1
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Todorov Y, Dhillon S, Mangeney J. THz quantum gap: exploring potential approaches for generating and detecting non-classical states of THz light. NANOPHOTONICS 2024; 13:1681-1691. [PMID: 38681681 PMCID: PMC11052537 DOI: 10.1515/nanoph-2023-0757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 12/30/2023] [Indexed: 05/01/2024]
Abstract
Over the past few decades, THz technology has made considerable progress, evidenced by the performance of current THz sources and detectors, as well as the emergence of several THz applications. However, in the realm of quantum technologies, the THz spectral domain is still in its infancy, unlike neighboring spectral domains that have flourished in recent years. Notably, in the microwave domain, superconducting qubits currently serve as the core of quantum computers, while quantum cryptography protocols have been successfully demonstrated in the visible and telecommunications domains through satellite links. The THz domain has lagged behind in these impressive advancements. Today, the current gap in the THz domain clearly concerns quantum technologies. Nonetheless, the emergence of quantum technologies operating at THz frequencies will potentially have a significant impact. Indeed, THz radiation holds significant promise for wireless communications with ultimate security owing to its low sensitivity to atmospheric disturbances. Moreover, it has the potential to raise the operating temperature of solid-state qubits, effectively addressing existing scalability issues. In addition, THz radiation can manipulate the quantum states of molecules, which are recognized as new platforms for quantum computation and simulation with long range interactions. Finally, its ability to penetrate generally opaque materials or its resistance to Rayleigh scattering are very appealing features for quantum sensing. In this perspective, we will discuss potential approaches that offer exciting prospects for generating and detecting non-classical states of THz light, thereby opening doors to significant breakthroughs in THz quantum technologies.
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Affiliation(s)
- Yanko Todorov
- Laboratoire de Physique de l’Ecole normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Sukhdeep Dhillon
- Laboratoire de Physique de l’Ecole normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Juliette Mangeney
- Laboratoire de Physique de l’Ecole normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
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2
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De Filippis G, de Candia A, Di Bello G, Perroni CA, Cangemi LM, Nocera A, Sassetti M, Fazio R, Cataudella V. Signatures of Dissipation Driven Quantum Phase Transition in Rabi Model. PHYSICAL REVIEW LETTERS 2023; 130:210404. [PMID: 37295090 DOI: 10.1103/physrevlett.130.210404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 04/13/2023] [Indexed: 06/12/2023]
Abstract
By using the worldline Monte Carlo technique, matrix product state, and a variational approach à la Feynman, we investigate the equilibrium properties and relaxation features of the dissipative quantum Rabi model, where a two level system is coupled to a linear harmonic oscillator embedded in a viscous fluid. We show that, in the Ohmic regime, a Beretzinski-Kosterlitz-Thouless quantum phase transition occurs by varying the coupling strength between the two level system and the oscillator. This is a nonperturbative result, occurring even for extremely low dissipation magnitude. By using state-of-the-art theoretical methods, we unveil the features of the relaxation towards the thermodynamic equilibrium, pointing out the signatures of quantum phase transition both in the time and frequency domains. We prove that, for low and moderate values of the dissipation, the quantum phase transition occurs in the deep strong coupling regime. We propose to realize this model by coupling a flux qubit and a damped LC oscillator.
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Affiliation(s)
- G De Filippis
- SPIN-CNR and Dip. di Fisica E. Pancini-Università di Napoli Federico II-I-80126 Napoli, Italy
- INFN, Sezione di Napoli-Complesso Universitario di Monte S. Angelo-I-80126 Napoli, Italy
| | - A de Candia
- SPIN-CNR and Dip. di Fisica E. Pancini-Università di Napoli Federico II-I-80126 Napoli, Italy
- INFN, Sezione di Napoli-Complesso Universitario di Monte S. Angelo-I-80126 Napoli, Italy
| | - G Di Bello
- Dipartimento di Fisica Ettore Pancini-Università di Napoli Federico II-I-80126 Napoli, Italy
| | - C A Perroni
- SPIN-CNR and Dip. di Fisica E. Pancini-Università di Napoli Federico II-I-80126 Napoli, Italy
| | - L M Cangemi
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - A Nocera
- Department of Physics and Astronomy and Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z1
| | - M Sassetti
- Dipartimento di Fisica, Università di Genova, I-16146 Genova, Italy
- SPIN-CNR, I-16146 Genova, Italy
| | - R Fazio
- SPIN-CNR and Dip. di Fisica E. Pancini-Università di Napoli Federico II-I-80126 Napoli, Italy
- ICTP, Strada Costiera 11, I-34151 Trieste, Italy
- NEST, Istituto Nanoscienze-CNR, I-56126 Pisa, Italy
| | - V Cataudella
- SPIN-CNR and Dip. di Fisica E. Pancini-Università di Napoli Federico II-I-80126 Napoli, Italy
- INFN, Sezione di Napoli-Complesso Universitario di Monte S. Angelo-I-80126 Napoli, Italy
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3
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Koch J, Hunanyan GR, Ockenfels T, Rico E, Solano E, Weitz M. Quantum Rabi dynamics of trapped atoms far in the deep strong coupling regime. Nat Commun 2023; 14:954. [PMID: 36808135 PMCID: PMC9941496 DOI: 10.1038/s41467-023-36611-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 02/09/2023] [Indexed: 02/22/2023] Open
Abstract
The coupling of a two-level system with an electromagnetic field, whose fully quantized version is the quantum Rabi model, is among the central topics of quantum physics. When the coupling strength becomes large enough that the field mode frequency is reached, the deep strong coupling regime is approached, and excitations can be created from the vacuum. Here we demonstrate a periodic variant of the quantum Rabi model in which the two-level system is encoded in the Bloch band structure of cold rubidium atoms in optical potentials. With this method we achieve a Rabi coupling strength of 6.5 times the field mode frequency, which is far in the deep strong coupling regime, and observe a subcycle timescale raise in bosonic field mode excitations. In a measurement recorded in the basis of the coupling term of the quantum Rabi Hamiltonian, a freezing of dynamics is revealed for small frequency splittings of the two-level system, as expected when the coupling term dominates over all other energy scales, and a revival for larger splittings. Our work demonstrates a route to realize quantum-engineering applications in yet unexplored parameter regimes.
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Affiliation(s)
- Johannes Koch
- Institut für Angewandte Physik, Universität Bonn, Wegelerstr. 8, 53115, Bonn, Germany.
| | - Geram R. Hunanyan
- grid.10388.320000 0001 2240 3300Institut für Angewandte Physik, Universität Bonn, Wegelerstr. 8, 53115 Bonn, Germany
| | - Till Ockenfels
- grid.10388.320000 0001 2240 3300Institut für Angewandte Physik, Universität Bonn, Wegelerstr. 8, 53115 Bonn, Germany
| | - Enrique Rico
- grid.11480.3c0000000121671098EHU Quantum Center, University of the Basque Country UPV/EHU, P.O. Box 644, 48080 Bilbao, Spain ,grid.11480.3c0000000121671098Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain ,grid.424810.b0000 0004 0467 2314IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, 48009 Bilbao, Spain
| | - Enrique Solano
- grid.11480.3c0000000121671098Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain ,grid.424810.b0000 0004 0467 2314IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, 48009 Bilbao, Spain ,Kipu Quantum, Greifswalder Straße 226, 10405 Berlin, Germany ,grid.39436.3b0000 0001 2323 5732International Center of Quantum Artificial Intelligence for Science and Technology (QuArtist) and Department of Physics, Shanghai University, 200444 Shanghai, China
| | - Martin Weitz
- Institut für Angewandte Physik, Universität Bonn, Wegelerstr. 8, 53115, Bonn, Germany.
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4
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Grimaudo R, de Castro ASM, Messina A, Solano E, Valenti D. Quantum Phase Transitions for an Integrable Quantum Rabi-like Model with Two Interacting Qubits. PHYSICAL REVIEW LETTERS 2023; 130:043602. [PMID: 36763445 DOI: 10.1103/physrevlett.130.043602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/13/2022] [Accepted: 12/22/2022] [Indexed: 06/18/2023]
Abstract
A two-interacting-qubit quantum Rabi-like model with vanishing transverse fields on the qubit pair is studied. Independently of the coupling regime, this model can be exactly and unitarily reduced to two independent single-spin quantum Rabi models, where the spin-spin coupling plays the role of the transverse field. This transformation and the analytical treatment of the single-spin quantum Rabi model provide the key to prove the integrability of our model. The existence of different first-order quantum phase transitions, characterized by discontinuous two-spin magnetization, mean photon number, and concurrence, is brought to light.
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Affiliation(s)
- R Grimaudo
- Department of Physics and Chemistry "Emilio Segrè", University of Palermo, viale delle Scienze, Building 18, I-90128, Palermo, Italy
| | - A S Magalhães de Castro
- Universidade Estadual de Ponta Grossa, Departamento de Física, CEP 84030-900, Ponta Grossa, Paraná state, Brazil
| | - A Messina
- Department of Mathematics and Informatics, University of Palermo, Via Archirafi 34, I-90123 Palermo, Italy
| | - E Solano
- International Center of Quantum Artificial Intelligence for Science and Technology (QuArtist) and Physics Department, Shanghai University, 200444 Shanghai, China
- IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, 48009 Bilbao, Spain
- Kipu Quantum, Greifswalderstrasse 226, 10405 Berlin, Germany
| | - D Valenti
- Department of Physics and Chemistry "Emilio Segrè", University of Palermo, viale delle Scienze, Building 18, I-90128, Palermo, Italy
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5
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Grimaudo R, Valenti D, Sergi A, Messina A. Superradiant Quantum Phase Transition for an Exactly Solvable Two-Qubit Spin-Boson Model. ENTROPY (BASEL, SWITZERLAND) 2023; 25:e25020187. [PMID: 36832554 PMCID: PMC9956034 DOI: 10.3390/e25020187] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/12/2023] [Accepted: 01/16/2023] [Indexed: 06/01/2023]
Abstract
A spin-boson-like model with two interacting qubits is analysed. The model turns out to be exactly solvable since it is characterized by the exchange symmetry between the two spins. The explicit expressions of eigenstates and eigenenergies make it possible to analytically unveil the occurrence of first-order quantum phase transitions. The latter are physically relevant since they are characterized by abrupt changes in the two-spin subsystem concurrence, in the net spin magnetization and in the mean photon number.
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Affiliation(s)
- Roberto Grimaudo
- Dipartimento di Fisica e Chimica “Emilio Segrè”, Group of Interdisciplinary Theoretical Physics, Università degli Studi di Palermo, Viale delle Scienze Ed. 18, 90128 Palermo, Italy
| | - Davide Valenti
- Dipartimento di Fisica e Chimica “Emilio Segrè”, Group of Interdisciplinary Theoretical Physics, Università degli Studi di Palermo, Viale delle Scienze Ed. 18, 90128 Palermo, Italy
| | - Alessandro Sergi
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
- Institute of Systems Science, Durban University of Technology, P.O. Box 1334, Durban 4000, South Africa
| | - Antonino Messina
- Dipartimento di Matematica ed Informatica, Università degli Studi di Palermo, Via Archirafi 34, 90123 Palermo, Italy
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6
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Pérez-González B, Gómez-León Á, Platero G. Topology detection in cavity QED. Phys Chem Chem Phys 2022; 24:15860-15870. [PMID: 35758058 DOI: 10.1039/d2cp01806c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We explore the physics of topological lattice models immersed in c-QED architectures for arbitrary coupling strength with the photon field. We propose the use of the cavity transmission as a topological marker and study its behaviour. For this, we develop an approach combining the input-output formalism with a Mean-Field plus fluctuations description of the setup. We illustrate our results with the specific case of a fermionic Su-Schrieffer-Heeger (SSH) chain coupled to a single-mode cavity. Our findings confirm that the cavity can indeed act as a quantum sensor for topological phases, where the initial state preparation plays a crucial role. Additionally, we discuss the persistence of topological features when the coupling strength increases, in terms of an effective Hamiltonian, and calculate the entanglement entropy. Our approach can be applied to other fermionic systems, opening a route to the characterization of their topological properties in terms of experimental observables.
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Affiliation(s)
- Beatriz Pérez-González
- Instituto de Ciencia de Materiales de Madrid, ICMM-CSIC, Calle Sor Juana Inés de la Cruz, n°3, 28049 Madrid, Spain.
| | - Álvaro Gómez-León
- Instituto de Física Fundamental, IFF-CSIC, Calle Serrano 113b, 28006 Madrid, Spain
| | - Gloria Platero
- Instituto de Ciencia de Materiales de Madrid, ICMM-CSIC, Calle Sor Juana Inés de la Cruz, n°3, 28049 Madrid, Spain.
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7
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Bin Q, Wu Y, Lü XY. Parity-Symmetry-Protected Multiphoton Bundle Emission. PHYSICAL REVIEW LETTERS 2021; 127:073602. [PMID: 34459658 DOI: 10.1103/physrevlett.127.073602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Accepted: 07/09/2021] [Indexed: 06/13/2023]
Abstract
We demonstrate symmetry protected multiphoton bundle emission in the cavity QED system under the ultrastrong coupling regime. Our proposal only enables the super-Rabi oscillations with periodic generation of even correlated photons in the cavity, which is realized by combining the laser driven flip of qubit and the symmetry conserved transitions induced by Rabi interaction with parity symmetry. Combined with dissipation, only 2n-photon bundle emissions are allowed, due to the almost perfect suppression of bundle emissions with odd correlated photons. Meanwhile, the corresponding purities are significantly enhanced by the parity symmetry. This work extends multiphoton bundle emission to the ultrastrong coupling regime, and offers the prospect of exploring symmetry-protected multiphoton physics.
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Affiliation(s)
- Qian Bin
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Ying Wu
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Xin-You Lü
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
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8
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Peng J, Zheng J, Yu J, Tang P, Barrios GA, Zhong J, Solano E, Albarrán-Arriagada F, Lamata L. One-Photon Solutions to the Multiqubit Multimode Quantum Rabi Model for Fast W-State Generation. PHYSICAL REVIEW LETTERS 2021; 127:043604. [PMID: 34355937 DOI: 10.1103/physrevlett.127.043604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
General solutions to the quantum Rabi model involve subspaces with an unbounded number of photons. However, for the multiqubit multimode case, we find special solutions with at most one photon for an arbitrary number of qubits and photon modes. Such solutions exist for arbitrary single qubit-photon coupling strength with constant eigenenergy, while still being qubit-photon entangled states. Taking advantage of their peculiarities and the reach of the ultrastrong coupling regime, we propose an adiabatic scheme for the fast and deterministic generation of a two-qubit Bell state and arbitrary single-photon multimode W states with nonadiabatic error less than 1%. Finally, we propose a superconducting circuit design to catch and release the W states, and shows the experimental feasibility of the multimode multiqubit quantum Rabi model.
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Affiliation(s)
- Jie Peng
- Hunan Key Laboratory for Micro-Nano Energy Materials and Devices and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Juncong Zheng
- Hunan Key Laboratory for Micro-Nano Energy Materials and Devices and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Jing Yu
- International Center of Quantum Artificial Intelligence for Science and Technology (QuArtist) and Physics Department, Shanghai University, 200444 Shanghai, China
| | - Pinghua Tang
- Hunan Key Laboratory for Micro-Nano Energy Materials and Devices and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - G Alvarado Barrios
- International Center of Quantum Artificial Intelligence for Science and Technology (QuArtist) and Physics Department, Shanghai University, 200444 Shanghai, China
| | - Jianxin Zhong
- Hunan Key Laboratory for Micro-Nano Energy Materials and Devices and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Enrique Solano
- International Center of Quantum Artificial Intelligence for Science and Technology (QuArtist) and Physics Department, Shanghai University, 200444 Shanghai, China
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain
- IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, 48009 Bilbao, Spain
- Kipu Quantum, Kurwenalstrasse 1, 80804 Munich, Germany
| | - F Albarrán-Arriagada
- International Center of Quantum Artificial Intelligence for Science and Technology (QuArtist) and Physics Department, Shanghai University, 200444 Shanghai, China
| | - Lucas Lamata
- Departamento de Física Atómica, Molecular y Nuclear, Universidad de Sevilla, 41080 Sevilla, Spain
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9
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Thomas PA, Tan WJ, Fernandez HA, Barnes WL. A New Signature for Strong Light-Matter Coupling Using Spectroscopic Ellipsometry. NANO LETTERS 2020; 20:6412-6419. [PMID: 32709208 PMCID: PMC7608940 DOI: 10.1021/acs.nanolett.0c01963] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/23/2020] [Indexed: 05/25/2023]
Abstract
Light-matter interactions can occur when an ensemble of molecular resonators is placed in a confined electromagnetic field. In the strong coupling regime the rapid exchange of energy between the molecules and the electromagnetic field results in the emergence of hybrid light-matter states called polaritons. Multiple criteria exist to define the strong coupling regime, usually by comparing the splitting of the polariton bands with the line widths of the uncoupled modes. Here, we highlight the limitations of these criteria and study strong coupling using spectroscopic ellipsometry, a commonly used optical characterization technique. We identify a new signature of strong coupling in ellipsometric phase spectra. The combination of ellipsometric amplitude and phase spectra yields a distinct topological feature that we suggest could serve as a new criterion for strong coupling. Our results introduce the idea of ellipsometric topology and could provide further insight into the transition from the weak to strong coupling regime.
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10
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Mueller NS, Okamura Y, Vieira BGM, Juergensen S, Lange H, Barros EB, Schulz F, Reich S. Deep strong light–matter coupling in plasmonic nanoparticle crystals. Nature 2020; 583:780-784. [DOI: 10.1038/s41586-020-2508-1] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 04/21/2020] [Indexed: 11/09/2022]
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11
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Zhou JY, Zhou YH, Yin XL, Huang JF, Liao JQ. Quantum entanglement maintained by virtual excitations in an ultrastrongly-coupled-oscillator system. Sci Rep 2020; 10:12557. [PMID: 32724074 PMCID: PMC7387496 DOI: 10.1038/s41598-020-68309-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 05/22/2020] [Indexed: 11/09/2022] Open
Abstract
We study the effect of quantum entanglement maintained by virtual excitations in an ultrastrongly-coupled harmonic-oscillator system. Here, the quantum entanglement is caused by the counterrotating interaction terms and hence it is maintained by the virtual excitations. We obtain the analytical expression for the ground state of the system and analyze the relationship between the average excitation numbers and the ground-state entanglement. We also study the entanglement dynamics between the two oscillators in both the closed- and open-system cases. In the latter case, the quantum master equation is microscopically derived in the normal-mode representation of the coupled-oscillator system. This work will open a route to the study of quantum information processing and quantum physics based on virtual excitations.
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Affiliation(s)
- Jian-Yong Zhou
- Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, 410081, China.,Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan Normal University, Changsha, 410081, China.,Key Laboratory for Matter Microstructure and Function of Hunan Province, Hunan Normal University, Changsha, 410081, China
| | - Yue-Hui Zhou
- Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, 410081, China.,Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan Normal University, Changsha, 410081, China.,Key Laboratory for Matter Microstructure and Function of Hunan Province, Hunan Normal University, Changsha, 410081, China
| | - Xian-Li Yin
- Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, 410081, China.,Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan Normal University, Changsha, 410081, China.,Key Laboratory for Matter Microstructure and Function of Hunan Province, Hunan Normal University, Changsha, 410081, China
| | - Jin-Feng Huang
- Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, 410081, China. .,Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan Normal University, Changsha, 410081, China. .,Key Laboratory for Matter Microstructure and Function of Hunan Province, Hunan Normal University, Changsha, 410081, China.
| | - Jie-Qiao Liao
- Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, 410081, China. .,Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan Normal University, Changsha, 410081, China. .,Key Laboratory for Matter Microstructure and Function of Hunan Province, Hunan Normal University, Changsha, 410081, China.
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12
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Cui WX, Xing Y, Qi L, Han X, Liu S, Zhang S, Wang HF. Quantum walks in periodically kicked circuit QED lattice. OPTICS EXPRESS 2020; 28:13532-13541. [PMID: 32403825 DOI: 10.1364/oe.390352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 04/09/2020] [Indexed: 06/11/2023]
Abstract
We investigate the quantum walks of a single particle in a one-dimensional periodically kicked circuit quantum electrodynamics lattice. It is found that the dynamic process of the quantum walker is affected by the strength of incommensurate potentials and the driven periods of the system. We calculate the mean square displacement to illustrate the dynamic properties of the quantum walks, which shows that the localized process of the quantum walker presents the zero power-law index distribution. By calculating the mean information entropy, we find that the next-nearest-neighbor interactions have a remarkable deviation effects on the quantum walks and make a more stricter parameter condition for the localization of the quantum walker. Moreover, assisted by the lattice-based cavity input-output process, the localized features of circuit quantum electrodynamics lattice can be observed by measuring the average photon number of the cavity field in the steady state.
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13
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Realization of efficient quantum gates with a superconducting qubit-qutrit circuit. Sci Rep 2019; 9:13389. [PMID: 31527726 PMCID: PMC6746868 DOI: 10.1038/s41598-019-49657-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 08/08/2019] [Indexed: 11/25/2022] Open
Abstract
Building a quantum computer is a daunting challenge since it requires good control but also good isolation from the environment to minimize decoherence. It is therefore important to realize quantum gates efficiently, using as few operations as possible, to reduce the amount of required control and operation time and thus improve the quantum state coherence. Here we propose a superconducting circuit for implementing a tunable system consisting of a qutrit coupled to two qubits. This system can efficiently accomplish various quantum information tasks, including generation of entanglement of the two qubits and conditional three-qubit quantum gates, such as the Toffoli and Fredkin gates. Furthermore, the system realizes a conditional geometric gate which may be used for holonomic (non-adiabatic) quantum computing. The efficiency, robustness and universality of the presented circuit makes it a promising candidate to serve as a building block for larger networks capable of performing involved quantum computational tasks.
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14
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Ultrastrong coupling probed by Coherent Population Transfer. Sci Rep 2019; 9:9249. [PMID: 31239455 PMCID: PMC6592926 DOI: 10.1038/s41598-019-45187-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 05/30/2019] [Indexed: 11/08/2022] Open
Abstract
Light-matter interaction, and the understanding of the fundamental physics behind, is the scenario of emerging quantum technologies. Solid state devices allow the exploration of new regimes where ultrastrong coupling strengths are comparable to subsystem energies, and new exotic phenomena like quantum phase transitions and ground-state entanglement occur. While experiments so far provided only spectroscopic evidence of ultrastrong coupling, we propose a new dynamical protocol for detecting virtual photon pairs in the dressed eigenstates. This is the fingerprint of the violated conservation of the number of excitations, which heralds the symmetry broken by ultrastrong coupling. We show that in flux-based superconducting architectures this photon production channel can be coherently amplified by Stimulated Raman Adiabatic Passage, providing a unique tool for an unambiguous dynamical detection of ultrastrong coupling in present day hardware. This protocol could be a benchmark for control of the dynamics of ultrastrong coupling architectures, in view of applications to quantum information and microwave quantum photonics.
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15
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Wang G, Xiao R, Shen HZ, Sun C, Xue K. Simulating Anisotropic quantum Rabi model via frequency modulation. Sci Rep 2019; 9:4569. [PMID: 30872697 PMCID: PMC6418198 DOI: 10.1038/s41598-019-40899-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 02/25/2019] [Indexed: 11/09/2022] Open
Abstract
Anisotropic quantum Rabi model is a generalization of quantum Rabi model, which allows its rotating and counter-rotating terms to have two different coupling constants. It provides us with a fundamental model to understand various physical features concerning quantum optics, solid-state physics, and mesoscopic physics. In this paper, we propose an experimental feasible scheme to implement anisotropic quantum Rabi model in a circuit quantum electrodynamics system via periodic frequency modulation. An effective Hamiltonian describing the tunable anisotropic quantum Rabi model can be derived from a qubit-resonator coupling system modulated by two periodic driving fields. All effective parameters of the simulated system can be adjusted by tuning the initial phases, the frequencies and the amplitudes of the driving fields. We show that the periodic driving is able to drive a coupled system in dispersive regime to ultrastrong coupling regime, and even deep-strong coupling regime. The derived effective Hamiltonian allows us to obtain pure rotating term and counter-rotating term. Numerical simulation shows that such effective Hamiltonian is valid in ultrastrong coupling regime, and stronger coupling regime. Moreover, our scheme can be generalized to the multi-qubit case. We also give some applications of the simulated system to the Schrödinger cat states and quantum gate generalization. The presented proposal will pave a way to further study the stronger anisotropic Rabi model whose coupling strength is far away from ultrastrong coupling and deep-strong coupling regimes in quantum optics.
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Affiliation(s)
- Gangcheng Wang
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China.
| | - Ruoqi Xiao
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China
| | - H Z Shen
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China.
| | - Chunfang Sun
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China
| | - Kang Xue
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China.
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16
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Parity-Assisted Generation of Nonclassical States of Light in Circuit Quantum Electrodynamics. Symmetry (Basel) 2019. [DOI: 10.3390/sym11030372] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
We propose a method to generate nonclassical states of light in multimode microwave cavities. Our approach considers two-photon processes that take place in a system composed of N extended cavities and an ultrastrongly coupled light–matter system. Under specific resonance conditions, our method generates, in a deterministic manner, product states of uncorrelated photon pairs, Bell states, and W states in different modes on the extended cavities. Furthermore, the numerical simulations show that the generation scheme exhibits a collective effect which decreases the generation time in the same proportion as the number of extended cavity increases. Moreover, the entanglement encoded in the photonic states can be transferred towards ancillary two-level systems to generate genuine multipartite entanglement. Finally, we discuss the feasibility of our proposal in circuit quantum electrodynamics. This proposal could be of interest in the context of quantum random number generator, due to the quadratic scaling of the output state.
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17
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Liu X, Liao Q, Fang G, Liu S. Dynamic generation of multi-qubit entanglement in the ultrastrong-coupling regime. Sci Rep 2019; 9:2919. [PMID: 30814541 PMCID: PMC6393681 DOI: 10.1038/s41598-019-39265-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 01/16/2019] [Indexed: 11/09/2022] Open
Abstract
We propose a dynamic evolution protocol for generating multi-qubit GHZ states in the ultrastrong-coupling regime of circuit QED. By varying the time length of sequences, the protocol works for any coupling strength g/ωr ≥ 0.25. The time for generating the GHZ states in our protocol can be in the subnanoseconds. By taking into account realistic parameters of circuit QED, the degeneracy of fidelity due to decoherence can be as low as 0.02%.
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Affiliation(s)
- Xin Liu
- School of Physics and Technology, University of Jinan, Jinan, 250022, People's Republic of China.
| | - Qinghong Liao
- Department of Electronic Information Engineering, Nanchang University, Nanchang, 330031, People's Republic of China
| | - Guangyu Fang
- Department of Physics, Harbin Institute of Technology, Harbin, 150001, People's Republic of China
| | - Shutian Liu
- Department of Physics, Harbin Institute of Technology, Harbin, 150001, People's Republic of China
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18
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Li J, Wang G, Xiao R, Sun C, Wu C, Xue K. Multi-qubit Quantum Rabi Model and Multi-partite Entangled States in a Circuit QED System. Sci Rep 2019; 9:1380. [PMID: 30718592 PMCID: PMC6362268 DOI: 10.1038/s41598-018-35751-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/10/2018] [Indexed: 11/24/2022] Open
Abstract
Multi-qubit quantum Rabi model, which is a fundamental model describing light-matter interaction, plays an important role in various physical systems. In this paper, we propose a theoretical method to simulate multi-qubit quantum Rabi model in a circuit quantum electrodynamics system. By means of external transversal and longitudinal driving fields, an effective Hamiltonian describing the multi-qubit quantum Rabi model is derived. The effective frequency of the resonator and the effective splitting of the qubits depend on the external driving fields. By adjusting the frequencies and the amplitudes of the driving fields, the stronger coupling regimes could be reached. The numerical simulation shows that our proposal works well in a wide range of parameter space. Moreover, our scheme can be utilized to generate two-qubit gate, Schrödinger states, and multi-qubit GHZ states. The maximum displacement of the Schrödinger cat states can be enhanced by increasing the number of the qubits and the relative coupling strength. It should be mention that we can obtain high fidelity Schrödinger cat states and multi-qubit GHZ states even the system suffering dissipation. The presented proposal may open a way to study the stronger coupling regimes whose coupling strength is far away from ultrastrong coupling regimes.
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Affiliation(s)
- Jialun Li
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China
| | - Gangcheng Wang
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China.
| | - Ruoqi Xiao
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China
| | - Chunfang Sun
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China.
| | - Chunfeng Wu
- Science and Mathematics, and Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore, 487372, Singapore
| | - Kang Xue
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China.
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19
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Gauge ambiguities imply Jaynes-Cummings physics remains valid in ultrastrong coupling QED. Nat Commun 2019; 10:499. [PMID: 30700701 PMCID: PMC6354024 DOI: 10.1038/s41467-018-08101-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 12/14/2018] [Indexed: 11/18/2022] Open
Abstract
Ultrastrong-coupling between two-level systems and radiation is important for both fundamental and applied quantum electrodynamics (QED). Such regimes are identified by the breakdown of the rotating-wave approximation, which applied to the quantum Rabi model (QRM) yields the apparently less fundamental Jaynes-Cummings model (JCM). We show that when truncating the material system to two levels, each gauge gives a different description whose predictions vary significantly for ultrastrong-coupling. QRMs are obtained through specific gauge choices, but so too is a JCM without needing the rotating-wave approximation. Analysing a circuit QED setup, we find that this JCM provides more accurate predictions than the QRM for the ground state, and often for the first excited state as well. Thus, Jaynes-Cummings physics is not restricted to light-matter coupling below the ultrastrong limit. Among the many implications is that the system’s ground state is not necessarily highly entangled, which is usually considered a hallmark of ultrastrong-coupling. Modelling of light-matter interaction in the ultrastrong coupling regime is still debated. Here, the authors study the consequences of gauge freedom for a two-level system in a single-mode cavity, showing that the Jaynes-Cummings model can outperform the quantum Rabi model even for ultrastrong coupling.
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20
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Dareau A, Meng Y, Schneeweiss P, Rauschenbeutel A. Observation of Ultrastrong Spin-Motion Coupling for Cold Atoms in Optical Microtraps. PHYSICAL REVIEW LETTERS 2018; 121:253603. [PMID: 30608799 DOI: 10.1103/physrevlett.121.253603] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 11/18/2018] [Indexed: 06/09/2023]
Abstract
We realize a mechanical analogue of the Dicke model, achieved by coupling the spin of individual neutral atoms to their quantized motion in an optical trapping potential. The atomic spin states play the role of the electronic states of the atomic ensemble considered in the Dicke model, and the in-trap motional states of the atoms correspond to the states of the electromagnetic field mode. The coupling between spin and motion is induced by an inherent polarization gradient of the trapping light fields, which leads to a spatially varying vector light shift. We experimentally show that our system reaches the ultrastrong coupling regime; i.e., we obtain a coupling strength that is a significant fraction of the trap frequency. Moreover, with the help of an additional light field, we demonstrate the in situ tuning of the coupling strength. Beyond its fundamental interest, the demonstrated one-to-one mapping between the physics of optically trapped cold atoms and the Dicke model paves the way for implementing protocols and applications that exploit extreme coupling strengths.
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Affiliation(s)
- A Dareau
- Vienna Center for Quantum Science and Technology, TU Wien-Atominstitut, Stadionallee 2, 1020 Vienna, Austria
| | - Y Meng
- Vienna Center for Quantum Science and Technology, TU Wien-Atominstitut, Stadionallee 2, 1020 Vienna, Austria
| | - P Schneeweiss
- Vienna Center for Quantum Science and Technology, TU Wien-Atominstitut, Stadionallee 2, 1020 Vienna, Austria
| | - A Rauschenbeutel
- Vienna Center for Quantum Science and Technology, TU Wien-Atominstitut, Stadionallee 2, 1020 Vienna, Austria
- Department of Physics, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
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21
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Quantum Mechanical Engine for the Quantum Rabi Model. ENTROPY 2018; 20:e20100767. [PMID: 33265855 PMCID: PMC7512331 DOI: 10.3390/e20100767] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 09/28/2018] [Accepted: 10/05/2018] [Indexed: 11/17/2022]
Abstract
We consider a purely mechanical quantum cycle comprised of adiabatic and isoenergetic processes. In the latter, the system interacts with an energy bath keeping constant the expectation value of the Hamiltonian. In this work, we study the performance of the quantum cycle for a system described by the quantum Rabi model for the case of controlling the coupling strength parameter, the resonator frequency, and the two-level system frequency. For the cases of controlling either the coupling strength parameter or the resonator frequency, we find that it is possible to closely approach to maximal unit efficiency when the parameter is sufficiently increased in the first adiabatic stage. In addition, for the first two cases the maximal work extracted is obtained at parameter values corresponding to high efficiency, which constitutes an improvement over current proposals of this cycle.
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22
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Marković D, Jezouin S, Ficheux Q, Fedortchenko S, Felicetti S, Coudreau T, Milman P, Leghtas Z, Huard B. Demonstration of an Effective Ultrastrong Coupling between Two Oscillators. PHYSICAL REVIEW LETTERS 2018; 121:040505. [PMID: 30095939 DOI: 10.1103/physrevlett.121.040505] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Indexed: 06/08/2023]
Abstract
When the coupling rate between two quantum systems becomes as large as their characteristic frequencies, it induces dramatic effects on their dynamics and even on the nature of their ground state. The case of a qubit coupled to a harmonic oscillator in this ultrastrong coupling regime has been investigated theoretically and experimentally. Here, we explore the case of two harmonic oscillators in the ultrastrong coupling regime. Probing the properties of their ground state remains out of reach in natural implementations. Therefore, we have realized an analog quantum simulation of this coupled system by dual frequency pumping a nonlinear superconducting circuit. The pump amplitudes directly tune the effective coupling rate. We observe spectroscopic signature of a mode hybridization that is characteristic of the ultrastrong coupling. We experimentally demonstrate a key property of the ground state of this simulated ultrastrong coupling between modes by observing simultaneous single- and two-mode squeezing of the radiated field below vacuum fluctuations.
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Affiliation(s)
- D Marković
- Département de physique de l'ENS, Laboratoire Pierre Aigrain, École normale supérieure, PSL Research University, Université Paris Diderot, Sorbonne Paris Cité, Sorbonne Universités, UPMC University Paris 06, CNRS, 75005 Paris, France
| | - S Jezouin
- Département de physique de l'ENS, Laboratoire Pierre Aigrain, École normale supérieure, PSL Research University, Université Paris Diderot, Sorbonne Paris Cité, Sorbonne Universités, UPMC University Paris 06, CNRS, 75005 Paris, France
| | - Q Ficheux
- Département de physique de l'ENS, Laboratoire Pierre Aigrain, École normale supérieure, PSL Research University, Université Paris Diderot, Sorbonne Paris Cité, Sorbonne Universités, UPMC University Paris 06, CNRS, 75005 Paris, France
- Université Lyon, ENS de Lyon, Université Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, F-69342 Lyon, France
| | - S Fedortchenko
- Laboratoire Matériaux et Phénomènes Quantiques, Sorbonne Paris Cité, Université Paris Diderot, CNRS UMR 7162, 75013 Paris, France
| | - S Felicetti
- Laboratoire Matériaux et Phénomènes Quantiques, Sorbonne Paris Cité, Université Paris Diderot, CNRS UMR 7162, 75013 Paris, France
| | - T Coudreau
- Laboratoire Matériaux et Phénomènes Quantiques, Sorbonne Paris Cité, Université Paris Diderot, CNRS UMR 7162, 75013 Paris, France
| | - P Milman
- Laboratoire Matériaux et Phénomènes Quantiques, Sorbonne Paris Cité, Université Paris Diderot, CNRS UMR 7162, 75013 Paris, France
| | - Z Leghtas
- Département de physique de l'ENS, Laboratoire Pierre Aigrain, École normale supérieure, PSL Research University, Université Paris Diderot, Sorbonne Paris Cité, Sorbonne Universités, UPMC University Paris 06, CNRS, 75005 Paris, France
- Centre Automatique et Systèmes, Mines ParisTech, PSL Research University, 60 Boulevard Saint-Michel, 75272 Paris Cedex 6, France
- QUANTIC Team, INRIA de Paris, 2 Rue Simone Iff, 75012 Paris, France
| | - B Huard
- Département de physique de l'ENS, Laboratoire Pierre Aigrain, École normale supérieure, PSL Research University, Université Paris Diderot, Sorbonne Paris Cité, Sorbonne Universités, UPMC University Paris 06, CNRS, 75005 Paris, France
- Université Lyon, ENS de Lyon, Université Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, F-69342 Lyon, France
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23
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Yoshihara F, Fuse T, Ao Z, Ashhab S, Kakuyanagi K, Saito S, Aoki T, Koshino K, Semba K. Inversion of Qubit Energy Levels in Qubit-Oscillator Circuits in the Deep-Strong-Coupling Regime. PHYSICAL REVIEW LETTERS 2018; 120:183601. [PMID: 29775324 DOI: 10.1103/physrevlett.120.183601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Indexed: 06/08/2023]
Abstract
We report on experimentally measured light shifts of superconducting flux qubits deep-strongly coupled to LC oscillators, where the coupling constants are comparable to the qubit and oscillator resonance frequencies. By using two-tone spectroscopy, the energies of the six lowest levels of each circuit are determined. We find huge Lamb shifts that exceed 90% of the bare qubit frequencies and inversions of the qubits' ground and excited states when there are a finite number of photons in the oscillator. Our experimental results agree with theoretical predictions based on the quantum Rabi model.
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Affiliation(s)
- F Yoshihara
- Advanced ICT Institute, National Institute of Information and Communications Technology, 4-2-1, Nukuikitamachi, Koganei, Tokyo 184-8795, Japan
| | - T Fuse
- Advanced ICT Institute, National Institute of Information and Communications Technology, 4-2-1, Nukuikitamachi, Koganei, Tokyo 184-8795, Japan
| | - Z Ao
- Department of Applied Physics, Waseda University, 3-4-1, Ookubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - S Ashhab
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar
| | - K Kakuyanagi
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - S Saito
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - T Aoki
- Department of Applied Physics, Waseda University, 3-4-1, Ookubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - K Koshino
- College of Liberal Arts and Sciences, Tokyo Medical and Dental University, 2-8-30, Kounodai, Ichikawa, Chiba 272-0827, Japan
| | - K Semba
- Advanced ICT Institute, National Institute of Information and Communications Technology, 4-2-1, Nukuikitamachi, Koganei, Tokyo 184-8795, Japan
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24
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Leroux C, Govia LCG, Clerk AA. Enhancing Cavity Quantum Electrodynamics via Antisqueezing: Synthetic Ultrastrong Coupling. PHYSICAL REVIEW LETTERS 2018; 120:093602. [PMID: 29547301 DOI: 10.1103/physrevlett.120.093602] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 12/01/2017] [Indexed: 06/08/2023]
Abstract
We present and analyze a method where parametric (two-photon) driving of a cavity is used to exponentially enhance the light-matter coupling in a generic cavity QED setup, with time-dependent control. Our method allows one to enhance weak-coupling systems, such that they enter the strong coupling regime (where the coupling exceeds dissipative rates) and even the ultrastrong coupling regime (where the coupling is comparable to the cavity frequency). As an example, we show how the scheme allows one to use a weak-coupling system to adiabatically prepare the highly entangled ground state of the ultrastrong coupling system. The resulting state could be used for remote entanglement applications.
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Affiliation(s)
- C Leroux
- Department of Physics, McGill University, 3600 rue University, Montréal, Québec, Canada H3A 2T8
| | - L C G Govia
- Institute for Molecular Engineering, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, USA
| | - A A Clerk
- Institute for Molecular Engineering, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, USA
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25
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Armata F, Calajo G, Jaako T, Kim MS, Rabl P. Harvesting Multiqubit Entanglement from Ultrastrong Interactions in Circuit Quantum Electrodynamics. PHYSICAL REVIEW LETTERS 2017; 119:183602. [PMID: 29219543 DOI: 10.1103/physrevlett.119.183602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Indexed: 06/07/2023]
Abstract
We analyze a multiqubit circuit QED system in the regime where the qubit-photon coupling dominates over the system's bare energy scales. Under such conditions a manifold of low-energy states with a high degree of entanglement emerges. Here we describe a time-dependent protocol for extracting these quantum correlations and converting them into well-defined multipartite entangled states of noninteracting qubits. Based on a combination of various ultrastrong-coupling effects, the protocol can be operated in a fast and robust manner, while still being consistent with experimental constraints on switching times and typical energy scales encountered in superconducting circuits. Therefore, our scheme can serve as a probe for otherwise inaccessible correlations in strongly coupled circuit QED systems. It also shows how such correlations can potentially be exploited as a resource for entanglement-based applications.
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Affiliation(s)
- F Armata
- QOLS and QuEST, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - G Calajo
- Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, 1040 Vienna, Austria
| | - T Jaako
- Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, 1040 Vienna, Austria
| | - M S Kim
- QOLS and QuEST, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
- Korea Institute of Advanced Study, Dongdaemun-gu, Seoul 02455, South Korea
| | - P Rabl
- Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, 1040 Vienna, Austria
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26
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Cárdenas-López FA, Albarrán-Arriagada F, Barrios GA, Retamal JC, Romero G. Incoherent-mediator for quantum state transfer in the ultrastrong coupling regime. Sci Rep 2017. [PMID: 28646203 PMCID: PMC5482826 DOI: 10.1038/s41598-017-04467-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We study quantum state transfer between two qubits coupled to a common quantum bus that is constituted by an ultrastrong coupled light-matter system. By tuning both qubit frequencies on resonance with a forbidden transition in the mediating system, we demonstrate a high-fidelity swap operation even though the quantum bus is thermally populated. We discuss a possible physical implementation in a realistic circuit QED scheme that leads to the multimode Dicke model. This proposal may have applications on hot quantum information processing within the context of ultrastrong coupling regime of light-matter interaction.
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Affiliation(s)
- F A Cárdenas-López
- Departamento de Física, Universidad de Santiago de Chile (USACH), Avenida Ecuador 3493, 9170124, Santiago, Chile. .,Center for the Development of Nanoscience and Nanotechnology, 9170124, Estación Central, Santiago, Chile.
| | - F Albarrán-Arriagada
- Departamento de Física, Universidad de Santiago de Chile (USACH), Avenida Ecuador 3493, 9170124, Santiago, Chile
| | - G Alvarado Barrios
- Departamento de Física, Universidad de Santiago de Chile (USACH), Avenida Ecuador 3493, 9170124, Santiago, Chile
| | - J C Retamal
- Departamento de Física, Universidad de Santiago de Chile (USACH), Avenida Ecuador 3493, 9170124, Santiago, Chile. .,Center for the Development of Nanoscience and Nanotechnology, 9170124, Estación Central, Santiago, Chile.
| | - G Romero
- Departamento de Física, Universidad de Santiago de Chile (USACH), Avenida Ecuador 3493, 9170124, Santiago, Chile.
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27
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Wang Y, Guo C, Zhang GQ, Wang G, Wu C. Ultrafast quantum computation in ultrastrongly coupled circuit QED systems. Sci Rep 2017; 7:44251. [PMID: 28281654 PMCID: PMC5345051 DOI: 10.1038/srep44251] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 02/03/2017] [Indexed: 11/18/2022] Open
Abstract
The latest technological progress of achieving the ultrastrong-coupling regime in circuit quantum electrodynamics (QED) systems has greatly promoted the developments of quantum physics, where novel quantum optics phenomena and potential computational benefits have been predicted. Here, we propose a scheme to accelerate the nontrivial two-qubit phase gate in a circuit QED system, where superconducting flux qubits are ultrastrongly coupled to a transmission line resonator (TLR), and two more TLRs are coupled to the ultrastrongly-coupled system for assistant. The nontrivial unconventional geometric phase gate between the two flux qubits is achieved based on close-loop displacements of the three-mode intracavity fields. Moreover, as there are three resonators contributing to the phase accumulation, the requirement of the coupling strength to realize the two-qubit gate can be reduced. Further reduction in the coupling strength to achieve a specific controlled-phase gate can be realized by adding more auxiliary resonators to the ultrastrongly-coupled system through superconducting quantum interference devices. We also present a study of our scheme with realistic parameters considering imperfect controls and noisy environment. Our scheme possesses the merits of ultrafastness and noise-tolerance due to the advantages of geometric phases.
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Affiliation(s)
- Yimin Wang
- College of Communications Engineering, PLA University of Science and Technology, Nanjing 210007, China.,Quantum Physics and Quantum Information Division, Beijing Computational Science Research Center, Beijing 100193, China
| | - Chu Guo
- Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, 487372, Singapore
| | - Guo-Qiang Zhang
- Quantum Physics and Quantum Information Division, Beijing Computational Science Research Center, Beijing 100193, China
| | - Gangcheng Wang
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun 130024, China
| | - Chunfeng Wu
- Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, 487372, Singapore
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28
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Abstract
Understanding the interaction between light and matter is very relevant for fundamental studies of quantum electrodynamics and for the development of quantum technologies. The quantum Rabi model captures the physics of a single atom interacting with a single photon at all regimes of coupling strength. We report the spectroscopic observation of a resonant transition that breaks a selection rule in the quantum Rabi model, implemented using an LC resonator and an artificial atom, a superconducting qubit. The eigenstates of the system consist of a superposition of bare qubit-resonator states with a relative sign. When the qubit-resonator coupling strength is negligible compared to their own frequencies, the matrix element between excited eigenstates of different sign is very small in presence of a resonator drive, establishing a sign-preserving selection rule. Here, our qubit-resonator system operates in the ultrastrong coupling regime, where the coupling strength is 10% of the resonator frequency, allowing sign-changing transitions to be activated and, therefore, detected. This work shows that sign-changing transitions are an unambiguous, distinctive signature of systems operating in the ultrastrong coupling regime of the quantum Rabi model. These results pave the way to further studies of sign-preserving selection rules in multiqubit and multiphoton models.
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29
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Luo MX, Li HR, Lai H, Wang X. Quantum Computation Based on Photons with Three Degrees of Freedom. Sci Rep 2016; 6:25977. [PMID: 27174302 PMCID: PMC4865807 DOI: 10.1038/srep25977] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 04/26/2016] [Indexed: 11/26/2022] Open
Abstract
Quantum systems are important resources for quantum computer. Different from previous encoding forms using quantum systems with one degree of freedom (DoF) or two DoFs, we investigate the possibility of photon systems encoding with three DoFs consisting of the polarization DoF and two spatial DoFs. By exploring the optical circular birefringence induced by an NV center in a diamond embedded in the photonic crystal cavity, we propose several hybrid controlled-NOT (hybrid CNOT) gates operating on the two-photon or one-photon system. These hybrid CNOT gates show that three DoFs may be encoded as independent qubits without auxiliary DoFs. Our result provides a useful way to reduce quantum simulation resources by exploring complex quantum systems for quantum applications requiring large qubit systems.
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Affiliation(s)
- Ming-Xing Luo
- Information Security and National Computing Grid Laboratory, Southwest Jiaotong University, Chengdu 610031, China
| | - Hui-Ran Li
- Information Security and National Computing Grid Laboratory, Southwest Jiaotong University, Chengdu 610031, China
| | - Hong Lai
- School of Computer and Information Science, Southwest University, Chongqing 400715, China
| | - Xiaojun Wang
- School of Electronic Engineering, Dublin City University, Dublin 9, Ireland
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30
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Parity-dependent State Engineering and Tomography in the ultrastrong coupling regime. Sci Rep 2015; 5:11818. [PMID: 26152809 PMCID: PMC5155612 DOI: 10.1038/srep11818] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 06/08/2015] [Indexed: 11/28/2022] Open
Abstract
Reaching the strong coupling regime of light-matter interaction has led to an impressive development in fundamental quantum physics and applications to quantum information processing. Latests advances in different quantum technologies, like superconducting circuits or semiconductor quantum wells, show that the ultrastrong coupling regime (USC) can also be achieved, where novel physical phenomena and potential computational benefits have been predicted. Nevertheless, the lack of effective decoupling mechanism in this regime has so far hindered control and measurement processes. Here, we propose a method based on parity symmetry conservation that allows for the generation and reconstruction of arbitrary states in the ultrastrong coupling regime of light-matter interactions. Our protocol requires minimal external resources by making use of the coupling between the USC system and an ancillary two-level quantum system.
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31
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Sánchez-Burillo E, García-Ripoll J, Martín-Moreno L, Zueco D. Nonlinear quantum optics in the (ultra)strong light-matter coupling. Faraday Discuss 2015; 178:335-56. [PMID: 25760380 DOI: 10.1039/c4fd00206g] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The propagation of N photons in one dimensional waveguides coupled to M qubits is discussed, both in the strong and ultrastrong qubit-waveguide coupling. Special emphasis is placed on the characterisation of the nonlinear response and its linear limit for the scattered photons as a function of N, M, qubit inter distance and light-matter coupling. The quantum evolution is numerically solved via the matrix product states technique. The time evolutions for both the field and qubits are computed. The nonlinear character (as a function of N/M) depends on the computed observable. While perfect reflection is obtained for N/M≅1, photon-photon correlations are still resolved for ratios N/M=non-zero. Inter-qubit distance enhances the nonlinear response. Moving to the ultrastrong coupling regime, we observe that inelastic processes are robust against the number of qubits and that the qubit-qubit interaction mediated by the photons is qualitatively modified. The theory developed in this work models experiments in circuit QED, photonic crystals and dielectric waveguides.
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Affiliation(s)
- Eduardo Sánchez-Burillo
- Instituto de Ciencia de Materiales de Aragón y Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza, Zaragoza, E-50009, Spain
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32
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Kyaw TH, Felicetti S, Romero G, Solano E, Kwek LC. Scalable quantum memory in the ultrastrong coupling regime. Sci Rep 2015; 5:8621. [PMID: 25727251 PMCID: PMC4345319 DOI: 10.1038/srep08621] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/27/2015] [Indexed: 11/09/2022] Open
Abstract
Circuit quantum electrodynamics, consisting of superconducting artificial atoms coupled to on-chip resonators, represents a prime candidate to implement the scalable quantum computing architecture because of the presence of good tunability and controllability. Furthermore, recent advances have pushed the technology towards the ultrastrong coupling regime of light-matter interaction, where the qubit-resonator coupling strength reaches a considerable fraction of the resonator frequency. Here, we propose a qubit-resonator system operating in that regime, as a quantum memory device and study the storage and retrieval of quantum information in and from the Z2 parity-protected quantum memory, within experimentally feasible schemes. We are also convinced that our proposal might pave a way to realize a scalable quantum random-access memory due to its fast storage and readout performances.
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Affiliation(s)
- T H Kyaw
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore
| | - S Felicetti
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, E-48080 Bilbao, Spain
| | - G Romero
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, E-48080 Bilbao, Spain
| | - E Solano
- 1] Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, E-48080 Bilbao, Spain [2] IKERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, 48013 Bilbao, Spain
| | - L-C Kwek
- 1] Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore [2] Institute of Advanced Studies, Nanyang Technological University, 60 Nanyang View, Singapore 639673, Singapore [3] National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Singapore
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33
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Sanchez-Burillo E, Zueco D, Garcia-Ripoll JJ, Martin-Moreno L. Scattering in the ultrastrong regime: nonlinear optics with one photon. PHYSICAL REVIEW LETTERS 2014; 113:263604. [PMID: 25615332 DOI: 10.1103/physrevlett.113.263604] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Indexed: 06/04/2023]
Abstract
The scattering of a flying photon by a two-level system ultrastrongly coupled to a one-dimensional photonic waveguide is studied numerically. The photonic medium is modeled as an array of coupled cavities and the whole system is analyzed beyond the rotating wave approximation using matrix product states. It is found that the scattering is strongly influenced by the single- and multiphoton dressed bound states present in the system. In the ultrastrong coupling regime a new channel for inelastic scattering appears, where an incident photon deposits energy into the qubit, exciting a photon-bound state, and escaping with a lower frequency. This single-photon nonlinear frequency conversion process can reach up to 50% efficiency. Other remarkable features in the scattering induced by counterrotating terms are a blueshift of the reflection resonance and a Fano resonance due to long-lived excited states.
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Affiliation(s)
- E Sanchez-Burillo
- Instituto de Ciencia de Materiales de Aragon and Departamento de Fisica de la Materia Condensada, CSIC-Universidad de Zaragoza, E-50012 Zaragoza, Spain
| | - D Zueco
- Instituto de Ciencia de Materiales de Aragon and Departamento de Fisica de la Materia Condensada, CSIC-Universidad de Zaragoza, E-50012 Zaragoza, Spain and Fundacion ARAID, Paseo Maria Agustin 36, E-50004 Zaragoza, Spain
| | - J J Garcia-Ripoll
- Instituto de Fisica Fundamental, IFF-CSIC, Calle Serrano 113b, E-28006 Madrid, Spain
| | - L Martin-Moreno
- Instituto de Ciencia de Materiales de Aragon and Departamento de Fisica de la Materia Condensada, CSIC-Universidad de Zaragoza, E-50012 Zaragoza, Spain
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34
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Wei HR, Deng FG. Scalable quantum computing based on stationary spin qubits in coupled quantum dots inside double-sided optical microcavities. Sci Rep 2014; 4:7551. [PMID: 25518899 PMCID: PMC4269895 DOI: 10.1038/srep07551] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 12/01/2014] [Indexed: 11/26/2022] Open
Abstract
Quantum logic gates are the key elements in quantum computing. Here we investigate the possibility of achieving a scalable and compact quantum computing based on stationary electron-spin qubits, by using the giant optical circular birefringence induced by quantum-dot spins in double-sided optical microcavities as a result of cavity quantum electrodynamics. We design the compact quantum circuits for implementing universal and deterministic quantum gates for electron-spin systems, including the two-qubit CNOT gate and the three-qubit Toffoli gate. They are compact and economic, and they do not require additional electron-spin qubits. Moreover, our devices have good scalability and are attractive as they both are based on solid-state quantum systems and the qubits are stationary. They are feasible with the current experimental technology, and both high fidelity and high efficiency can be achieved when the ratio of the side leakage to the cavity decay is low.
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Affiliation(s)
- Hai-Rui Wei
- Department of Physics, Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Fu-Guo Deng
- Department of Physics, Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
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35
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Bassett LC, Heremans FJ, Christle DJ, Yale CG, Burkard G, Buckley BB, Awschalom DD. Ultrafast optical control of orbital and spin dynamics in a solid-state defect. Science 2014; 345:1333-7. [PMID: 25123482 DOI: 10.1126/science.1255541] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Atom-scale defects in semiconductors are promising building blocks for quantum devices, but our understanding of their material-dependent electronic structure, optical interactions, and dissipation mechanisms is lacking. Using picosecond resonant pulses of light, we study the coherent orbital and spin dynamics of a single nitrogen-vacancy center in diamond over time scales spanning six orders of magnitude. We develop a time-domain quantum tomography technique to precisely map the defect's excited-state Hamiltonian and exploit the excited-state dynamics to control its ground-state spin with optical pulses alone. These techniques generalize to other optically addressable nanoscale spin systems and serve as powerful tools to characterize and control spin qubits for future applications in quantum technology.
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Affiliation(s)
- Lee C Bassett
- Center for Spintronics and Quantum Computation, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - F Joseph Heremans
- Center for Spintronics and Quantum Computation, University of California, Santa Barbara, Santa Barbara, CA 93106, USA. Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - David J Christle
- Center for Spintronics and Quantum Computation, University of California, Santa Barbara, Santa Barbara, CA 93106, USA. Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Christopher G Yale
- Center for Spintronics and Quantum Computation, University of California, Santa Barbara, Santa Barbara, CA 93106, USA. Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Guido Burkard
- Department of Physics, University of Konstanz, D-78457 Konstanz, Germany
| | - Bob B Buckley
- Center for Spintronics and Quantum Computation, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - David D Awschalom
- Center for Spintronics and Quantum Computation, University of California, Santa Barbara, Santa Barbara, CA 93106, USA. Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA.
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36
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Muralidharan S, Kim J, Lütkenhaus N, Lukin MD, Jiang L. Ultrafast and fault-tolerant quantum communication across long distances. PHYSICAL REVIEW LETTERS 2014; 112:250501. [PMID: 25014798 DOI: 10.1103/physrevlett.112.250501] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Indexed: 06/03/2023]
Abstract
Quantum repeaters (QRs) provide a way of enabling long distance quantum communication by establishing entangled qubits between remote locations. In this Letter, we investigate a new approach to QRs in which quantum information can be faithfully transmitted via a noisy channel without the use of long distance teleportation, thus eliminating the need to establish remote entangled links. Our approach makes use of small encoding blocks to fault-tolerantly correct both operational and photon loss errors. We describe a way to optimize the resource requirement for these QRs with the aim of the generation of a secure key. Numerical calculations indicate that the number of quantum memory bits at each repeater station required for the generation of one secure key has favorable polylogarithmic scaling with the distance across which the communication is desired.
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Affiliation(s)
- Sreraman Muralidharan
- Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511, USA
| | - Jungsang Kim
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Norbert Lütkenhaus
- Institute of Quantum computing, University of Waterloo, N2L 3G1 Waterloo, Canada
| | - Mikhail D Lukin
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Liang Jiang
- Department of Applied Physics, Yale University, New Haven, Connecticut 06511, USA
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37
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Naether U, García-Ripoll JJ, Mazo JJ, Zueco D. Quantum chaos in an ultrastrongly coupled bosonic junction. PHYSICAL REVIEW LETTERS 2014; 112:074101. [PMID: 24579602 DOI: 10.1103/physrevlett.112.074101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Indexed: 06/03/2023]
Abstract
The semiclassical and quantum dynamics of two ultrastrongly coupled nonlinear resonators cannot be explained using the discrete nonlinear Schrödinger equation or the Bose-Hubbard model, respectively. Instead, a model beyond the rotating wave approximation must be studied. In the semiclassical limit this model is not integrable and becomes chaotic for a finite window of parameters. For the quantum dimer we find corresponding regions of stability and chaos. The more striking consequence for both semiclassical and quantum chaos is that the tunneling time between the sites becomes unpredictable. These results, including the transition to chaos, can be tested in experiments with superconducting microwave resonators.
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Affiliation(s)
- Uta Naether
- Instituto de Ciencia de Materiales de Aragón and Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
| | | | - Juan José Mazo
- Instituto de Ciencia de Materiales de Aragón and Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - David Zueco
- Instituto de Ciencia de Materiales de Aragón and Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain and Fundación ARAID, Paseo María Agustín 36, 50004 Zaragoza, Spain
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38
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Albert VV. Quantum Rabi model for N-state atoms. PHYSICAL REVIEW LETTERS 2012; 108:180401. [PMID: 22681049 DOI: 10.1103/physrevlett.108.180401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 03/04/2012] [Indexed: 06/01/2023]
Abstract
A tractable N-state Rabi Hamiltonian is introduced by extending the parity symmetry of the two-state model. The single-mode case provides a few-parameter description of a novel class of periodic systems, predicting that the ground state of certain four-state atom-cavity systems will undergo parity change at strong-coupling. A group-theoretical treatment provides physical insight into dynamics and a modified rotating wave approximation obtains accurate analytical energies. The dissipative case can be applied to study excitation energy transfer in molecular rings or chains.
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Affiliation(s)
- Victor V Albert
- Department of Physics, Yale University, P.O. Box 208120, New Haven, Connecticut 06520-8120, USA.
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