1
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Chen YH, Shi ZC, Nori F, Xia Y. Error-Tolerant Amplification and Simulation of the Ultrastrong-Coupling Quantum Rabi Model. PHYSICAL REVIEW LETTERS 2024; 133:033603. [PMID: 39094163 DOI: 10.1103/physrevlett.133.033603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 06/18/2024] [Indexed: 08/04/2024]
Abstract
Cat-state qubits formed by photonic cat states have a biased noise channel, i.e., one type of error dominates over all the others. We demonstrate that such biased-noise qubits are also promising for error-tolerant simulations of the quantum Rabi model (and its varieties) by coupling a cat-state qubit to an optical cavity. Using the cat-state qubit can effectively enhance the counterrotating coupling, allowing us to explore several fascinating quantum phenomena relying on the counterrotating interaction. Moreover, another benefit from biased-noise cat qubits is that the two main error channels (frequency and amplitude mismatches) are both exponentially suppressed. Therefore, the simulation protocols are robust against parameter errors of the parametric drive that determines the projection subspace. We analyze three examples: (i) collapse and revivals of quantum states; (ii) hidden symmetry and tunneling dynamics; and (iii) pair-cat-code computation.
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Affiliation(s)
- Ye-Hong Chen
- Fujian Key Laboratory of Quantum Information and Quantum Optics, Fuzhou University, Fuzhou 350116, China
- Department of Physics, Fuzhou University, Fuzhou 350116, China
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
| | | | - Franco Nori
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- Quantum Information Physics Theory Research Team, RIKEN Center for Quantum Computing, Wako-shi, Saitama 351-0198, Japan
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040, USA
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2
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Herrera Romero R, Bastarrachea-Magnani MA. Phase and Amplitude Modes in the Anisotropic Dicke Model with Matter Interactions. ENTROPY (BASEL, SWITZERLAND) 2024; 26:574. [PMID: 39056936 PMCID: PMC11276390 DOI: 10.3390/e26070574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2024] [Revised: 06/29/2024] [Accepted: 07/01/2024] [Indexed: 07/28/2024]
Abstract
Phase and amplitude modes, also called polariton modes, are emergent phenomena that manifest across diverse physical systems, from condensed matter and particle physics to quantum optics. We study their behavior in an anisotropic Dicke model that includes collective matter interactions. We study the low-lying spectrum in the thermodynamic limit via the Holstein-Primakoff transformation and contrast the results with the semi-classical energy surface obtained via coherent states. We also explore the geometric phase for both boson and spin contours in the parameter space as a function of the phases in the system. We unveil novel phenomena due to the unique critical features provided by the interplay between the anisotropy and matter interactions. We expect our results to serve the observation of phase and amplitude modes in current quantum information platforms.
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Affiliation(s)
| | - Miguel Angel Bastarrachea-Magnani
- Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, Av. Ferrocarril San Rafael Atlixco 186, Mexico City C.P. 09310, Mexico
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3
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Wang Y, Zhang Y, Li C, Wei J, He B, Xu H, Xia J, Luo X, Li J, Dong J, He W, Yan Z, Yang W, Ma F, Chai G, Yan P, Wan C, Han X, Yu G. Ultrastrong to nearly deep-strong magnon-magnon coupling with a high degree of freedom in synthetic antiferromagnets. Nat Commun 2024; 15:2077. [PMID: 38453947 PMCID: PMC10920873 DOI: 10.1038/s41467-024-46474-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 02/28/2024] [Indexed: 03/09/2024] Open
Abstract
Ultrastrong and deep-strong coupling are two coupling regimes rich in intriguing physical phenomena. Recently, hybrid magnonic systems have emerged as promising candidates for exploring these regimes, owing to their unique advantages in quantum engineering. However, because of the relatively weak coupling between magnons and other quasiparticles, ultrastrong coupling is predominantly realized at cryogenic temperatures, while deep-strong coupling remains to be explored. In our work, we achieve both theoretical and experimental realization of room-temperature ultrastrong magnon-magnon coupling in synthetic antiferromagnets with intrinsic asymmetry of magnetic anisotropy. Unlike most ultrastrong coupling systems, where the counter-rotating coupling strength g2 is strictly equal to the co-rotating coupling strength g1, our systems allow for highly tunable g1 and g2. This high degree of freedom also enables the realization of normalized g1 or g2 larger than 0.5. Particularly, our experimental findings reveal that the maximum observed g1 is nearly identical to the bare frequency, with g1/ω0 = 0.963, indicating a close realization of deep-strong coupling within our hybrid magnonic systems. Our results highlight synthetic antiferromagnets as platforms for exploring unconventional ultrastrong and even deep-strong coupling regimes, facilitating the further exploration of quantum phenomena.
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Affiliation(s)
- Yuqiang Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yu Zhang
- Jiangsu Key Laboratory of Opto-Electronic Technology, School of Physics and Technology, Nanjing Normal University, Nanjing, 210046, China
| | - Chaozhong Li
- Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China
| | - Jinwu Wei
- Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China
| | - Bin He
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hongjun Xu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Jihao Xia
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xuming Luo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jiahui Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jing Dong
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Wenqing He
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhengren Yan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wenlong Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fusheng Ma
- Jiangsu Key Laboratory of Opto-Electronic Technology, School of Physics and Technology, Nanjing Normal University, Nanjing, 210046, China.
| | - Guozhi Chai
- Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China
| | - Peng Yan
- School of Electronic Science and Engineering and State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Caihua Wan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Guoqiang Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China.
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4
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Wang SP, Ridolfo A, Li T, Savasta S, Nori F, Nakamura Y, You JQ. Probing the symmetry breaking of a light-matter system by an ancillary qubit. Nat Commun 2023; 14:4397. [PMID: 37474535 PMCID: PMC10359332 DOI: 10.1038/s41467-023-40097-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 07/11/2023] [Indexed: 07/22/2023] Open
Abstract
Hybrid quantum systems in the ultrastrong, and even more in the deep-strong, coupling regimes can exhibit exotic physical phenomena and promise new applications in quantum technologies. In these nonperturbative regimes, a qubit-resonator system has an entangled quantum vacuum with a nonzero average photon number in the resonator, where the photons are virtual and cannot be directly detected. The vacuum field, however, is able to induce the symmetry breaking of a dispersively coupled probe qubit. We experimentally observe the parity symmetry breaking of an ancillary Xmon artificial atom induced by the field of a lumped-element superconducting resonator deep-strongly coupled with a flux qubit. This result opens a way to experimentally explore the novel quantum-vacuum effects emerging in the deep-strong coupling regime.
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Affiliation(s)
- Shuai-Peng Wang
- Quantum Physics and Quantum Information Division, Beijing Computational Science Research Center, Beijing, 100193, China
- Interdisciplinary Center of Quantum Information, State Key Laboratory of Extreme Photonics and Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, School of Physics, Zhejiang University, Hangzhou, 310027, China
| | - Alessandro Ridolfo
- Dipartimento di Fisica e Astronomia, Università di Catania, 95123, Catania, Italy
| | - Tiefu Li
- School of Integrated Circuits, and Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China.
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China.
| | - Salvatore Savasta
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università di Messina, I-98166, Messina, Italy.
| | - Franco Nori
- Theoretical Quantum Physics Laboratory, Cluster for Pioneering Research, RIKEN, Wako, Saitama, 351-0198, Japan
- Physics Department, The University of Michigan, Ann Arbor, MI, 48109-1040, USA
- RIKEN Center for Quantum Computing (RQC), Wako, Saitama, 351-0198, Japan
| | - Y Nakamura
- RIKEN Center for Quantum Computing (RQC), Wako, Saitama, 351-0198, Japan
- Department of Applied Physics, Graduate School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - J Q You
- Interdisciplinary Center of Quantum Information, State Key Laboratory of Extreme Photonics and Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, School of Physics, Zhejiang University, Hangzhou, 310027, China.
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5
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Wang CY, Zheng YJ, Wei MS, Liao MJ, Lin ZJ, Wang C, Yang YP, Xu JP. Influence of a topological artificial atom chain on the transmission properties of a cavity. OPTICS EXPRESS 2023; 31:15342-15354. [PMID: 37157638 DOI: 10.1364/oe.485884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We explore the influence of the artificial atomic chain on the input-output relation of the cavity. Specifically, we extend the atom chain to the one-dimensional Su-Schrieffer-Heeger (SSH) chain to check the role of atomic topological non-trivial edge state on the transmission characteristics of the cavity. The superconducting circuits can realize the artificial atomic chain. Our results show that the atom chain is not equivalent to atom gas, and the transmission properties of the cavity containing the atom chain are entirely different from that of the cavity containing atom gas. When the atom chain is arranged in the form of topological non-trivial SSH model, the atom chain can be equivalent to the three-level atom, in which the edge state contributes to the second level and is resonant with the cavity, while the high-energy bulk state contributes to form the third level and is greatly detuned with the cavity. Therefore, the transmission spectrum shows no more than three peaks. This allows us to infer the topological phase of the atomic chain and the coupling strength between the atom and the cavity only from the profile of the transmission spectrum. Our work is helping to understand the role of topology in quantum optics.
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6
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Lindel F, Carnio EG, Buhmann SY, Buchleitner A. Quantized Fields for Optimal Control in the Strong Coupling Regime. PHYSICAL REVIEW LETTERS 2023; 130:133601. [PMID: 37067298 DOI: 10.1103/physrevlett.130.133601] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 01/16/2023] [Accepted: 02/16/2023] [Indexed: 06/19/2023]
Abstract
We tailor the quantum statistics of a bosonic field to deterministically drive a quantum system into a target state. Experimentally accessible states of the field achieve good control of multilevel or multiqubit systems, notably also at coupling strengths beyond the rotating-wave approximation. This extends optimal control theory to the realm of fully quantized, strongly coupled control and target degrees of freedom.
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Affiliation(s)
- Frieder Lindel
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104, Freiburg, Germany
| | - Edoardo G Carnio
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104, Freiburg, Germany
- EUCOR Centre for Quantum Science and Quantum Computing, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104, Freiburg, Germany
| | - Stefan Yoshi Buhmann
- Institut für Physik, Universität Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Andreas Buchleitner
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104, Freiburg, Germany
- EUCOR Centre for Quantum Science and Quantum Computing, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104, Freiburg, Germany
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7
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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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8
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Herrera Romero R, Bastarrachea-Magnani MA, Linares R. Critical Phenomena in Light-Matter Systems with Collective Matter Interactions. ENTROPY (BASEL, SWITZERLAND) 2022; 24:1198. [PMID: 36141084 PMCID: PMC9497676 DOI: 10.3390/e24091198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 08/20/2022] [Accepted: 08/23/2022] [Indexed: 06/16/2023]
Abstract
We study the quantum phase diagram and the onset of quantum critical phenomena in a generalized Dicke model that includes collective qubit-qubit interactions. By employing semiclassical techniques, we analyze the corresponding classical energy surfaces, fixed points, and the smooth Density of States as a function of the Hamiltonian parameters to determine quantum phase transitions in either the ground (QPT) or excited states (ESQPT). We unveil a rich phase diagram, the presence of new phases, and new transitions that result from varying the strength of the qubits interactions in independent canonical directions. We also find a correspondence between the phases emerging due to qubit interactions and those in their absence but with varying the strength of the non-resonant terms in the light-matter coupling. We expect our work to pave the way and stimulate the exploration of quantum criticality in systems combining matter-matter and light-matter interactions.
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9
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Bonini J, Flick J. Ab Initio Linear-Response Approach to Vibro-Polaritons in the Cavity Born-Oppenheimer Approximation. J Chem Theory Comput 2022; 18:2764-2773. [PMID: 35404591 PMCID: PMC9097282 DOI: 10.1021/acs.jctc.1c01035] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Indexed: 11/28/2022]
Abstract
Recent years have seen significant developments in the study of strong light-matter coupling including the control of chemical reactions by altering the vibrational normal modes of molecules. In the vibrational strong coupling regime, the normal modes of the system become hybrid modes which mix nuclear, electronic, and photonic degrees of freedom. First-principles methods capable of treating light and matter degrees of freedom on the same level of theory are an important tool in understanding such systems. In this work, we develop and apply a generalized force constant matrix approach to the study of mixed vibration-photon (vibro-polariton) states of molecules based on the cavity Born-Oppenheimer approximation and quantum-electrodynamical density-functional theory. With this method, vibro-polariton modes and infrared spectra can be computed via linear-response techniques analogous to those widely used for conventional vibrations and phonons. We also develop an accurate model that highlights the consistent treatment of cavity-coupled electrons in the vibrational strong coupling regime. These electronic effects appear as new terms previously disregarded by simpler models. This effective model also allows for an accurate extrapolation of single and two molecule calculations to the collective strong coupling limit of hundreds of molecules. We benchmark these approaches for single and many CO2 molecules coupled to a single photon mode and the iron pentacarbonyl Fe(CO)5 molecule coupled to a few photon modes. Our results are the first ab initio results for collective vibrational strong coupling effects. This framework for efficient computations of vibro-polaritons paves the way to a systematic description and improved understanding of the behavior of chemical systems in vibrational strong coupling.
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Affiliation(s)
- John Bonini
- Center for Computational Quantum Physics, Flatiron Institute, 162 Fifth Ave., New York, New York 10010, United States
| | - Johannes Flick
- Center for Computational Quantum Physics, Flatiron Institute, 162 Fifth Ave., New York, New York 10010, United States
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10
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Microcavity phonon polaritons from the weak to the ultrastrong phonon-photon coupling regime. Nat Commun 2021; 12:6206. [PMID: 34707119 PMCID: PMC8551273 DOI: 10.1038/s41467-021-26060-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 09/08/2021] [Indexed: 11/30/2022] Open
Abstract
Strong coupling between molecular vibrations and microcavity modes has been demonstrated to modify physical and chemical properties of the molecular material. Here, we study the less explored coupling between lattice vibrations (phonons) and microcavity modes. Embedding thin layers of hexagonal boron nitride (hBN) into classical microcavities, we demonstrate the evolution from weak to ultrastrong phonon-photon coupling when the hBN thickness is increased from a few nanometers to a fully filled cavity. Remarkably, strong coupling is achieved for hBN layers as thin as 10 nm. Further, the ultrastrong coupling in fully filled cavities yields a polariton dispersion matching that of phonon polaritons in bulk hBN, highlighting that the maximum light-matter coupling in microcavities is limited to the coupling strength between photons and the bulk material. Tunable cavity phonon polaritons could become a versatile platform for studying how the coupling strength between photons and phonons may modify the properties of polar crystals. Strong coupling between light and matter can be engineered to influence their properties and behaviour. Here, the authors demonstrate the evolution from weak to ultrastrong coupling of microcavity modes and optical phonons with hexagonal boron nitride layers in a Fabry-Perot resonator.
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11
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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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12
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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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13
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Ashida Y, İmamoğlu A, Demler E. Cavity Quantum Electrodynamics at Arbitrary Light-Matter Coupling Strengths. PHYSICAL REVIEW LETTERS 2021; 126:153603. [PMID: 33929218 DOI: 10.1103/physrevlett.126.153603] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
Quantum light-matter systems at strong coupling are notoriously challenging to analyze due to the need to include states with many excitations in every coupled mode. We propose a nonperturbative approach to analyze light-matter correlations at all interaction strengths. The key element of our approach is a unitary transformation that achieves asymptotic decoupling of light and matter degrees of freedom in the limit where light-matter interaction becomes the dominant energy scale. In the transformed frame, truncation of the matter or photon Hilbert space is increasingly well justified at larger coupling, enabling one to systematically derive low-energy effective models, such as tight-binding Hamiltonians. We demonstrate the versatility of our approach by applying it to concrete models relevant to electrons in crystal potential and electric dipoles interacting with a cavity mode. A generalization to the case of spatially varying electromagnetic modes is also discussed.
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Affiliation(s)
- Yuto Ashida
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Institute for Physics of Intelligence, University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan
- Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Ataç İmamoğlu
- Institute of Quantum Electronics, ETH Zurich, CH-8093 Zürich, Switzerland
| | - Eugene Demler
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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14
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Flick J, Narang P. Ab initio polaritonic potential-energy surfaces for excited-state nanophotonics and polaritonic chemistry. J Chem Phys 2020; 153:094116. [PMID: 32891103 DOI: 10.1063/5.0021033] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Advances in nanophotonics, quantum optics, and low-dimensional materials have enabled precise control of light-matter interactions down to the nanoscale. Combining concepts from each of these fields, there is now an opportunity to create and manipulate photonic matter via strong coupling of molecules to the electromagnetic field. Toward this goal, here we demonstrate a first principles framework to calculate polaritonic excited-state potential-energy surfaces, transition dipole moments, and transition densities for strongly coupled light-matter systems. In particular, we demonstrate the applicability of our methodology by calculating the polaritonic excited-state manifold of a formaldehyde molecule strongly coupled to an optical cavity. This proof-of-concept calculation shows how strong coupling can be exploited to alter photochemical reaction pathways by influencing avoided crossings with tuning of the cavity frequency and coupling strength. Therefore, by introducing an ab initio method to calculate excited-state potential-energy surfaces, our work opens a new avenue for the field of polaritonic chemistry.
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Affiliation(s)
- Johannes Flick
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Prineha Narang
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
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15
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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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16
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Zhu CJ, Ping LL, Yang YP, Agarwal GS. Squeezed Light Induced Symmetry Breaking Superradiant Phase Transition. PHYSICAL REVIEW LETTERS 2020; 124:073602. [PMID: 32142326 DOI: 10.1103/physrevlett.124.073602] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 01/22/2020] [Indexed: 06/10/2023]
Abstract
We theoretically investigate the quantum phase transition in the collective systems of qubits in a high quality cavity, where the cavity field is squeezed via the optical parametric amplification process. We show that the squeezed light induced symmetry breaking can result in quantum phase transition without the ultrastrong coupling requirement. Using the standard mean field theory, we derive the condition of the quantum phase transition. Surprisingly, we show that there exists a tricritical point where the first- and second-order phase transitions meet. With specific atom-cavity coupling strengths, both the first- and second-order phase transition can be controlled by the nonlinear gain coefficient, which is sensitive to the pump field. These features also lead to an optical switching from the normal phase to the superradiant phase by just increasing the pump field intensity. The signature of these phase transitions can be observed by detecting the phase space Wigner function distribution with different profiles controlled by the squeezed light intensity. Such superradiant phase transition can be implemented in various quantum systems, including atoms, quantum dots, and ions in optical cavities as well as the circuit quantum electrodynamics system.
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Affiliation(s)
- C J Zhu
- MOE Key Laboratory of Advanced Micro-Structured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - L L Ping
- MOE Key Laboratory of Advanced Micro-Structured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Y P Yang
- MOE Key Laboratory of Advanced Micro-Structured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - G S Agarwal
- Institute for Quantum Science and Engineering, and Department of Biological and Agricultural Engineering Texas, A&M University, College Station, Texas 77843, USA
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17
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Hirai K, Takeda R, Hutchison JA, Uji‐i H. Modulation of Prins Cyclization by Vibrational Strong Coupling. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201915632] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Kenji Hirai
- Division of Photonics and Optical Science Research Institute for Electronic Science (RIES) Hokkaido University North 20 West 10, Kita ward Sapporo Hokkaido Japan
- Precursory Research for Embryonic Science and Technology (PRESTO) (Japan) Science and Technology Agency (JST) 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan
- Division of Information Science and Technology Graduate School of Information Science and Technology Hokkaido University North 14 West 9, Kita ward Sapporo Hokkaido Japan
| | - Rie Takeda
- Division of Photonics and Optical Science Research Institute for Electronic Science (RIES) Hokkaido University North 20 West 10, Kita ward Sapporo Hokkaido Japan
- Precursory Research for Embryonic Science and Technology (PRESTO) (Japan) Science and Technology Agency (JST) 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan
| | - James A. Hutchison
- School of Chemistry The University of Melbourne Masson Rd Parkville VIC 3052 Australia
| | - Hiroshi Uji‐i
- Division of Photonics and Optical Science Research Institute for Electronic Science (RIES) Hokkaido University North 20 West 10, Kita ward Sapporo Hokkaido Japan
- Division of Information Science and Technology Graduate School of Information Science and Technology Hokkaido University North 14 West 9, Kita ward Sapporo Hokkaido Japan
- Department of Chemistry Katholieke Universiteit Leuven Celestijnenlaan 200F, 3001 Heverlee Leuven Belgium
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18
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Hirai K, Takeda R, Hutchison JA, Uji‐i H. Modulation of Prins Cyclization by Vibrational Strong Coupling. Angew Chem Int Ed Engl 2020; 59:5332-5335. [DOI: 10.1002/anie.201915632] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 01/15/2020] [Indexed: 11/10/2022]
Affiliation(s)
- Kenji Hirai
- Division of Photonics and Optical Science Research Institute for Electronic Science (RIES) Hokkaido University North 20 West 10, Kita ward Sapporo Hokkaido Japan
- Precursory Research for Embryonic Science and Technology (PRESTO) (Japan) Science and Technology Agency (JST) 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan
- Division of Information Science and Technology Graduate School of Information Science and Technology Hokkaido University North 14 West 9, Kita ward Sapporo Hokkaido Japan
| | - Rie Takeda
- Division of Photonics and Optical Science Research Institute for Electronic Science (RIES) Hokkaido University North 20 West 10, Kita ward Sapporo Hokkaido Japan
- Precursory Research for Embryonic Science and Technology (PRESTO) (Japan) Science and Technology Agency (JST) 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan
| | - James A. Hutchison
- School of Chemistry The University of Melbourne Masson Rd Parkville VIC 3052 Australia
| | - Hiroshi Uji‐i
- Division of Photonics and Optical Science Research Institute for Electronic Science (RIES) Hokkaido University North 20 West 10, Kita ward Sapporo Hokkaido Japan
- Division of Information Science and Technology Graduate School of Information Science and Technology Hokkaido University North 14 West 9, Kita ward Sapporo Hokkaido Japan
- Department of Chemistry Katholieke Universiteit Leuven Celestijnenlaan 200F, 3001 Heverlee Leuven Belgium
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19
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Felicetti S, Le Boité A. Universal Spectral Features of Ultrastrongly Coupled Systems. PHYSICAL REVIEW LETTERS 2020; 124:040404. [PMID: 32058793 DOI: 10.1103/physrevlett.124.040404] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Indexed: 06/10/2023]
Abstract
We identify universal properties of the low-energy subspace of a wide class of quantum optical models in the ultrastrong coupling limit, where the coupling strength dominates over all other energy scales in the system. We show that the symmetry of the light-matter interaction is at the origin of a twofold degeneracy in the spectrum. We prove analytically this result for bounded Hamiltonians and extend it to a class of models with unbounded operators. As a consequence, we show that the emergence of superradiant phases previously investigated in the context of critical phenomena, is a general property of the ultrastrong coupling limit. The set of models we consider encompasses different scenarios of possible interplay between critical behavior and superradiance.
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Affiliation(s)
- Simone Felicetti
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid E-39049, Spain
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, F-75013 Paris, France
| | - Alexandre Le Boité
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, F-75013 Paris, France
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20
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Abstract
The analytical exact solutions to the mixed quantum Rabi model (QRM) including both one- and two-photon terms are found by using Bogoliubov operators. Transcendental functions in terms of 4 × 4 determinants responsible for the exact solutions are derived. These so-called G-functions with pole structures can be reduced to the previous ones in the unmixed QRMs. The zeros of G-functions reproduce completely the regular spectra. The exceptional eigenvalues can also be obtained by another transcendental function. From the pole structure, we can derive two energy limits when the two-photon coupling strength tends to the collapse point. All energy levels only collapse to the lower one, which diverges negatively. The level crossings in the unmixed QRMs are relaxed to avoided crossings in the present mixed QRM due to absence of parity symmetry. In the weak two-photon coupling regime, the mixed QRM is equivalent to an one-photon QRM with an effective positive bias, suppressed photon frequency and enhanced one-photon coupling, which may pave a highly efficient and economic way to access the deep-strong one-photon coupling regime.
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21
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Hernández FJ, Herrera F. Multi-level quantum Rabi model for anharmonic vibrational polaritons. J Chem Phys 2019; 151:144116. [DOI: 10.1063/1.5121426] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Federico J. Hernández
- Department of Physics, Universidad de Santiago de Chile, Av. Ecuador, 3493 Santiago, Chile
| | - Felipe Herrera
- Department of Physics, Universidad de Santiago de Chile, Av. Ecuador, 3493 Santiago, Chile
- Millennium Institute for Research in Optics MIRO, Concepción, Chile
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22
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Abstract
The quantum Rabi model is the simplest and most important theoretical description of light–matter interaction for all experimentally accessible coupling regimes. It can be solved exactly and is even integrable due to a discrete symmetry, the Z 2 or parity symmetry. All qualitative properties of its spectrum, especially the differences to the Jaynes–Cummings model, which possesses a larger, continuous symmetry, can be understood in terms of the so-called “G-functions” whose zeroes yield the exact eigenvalues of the Rabi Hamiltonian. The special type of integrability appearing in systems with discrete degrees of freedom is responsible for the absence of Poissonian level statistics in the spectrum while its well-known “Juddian” solutions are a natural consequence of the structure of the G-functions. The poles of these functions are known in closed form, which allows drawing conclusions about the global spectrum.
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23
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Mahmoodian S. Chiral Light-Matter Interaction beyond the Rotating-Wave Approximation. PHYSICAL REVIEW LETTERS 2019; 123:133603. [PMID: 31697533 DOI: 10.1103/physrevlett.123.133603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Indexed: 06/10/2023]
Abstract
I introduce and analyze chiral light-matter interaction in the ultrastrong coupling limit where the rotating-wave approximation cannot be made. Within this limit, a two-level system with a circularly polarized transition dipole interacts with a copolarized mode through rotating-wave terms. However, the counterrotating terms allow the two-level system to couple to a counterpolarized mode with the same coupling strength, i.e., one that is completely decoupled within the rotating-wave approximation. Although such a Hamiltonian is not particle number conserving, the conservation of angular momentum generates a U(1) symmetry which allows constructing an ansatz. The eigenstates and dynamics of this novel model are computed for single-cavity interactions and for a many-mode system. The form of the ansatz provides significant analytic insight into the physics of the ground state and the dynamics; e.g., it indicates that the ground states are two-mode squeezed. This work has significant implications for engineering light-matter interaction and novel quantum many-body dynamics beyond the rotating-wave approximation.
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Affiliation(s)
- Sahand Mahmoodian
- Institute for Theoretical Physics, Institute for Gravitational Physics (Albert Einstein Institute), Leibniz University Hannover, Appelstraße 2, 30167 Hannover, Germany
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24
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Piccione N, Militello B, Napoli A, Bellomo B. Simple scheme for extracting work with a single bath. Phys Rev E 2019; 100:032143. [PMID: 31639978 DOI: 10.1103/physreve.100.032143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Indexed: 11/07/2022]
Abstract
We propose a simple protocol exploiting the thermalization of a storage bipartite system S to extract work from a resource system R. The protocol is based on a recent work definition involving only a single bath. A general description of the protocol is provided without specifying the characteristics of S. We quantify both the extracted work and the ideal efficiency of the process, also giving maximum bounds for them. Then, we apply the protocol to two cases: two interacting qubits and the Rabi model. In both cases, for very strong couplings, an extraction of work comparable with the bare energies of the subsystems of S is obtained and its peak is reached for finite values of the bath temperature, T. We finally show, in the Rabi model at T=0, how to transfer the work stored in S to an external device, permitting thus a cyclic implementation of the whole work-extraction protocol. Our proposal makes use of simple operations not needing fine control.
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Affiliation(s)
- Nicolò Piccione
- Institut UTINAM, CNRS UMR 6213, Université Bourgogne Franche-Comté, Observatoire des Sciences de l'Univers THETA, 41 bis avenue de l'Observatoire, F-25010 Besançon, France
| | - Benedetto Militello
- Università degli Studi di Palermo, Dipartimento di Fisica e Chimica - Emilio Segrè, via Archirafi 36, I-90123 Palermo, Italy.,Istituto Nazionale di Fisica Nucleare, Sezione di Catania, via Santa Sofia 64, I-95123 Catania, Italy
| | - Anna Napoli
- Università degli Studi di Palermo, Dipartimento di Fisica e Chimica - Emilio Segrè, via Archirafi 36, I-90123 Palermo, Italy.,Istituto Nazionale di Fisica Nucleare, Sezione di Catania, via Santa Sofia 64, I-95123 Catania, Italy
| | - Bruno Bellomo
- Institut UTINAM, CNRS UMR 6213, Université Bourgogne Franche-Comté, Observatoire des Sciences de l'Univers THETA, 41 bis avenue de l'Observatoire, F-25010 Besançon, France
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25
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Meng F, Thomson MD, Klug B, Čibiraitė D, Ul-Islam Q, Roskos HG. Nonlocal collective ultrastrong interaction of plasmonic metamaterials and photons in a terahertz photonic crystal cavity. OPTICS EXPRESS 2019; 27:24455-24468. [PMID: 31510334 DOI: 10.1364/oe.27.024455] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 07/08/2019] [Indexed: 06/10/2023]
Abstract
Light-matter interaction in the strong coupling regime is of profound interest for fundamental quantum optics, information processing and the realization of ultrahigh-resolution sensors. Here, we report a new way to realize strong light-matter interaction, by coupling metamaterial plasmonic "quasi-particles" with photons in a photonic cavity, in the terahertz frequency range. The resultant cavity polaritons exhibit a splitting which can reach the ultra-strong coupling regime, even with the comparatively low density of quasi-particles, and inherit the high Q-factor of the cavity despite the relatively broad resonances of the Swiss-cross and split-ring-resonator metamaterials used. We also demonstrate nonlocal collective interaction of spatially separated metamaterial layers mediated by the cavity photons. By applying the quantum electrodynamic formalism to the density dependence of the polariton splitting, we can deduce the intrinsic transition dipole moment for single-quantum excitation of the metamaterial quasi-particles, which is orders of magnitude larger than those of natural atoms. These findings are of interest for the investigation of fundamental strong-coupling phenomena, but also for applications such as ultra-low-threshold terahertz polariton lasing, voltage-controlled modulators and frequency filters, and ultra-sensitive chemical and biological sensing.
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26
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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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27
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A continued fraction based approach for the Two-photon Quantum Rabi Model. Sci Rep 2019; 9:4156. [PMID: 30858449 PMCID: PMC6411859 DOI: 10.1038/s41598-019-39281-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 12/20/2018] [Indexed: 11/08/2022] Open
Abstract
We study the Two Photon Quantum Rabi Model by way of its spectral functions and survival probabilities. This approach allows numerical precision with large truncation numbers, and thus exploration of the spectral collapse. We provide independent checks and calibration of the numerical results by studying an exactly solvable case and comparing the essential qualitative structure of the spectral functions. We stress that the large time limit of the survival probability provides us with an indicator of spectral collapse, and propose a technique for the detection of this signal in the current and upcoming quantum simulations of the model.
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28
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Gao W, Kono J. Science and applications of wafer-scale crystalline carbon nanotube films prepared through controlled vacuum filtration. ROYAL SOCIETY OPEN SCIENCE 2019; 6:181605. [PMID: 31032018 PMCID: PMC6458426 DOI: 10.1098/rsos.181605] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 02/06/2019] [Indexed: 05/26/2023]
Abstract
Carbon nanotubes (CNTs) make an ideal one-dimensional (1D) material platform for the exploration of novel physical phenomena under extremely strong quantum confinement. The 1D character of electrons, phonons and excitons in individual CNTs features extraordinary electronic, thermal and optical properties. Since their discovery in 1991, they have been continuing to attract interest in various disciplines, including chemistry, materials science, physics and engineering. However, the macroscopic manifestation of 1D properties is still limited, despite significant efforts for decades. Recently, a controlled vacuum filtration method has been developed for the preparation of wafer-scale films of crystalline chirality-enriched CNTs, and such films have enabled exciting new fundamental studies and applications. In this review, we will first discuss the controlled vacuum filtration technique, and then summarize recent discoveries in optical spectroscopy studies and optoelectronic device applications using films prepared by this technique.
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Affiliation(s)
- Weilu Gao
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA
| | - Junichiro Kono
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA
- Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX 77005, USA
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29
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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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30
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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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31
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Malekakhlagh M, Rodriguez AW. Quantum Rabi Model with Two-Photon Relaxation. PHYSICAL REVIEW LETTERS 2019; 122:043601. [PMID: 30768294 DOI: 10.1103/physrevlett.122.043601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Indexed: 06/09/2023]
Abstract
We study a cavity-QED setup consisting of a two-level system coupled to a single cavity mode with two-photon relaxation. The system dynamics is modeled via a Lindblad master equation consisting of the Rabi Hamiltonian and a two-photon dissipator. We show that an even-photon relaxation preserves the Z_{2} symmetry of the Rabi model, and provide a framework to study the corresponding non-Hermitian dynamics in the number-parity basis. We discuss the role of different terms in the two-photon dissipator and show how one can extend existing results for the closed Rabi spectrum to the open case. Furthermore, we characterize the role of the Z_{2} symmetry in the excitation-relaxation dynamics of the system as a function of light-matter coupling. Importantly, we observe that initial states with even-odd parity manifest qualitatively distinct transient and steady state behaviors, contrary to the Hermitian dynamics that is only sensitive to whether or not the initial state is parity invariant. Moreover, the parity-sensitive dynamical behavior is not a creature of ultrastrong coupling and is present even at weak coupling values.
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Affiliation(s)
- Moein Malekakhlagh
- Department of Electrical Engineering, Princeton University, New Jersey 08544, USA
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32
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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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33
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Di Stefano O, Kockum AF, Ridolfo A, Savasta S, Nori F. Photodetection probability in quantum systems with arbitrarily strong light-matter interaction. Sci Rep 2018; 8:17825. [PMID: 30546126 PMCID: PMC6292927 DOI: 10.1038/s41598-018-36056-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 11/14/2018] [Indexed: 12/02/2022] Open
Abstract
Cavity-QED systems have recently reached a regime where the light-matter interaction strength amounts to a non-negligible fraction of the resonance frequencies of the bare subsystems. In this regime, it is known that the usual normal-order correlation functions for the cavity-photon operators fail to describe both the rate and the statistics of emitted photons. Following Glauber’s original approach, we derive a simple and general quantum theory of photodetection, valid for arbitrary light-matter interaction strengths. Our derivation uses Fermi’s golden rule, together with an expansion of system operators in the eigenbasis of the interacting light-matter system, to arrive at the correct photodetection probabilities. We consider both narrow- and wide-band photodetectors. Our description is also valid for point-like detectors placed inside the optical cavity. As an application, we propose a gedanken experiment confirming the virtual nature of the bare excitations that enrich the ground state of the quantum Rabi model.
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Affiliation(s)
- Omar Di Stefano
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama, 351-0198, Japan
| | - Anton Frisk Kockum
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama, 351-0198, Japan.,Wallenberg Centre for Quantum Technology, Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Alessandro Ridolfo
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama, 351-0198, Japan
| | - Salvatore Savasta
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama, 351-0198, Japan. .,MIFT - Dipartimento di Scienze Matematiche e Informatiche Scienze Fisiche e Scienze della Terra, Università di Messina, I-98166, Messina, Italy.
| | - Franco Nori
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama, 351-0198, Japan.,Physics Department, The University of Michigan, Ann Arbor, Michigan, 48109-1040, USA
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34
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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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35
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Fan JW, Xu J, Cheng MT, Yang Y. Vacuum induced transparency in metamaterials. OPTICS EXPRESS 2018; 26:19498-19512. [PMID: 30114121 DOI: 10.1364/oe.26.019498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 07/10/2018] [Indexed: 06/08/2023]
Abstract
For the cavity-based electromagnetically induced transparent (EIT), as the coherent driving field is enhanced by the optical cavity, the weak probe field can propagate through the atomic ensemble without absorption even if the driving field is weak. The extreme case of vacuum in the cavity is called "vacuum-induced transparency" (VIT) to distinguish it from the cavity EIT. Here we construct a new kind of cavity made of Metamaterials, i.e. ε-negative (EN) and μ-negative (MN) slabs, and study the VIT phenomena of the atomic ensemble doped within it. When the impedances of the MN and EN slabs are matched to each other and the dissipation of the material is small, it behaves as a surface plasmon cavity with a huge Q factor. And the VIT phenomenon in this cavity appears. By adjusting the position of atoms, the coupling strength between the atom and the structure could be changed. Two kinds of extremes of VIT, the coherent population trapping (CPT) and the Autler-Townes splitting (ATS), can be achieved in this system easily. Our proposal could be used in the realization of ultra-strong coupling and integrated devices on quantum memory or optical switch.
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36
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Bennett K, Kowalewski M, Mukamel S. Novel photochemistry of molecular polaritons in optical cavities. Faraday Discuss 2018; 194:259-282. [PMID: 27711849 DOI: 10.1039/c6fd00095a] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Violations of the Born-Oppenheimer approximation (BOA) and the consequent nonadiabatic dynamics have long been an object of intense study. Recently, such dynamics have been induced via strong coupling of the molecule to a high-amplitude (spatially confined) mode of the electromagnetic field in optical cavities. However, the effects of a cavity on a pre-existing avoided crossing or conical intersection are relatively unexplored. The dynamics of molecules dressed by cavity modes are usually calculated by invoking the rotating wave approximation (RWA), which greatly simplifies the calculation but breaks down when the cavity mode frequency is higher than the relevant material frequencies. We develop a protocol for computing curve crossing dynamics in an optical cavity by exploiting a recently-developed method of solving the quantum Rabi model without invoking the RWA. The method is demonstrated for sodium iodide.
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Affiliation(s)
- Kochise Bennett
- Chemistry Department, University of California, Irvine, California 92697-2025, USA.
| | - Markus Kowalewski
- Chemistry Department, University of California, Irvine, California 92697-2025, USA.
| | - Shaul Mukamel
- Chemistry Department, University of California, Irvine, California 92697-2025, USA.
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37
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Resolution of superluminal signalling in non-perturbative cavity quantum electrodynamics. Nat Commun 2018; 9:1924. [PMID: 29765054 PMCID: PMC5954151 DOI: 10.1038/s41467-018-04339-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 04/23/2018] [Indexed: 12/04/2022] Open
Abstract
Recent technological developments have made it increasingly easy to access the non-perturbative regimes of cavity quantum electrodynamics known as ultrastrong or deep strong coupling, where the light–matter coupling becomes comparable to the bare modal frequencies. In this work, we address the adequacy of the broadly used single-mode cavity approximation to describe such regimes. We demonstrate that, in the non-perturbative light–matter coupling regimes, the single-mode models become unphysical, allowing for superluminal signalling. Moreover, considering the specific example of the quantum Rabi model, we show that the multi-mode description of the electromagnetic field, necessary to account for light propagation at finite speed, yields physical observables that differ radically from their single-mode counterparts already for moderate values of the coupling. Our multi-mode analysis also reveals phenomena of fundamental interest on the dynamics of the intracavity electric field, where a free photonic wavefront and a bound state of virtual photons are shown to coexist. Quantum Rabi model is a standard tool for describing cavity quantum electrodynamics, but the potential shortcomings of its single-mode version are usually neglected. Here, the authors show that, in the ultrastrong coupling regime, a multimode Rabi model is mandatory in order to avoid unphysical results.
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38
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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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39
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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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40
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Keller J, Scalari G, Cibella S, Maissen C, Appugliese F, Giovine E, Leoni R, Beck M, Faist J. Few-Electron Ultrastrong Light-Matter Coupling at 300 GHz with Nanogap Hybrid LC Microcavities. NANO LETTERS 2017; 17:7410-7415. [PMID: 29172537 DOI: 10.1021/acs.nanolett.7b03228] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Ultrastrong light-matter coupling allows the exploration of new states of matter through the interaction of strong vacuum fields with huge electronic dipoles. By using hybrid dipole antenna-split ring resonator-based cavities with extremely small effective mode volumes Veff/λ03 ≃ 6 × 10-10 and surfaces Seff/λ02 ≃ 3.5 × 10-7, we probe the ultrastrong light-matter coupling at 300 GHz to less than 100 electrons located in the last occupied Landau level of a high mobility two-dimensional electron gas, measuring a normalized coupling ratio of ΩR/ωc = 0.36. Effects of the extremely reduced cavity dimensions are observed as the light-matter coupled system is better described by an effective mass heavier than the uncoupled one. These results open the way to ultrastrong coupling at the single-electron level in two-dimensional electron systems.
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Affiliation(s)
- Janine Keller
- ETH Zürich, Institute of Quantum Electronics , Auguste-Piccard-Hof 1, Zürich 8093, Switzerland
| | - Giacomo Scalari
- ETH Zürich, Institute of Quantum Electronics , Auguste-Piccard-Hof 1, Zürich 8093, Switzerland
| | - Sara Cibella
- Istituto di Fotonica e Nanotecnologie (IFN), CNR , via Cineto Romano 42, 00156 Rome, Italy
| | - Curdin Maissen
- ETH Zürich, Institute of Quantum Electronics , Auguste-Piccard-Hof 1, Zürich 8093, Switzerland
| | - Felice Appugliese
- ETH Zürich, Institute of Quantum Electronics , Auguste-Piccard-Hof 1, Zürich 8093, Switzerland
| | - Ennio Giovine
- Istituto di Fotonica e Nanotecnologie (IFN), CNR , via Cineto Romano 42, 00156 Rome, Italy
| | - Roberto Leoni
- Istituto di Fotonica e Nanotecnologie (IFN), CNR , via Cineto Romano 42, 00156 Rome, Italy
| | - Mattias Beck
- ETH Zürich, Institute of Quantum Electronics , Auguste-Piccard-Hof 1, Zürich 8093, Switzerland
| | - Jérôme Faist
- ETH Zürich, Institute of Quantum Electronics , Auguste-Piccard-Hof 1, Zürich 8093, Switzerland
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41
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Bin Q, Lü XY, Bin SW, Zhu GL, Wu Y. Single-photon-induced two qubits excitation without breaking parity symmetry. OPTICS EXPRESS 2017; 25:31718-31729. [PMID: 29245843 DOI: 10.1364/oe.25.031718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 11/28/2017] [Indexed: 06/07/2023]
Abstract
We investigate theoretically the model of two "qubits" system (one qubit having an auxiliary level) interacting with a single-mode resonator in the ultrastrong coupling regime. We show that a single photon could simultaneously excite two qubits without breaking the parity symmetry of system by properly encoding the excited states of qubits. The optimal parameter regime for achieving high probability approaching one is identified in the case of ignoring the system dissipation. Moreover, using experimentally feasible parameters, we also analyze the dissipation dynamics of the system, and present the realization of two-qubit excitation induced by single-photon. This work offers an alternative approach to realize the single-photon-induced two qubits excitation, which should advance the development of single-photon quantum technologies and have potential applications in quantum information science.
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42
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Liu M, Chesi S, Ying ZJ, Chen X, Luo HG, Lin HQ. Universal Scaling and Critical Exponents of the Anisotropic Quantum Rabi Model. PHYSICAL REVIEW LETTERS 2017; 119:220601. [PMID: 29286818 DOI: 10.1103/physrevlett.119.220601] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Indexed: 06/07/2023]
Abstract
We investigate the quantum phase transition of the anisotropic quantum Rabi model, in which the rotating and counterrotating terms are allowed to have different coupling strengths. The model interpolates between two known limits with distinct universal properties. Through a combination of analytic and numerical approaches, we extract the phase diagram, scaling functions, and critical exponents, which determine the universality class at finite anisotropy (identical to the isotropic limit). We also reveal other interesting features, including a superradiance-induced freezing of the effective mass and discontinuous scaling functions in the Jaynes-Cummings limit. Our findings are extended to the few-body quantum phase transitions with N>1 spins, where we expose the same effective parameters, scaling properties, and phase diagram. Thus, a stronger form of universality is established, valid from N=1 up to the thermodynamic limit.
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Affiliation(s)
- Maoxin Liu
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Stefano Chesi
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Zu-Jian Ying
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Xiaosong Chen
- Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong-Gang Luo
- Beijing Computational Science Research Center, Beijing 100193, China
- Center for Interdisciplinary Studies and Key Laboratory for Magnetism and Magnetic Materials of the MoE, Lanzhou University, Lanzhou 730000, China
| | - Hai-Qing Lin
- Beijing Computational Science Research Center, Beijing 100193, China
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43
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Li H, Shen HZ, Wu SL, Yi XX. Shortcuts to adiabaticity in non-Hermitian quantum systems without rotating-wave approximation. OPTICS EXPRESS 2017; 25:30135-30148. [PMID: 29221047 DOI: 10.1364/oe.25.030135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 11/01/2017] [Indexed: 06/07/2023]
Abstract
The technique of shortcuts to adiabaticity (STA) has attracted broad attention due to their possible applications in quantum information processing and quantum control. However, most studies published so far have been only focused on Hermitian systems under the rotating-wave approximation (RWA). In this paper, we propose a modified shortcuts to adiabaticity technique to realize population transfer for a non-Hermitian system without RWA. We work out an exact expression for the control function and present examples consisting of two-and three-level systems with decay to show the theory. The results suggest that the shortcuts to adiabaticity technique presented here is robust for fast passages. We also find that the decay has small effect on the population transfer in the three-level system. To shed more light on the physics behind this result, we reduce the quantum three-level system to an effective two-level one with large detunings. The shortcuts to adiabaticity technique of effective two-level system is studied. Thereby the high-fidelity population transfer can be implemented in non-Hermitian systems by our method, and it works even without RWA.
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44
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Experimentally simulating the dynamics of quantum light and matter at deep-strong coupling. Nat Commun 2017; 8:1715. [PMID: 29167425 PMCID: PMC5700074 DOI: 10.1038/s41467-017-01061-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Accepted: 08/15/2017] [Indexed: 11/08/2022] Open
Abstract
The quantum Rabi model describing the fundamental interaction between light and matter is a cornerstone of quantum physics. It predicts exotic phenomena like quantum phase transitions and ground-state entanglement in ultrastrong and deep-strong coupling regimes, where coupling strengths are comparable to or larger than subsystem energies. Demonstrating dynamics remains an outstanding challenge, the few experiments reaching these regimes being limited to spectroscopy. Here, we employ a circuit quantum electrodynamics chip with moderate coupling between a resonator and transmon qubit to realise accurate digital quantum simulation of deep-strong coupling dynamics. We advance the state of the art in solid-state digital quantum simulation by using up to 90 second-order Trotter steps and probing both subsystems in a combined Hilbert space dimension of ∼80, demonstrating characteristic Schrödinger-cat-like entanglement and large photon build-up. Our approach will enable exploration of extreme coupling regimes and quantum phase transitions, and demonstrates a clear first step towards larger complexities such as in the Dicke model.
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45
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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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46
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Analog quantum simulation of the Rabi model in the ultra-strong coupling regime. Nat Commun 2017; 8:779. [PMID: 28974675 PMCID: PMC5626763 DOI: 10.1038/s41467-017-00894-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 08/03/2017] [Indexed: 11/20/2022] Open
Abstract
The quantum Rabi model describes the fundamental mechanism of light-matter interaction. It consists of a two-level atom or qubit coupled to a quantized harmonic mode via a transversal interaction. In the weak coupling regime, it reduces to the well-known Jaynes–Cummings model by applying a rotating wave approximation. The rotating wave approximation breaks down in the ultra-strong coupling regime, where the effective coupling strength g is comparable to the energy ω of the bosonic mode, and remarkable features in the system dynamics are revealed. Here we demonstrate an analog quantum simulation of an effective quantum Rabi model in the ultra-strong coupling regime, achieving a relative coupling ratio of g/ω ~ 0.6. The quantum hardware of the simulator is a superconducting circuit embedded in a cQED setup. We observe fast and periodic quantum state collapses and revivals of the initial qubit state, being the most distinct signature of the synthesized model. An analog quantum simulation scheme has been explored with a quantum hardware based on a superconducting circuit. Here the authors investigate the time evolution of the quantum Rabi model at ultra-strong coupling conditions, which is synthesized by slowing down the system dynamics in an effective frame.
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47
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Wendin G. Quantum information processing with superconducting circuits: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:106001. [PMID: 28682303 DOI: 10.1088/1361-6633/aa7e1a] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
During the last ten years, superconducting circuits have passed from being interesting physical devices to becoming contenders for near-future useful and scalable quantum information processing (QIP). Advanced quantum simulation experiments have been shown with up to nine qubits, while a demonstration of quantum supremacy with fifty qubits is anticipated in just a few years. Quantum supremacy means that the quantum system can no longer be simulated by the most powerful classical supercomputers. Integrated classical-quantum computing systems are already emerging that can be used for software development and experimentation, even via web interfaces. Therefore, the time is ripe for describing some of the recent development of superconducting devices, systems and applications. As such, the discussion of superconducting qubits and circuits is limited to devices that are proven useful for current or near future applications. Consequently, the centre of interest is the practical applications of QIP, such as computation and simulation in Physics and Chemistry.
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Affiliation(s)
- G Wendin
- Department of Microtechnology and Nanoscience-MC2, Chalmers University of Technology, SE-41296 Gothenburg, Sweden
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Park K, Marek P, Filip R. Qubit-mediated deterministic nonlinear gates for quantum oscillators. Sci Rep 2017; 7:11536. [PMID: 28912504 PMCID: PMC5599512 DOI: 10.1038/s41598-017-11353-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 08/22/2017] [Indexed: 11/09/2022] Open
Abstract
Quantum nonlinear operations for harmonic oscillator systems play a key role in the development of analog quantum simulators and computers. Since strong highly nonlinear operations are often unavailable in the existing physical systems, it is a common practice to approximate them by using conditional measurement-induced methods. The conditional approach has several drawbacks, the most severe of which is the exponentially decreasing success rate of the strong and complex nonlinear operations. We show that by using a suitable two level system sequentially interacting with the oscillator, it is possible to resolve these issues and implement a nonlinear operation both nearly deterministically and nearly perfectly. We explicitly demonstrate the approach by constructing self-Kerr and cross-Kerr couplings in a realistic situation, which require a feasible dispersive coupling between the two-level system and the oscillator.
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Affiliation(s)
- Kimin Park
- Department of Optics, Palacký University, 17. listopadu 1192/12, 77146, Olomouc, Czech Republic.
| | - Petr Marek
- Department of Optics, Palacký University, 17. listopadu 1192/12, 77146, Olomouc, Czech Republic
| | - Radim Filip
- Department of Optics, Palacký University, 17. listopadu 1192/12, 77146, Olomouc, Czech Republic
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Plankensteiner D, Sommer C, Ritsch H, Genes C. Cavity Antiresonance Spectroscopy of Dipole Coupled Subradiant Arrays. PHYSICAL REVIEW LETTERS 2017; 119:093601. [PMID: 28949558 DOI: 10.1103/physrevlett.119.093601] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Indexed: 06/07/2023]
Abstract
An array of N closely spaced dipole coupled quantum emitters exhibits super- and subradiance with characteristic tailorable spatial radiation patterns. Optimizing the emitter geometry and distance with respect to the spatial profile of a near resonant optical cavity mode allows us to increase the ratio between light scattering into the cavity mode and free space emission by several orders of magnitude. This leads to distinct scaling of the collective coherent emitter-field coupling vs the free space decay as a function of the emitter number. In particular, for subradiant states, the effective cooperativity increases much faster than the typical linear ∝N scaling for independent emitters. This extraordinary collective enhancement is manifested both in the amplitude and the phase profile of narrow collective antiresonances appearing at the cavity output port in transmission spectroscopy.
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Affiliation(s)
- David Plankensteiner
- Institut für Theoretische Physik, Universität Innsbruck, Technikerstraße 21a, A-6020 Innsbruck, Austria
| | - Christian Sommer
- Max Planck Institute for the Science of Light, Staudtstraße 2, D-91058 Erlangen, Germany
| | - Helmut Ritsch
- Institut für Theoretische Physik, Universität Innsbruck, Technikerstraße 21a, A-6020 Innsbruck, Austria
| | - Claudiu Genes
- Max Planck Institute for the Science of Light, Staudtstraße 2, D-91058 Erlangen, Germany
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Barberena D, Lamata L, Solano E. Dispersive Regimes of the Dicke Model. Sci Rep 2017; 7:8774. [PMID: 28821802 PMCID: PMC5562824 DOI: 10.1038/s41598-017-09110-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 07/20/2017] [Indexed: 11/08/2022] Open
Abstract
We study two dispersive regimes of the Dicke model in the dynamics of N two-level atoms interacting with a bosonic mode for long interaction times. Firstly, we analyze the model for the regime in which the qubit frequencies are equal and smaller than the mode frequency, and for values of the coupling strength similar or larger than the mode frequency, namely, the deep strong coupling regime. Secondly, we address an interaction that is dependent on the photon number, where the coupling strength is comparable to the geometric mean of the qubit and mode frequencies. We show that the associated dynamics is analytically tractable and provide useful frameworks with which to analyze the system behavior. In the deep strong coupling regime, we unveil the structure of unexpected resonances for specific values of the coupling, present for N ≥ 2, and in the photon-number-dependent regime we demonstrate that all the nontrivial dynamical behavior occurs in the atomic degrees of freedom for a given Fock state. We verify these assertions with numerical simulations of the qubit population and photon-statistic dynamics.
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Affiliation(s)
- Diego Barberena
- Departamento de Ciencias, Sección Física, Pontificia Universidad Católica del Perú, Apartado, 1761, Lima, Peru
| | - Lucas Lamata
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080, Bilbao, Spain.
| | - Enrique Solano
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080, Bilbao, Spain
- IKERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, 48013, Bilbao, Spain
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