences, Boltzmanngasse 3, Vienna 1090, Austria
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17
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Melnikov AA, Poulsen Nautrup H, Krenn M, Dunjko V, Tiersch M, Zeilinger A, Briegel HJ. Active learning machine learns to create new quantum experiments. Proc Natl Acad Sci U S A 2018; 115:1221-1226. [PMID: 29348200 PMCID: PMC5819408 DOI: 10.1073/pnas.1714936115] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
How useful can machine learning be in a quantum laboratory? Here we raise the question of the potential of intelligent machines in the context of scientific research. A major motivation for the present work is the unknown reachability of various entanglement classes in quantum experiments. We investigate this question by using the projective simulation model, a physics-oriented approach to artificial intelligence. In our approach, the projective simulation system is challenged to design complex photonic quantum experiments that produce high-dimensional entangled multiphoton states, which are of high interest in modern quantum experiments. The artificial intelligence system learns to create a variety of entangled states and improves the efficiency of their realization. In the process, the system autonomously (re)discovers experimental techniques which are only now becoming standard in modern quantum optical experiments-a trait which was not explicitly demanded from the system but emerged through the process of learning. Such features highlight the possibility that machines could have a significantly more creative role in future research.
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Affiliation(s)
- Alexey A Melnikov
- Institute for Theoretical Physics, University of Innsbruck, 6020 Innsbruck, Austria;
| | | | - Mario Krenn
- Vienna Center for Quantum Science and Technology, Faculty of Physics, University of Vienna, 1090 Vienna, Austria
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, 1090 Vienna, Austria
| | - Vedran Dunjko
- Institute for Theoretical Physics, University of Innsbruck, 6020 Innsbruck, Austria
| | - Markus Tiersch
- Institute for Theoretical Physics, University of Innsbruck, 6020 Innsbruck, Austria
| | - Anton Zeilinger
- Vienna Center for Quantum Science and Technology, Faculty of Physics, University of Vienna, 1090 Vienna, Austria;
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, 1090 Vienna, Austria
| | - Hans J Briegel
- Institute for Theoretical Physics, University of Innsbruck, 6020 Innsbruck, Austria
- Department of Philosophy, University of Konstanz, 78457 Konstanz, Germany
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