1
|
Bond LJ, Safavi-Naini A, Minář J. Fast Quantum State Preparation and Bath Dynamics Using Non-Gaussian Variational Ansatz and Quantum Optimal Control. PHYSICAL REVIEW LETTERS 2024; 132:170401. [PMID: 38728702 DOI: 10.1103/physrevlett.132.170401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 01/15/2024] [Accepted: 03/25/2024] [Indexed: 05/12/2024]
Abstract
Fast preparation of quantum many-body states is essential for myriad quantum algorithms and metrological applications. Here, we develop a new pathway for fast, nonadiabatic preparation of quantum many-body states that combines quantum optimal control with a variational Ansatz based on non-Gaussian states. We demonstrate our approach on the spin-boson model, a single spin interacting with the bath. We use a multipolaron Ansatz to prepare near-critical ground states. For one mode, we achieve a reduction in infidelity of up to ≈60 (≈10) times compared to linear (optimized local adiabatic) ramps; for many modes, we achieve a reduction in infidelity of up to ≈5 times compared to nonadiabatic linear ramps. Further, we show that the typical control quantity, the leakage from the variational manifold, provides only a loose bound on the state's fidelity. Instead, in analogy to the bond dimension of matrix product states, we suggest a controlled convergence criterion based on the number of polarons. Finally, motivated by the possibility of realizations in trapped ions, we study the dynamics of a system with bath properties going beyond the paradigm of (sub- and/or super-) Ohmic couplings.
Collapse
Affiliation(s)
- Liam J Bond
- Institute for Theoretical Physics, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- QuSoft, Science Park 123, 1098 XG Amsterdam, The Netherlands
| | - Arghavan Safavi-Naini
- Institute for Theoretical Physics, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- QuSoft, Science Park 123, 1098 XG Amsterdam, The Netherlands
| | - Jiří Minář
- Institute for Theoretical Physics, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- QuSoft, Science Park 123, 1098 XG Amsterdam, The Netherlands
- CWI, Science Park 904, 1098 XH Amsterdam, The Netherlands
| |
Collapse
|
2
|
Kala V, Filip R, Marek P. Cubic nonlinear squeezing and its decoherence. OPTICS EXPRESS 2022; 30:31456-31471. [PMID: 36242226 DOI: 10.1364/oe.464759] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 07/17/2022] [Indexed: 06/16/2023]
Abstract
Squeezed states of the harmonic oscillator are a common resource in applications of quantum technology. If the noise is suppressed in a nonlinear combination of quadrature operators below threshold for all possible up-to-quadratic Hamiltonians, the quantum states are non-Gaussian and we refer to the noise reduction as nonlinear squeezing. Non-Gaussian aspects of quantum states are often more vulnerable to decoherence due to imperfections appearing in realistic experimental implementations. Therefore, a stability of nonlinear squeezing is essential. We analyze the behavior of quantum states with cubic nonlinear squeezing under loss and dephasing. The properties of nonlinear squeezed states depend on their initial parameters which can be optimized and adjusted to achieve the maximal robustness for the potential applications.
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
MacDonell RJ, Dickerson CE, Birch CJT, Kumar A, Edmunds CL, Biercuk MJ, Hempel C, Kassal I. Analog quantum simulation of chemical dynamics. Chem Sci 2021; 12:9794-9805. [PMID: 34349953 PMCID: PMC8293981 DOI: 10.1039/d1sc02142g] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/14/2021] [Indexed: 11/21/2022] Open
Abstract
Ultrafast chemical reactions are difficult to simulate because they involve entangled, many-body wavefunctions whose computational complexity grows rapidly with molecular size. In photochemistry, the breakdown of the Born-Oppenheimer approximation further complicates the problem by entangling nuclear and electronic degrees of freedom. Here, we show that analog quantum simulators can efficiently simulate molecular dynamics using commonly available bosonic modes to represent molecular vibrations. Our approach can be implemented in any device with a qudit controllably coupled to bosonic oscillators and with quantum hardware resources that scale linearly with molecular size, and offers significant resource savings compared to digital quantum simulation algorithms. Advantages of our approach include a time resolution orders of magnitude better than ultrafast spectroscopy, the ability to simulate large molecules with limited hardware using a Suzuki-Trotter expansion, and the ability to implement realistic system-bath interactions with only one additional interaction per mode. Our approach can be implemented with current technology; e.g., the conical intersection in pyrazine can be simulated using a single trapped ion. Therefore, we expect our method will enable classically intractable chemical dynamics simulations in the near term.
Collapse
Affiliation(s)
- Ryan J MacDonell
- School of Chemistry, University of Sydney NSW 2006 Australia
- University of Sydney Nano Institute, University of Sydney NSW 2006 Australia
| | - Claire E Dickerson
- School of Chemistry, University of Sydney NSW 2006 Australia
- School of Physics, University of Sydney NSW 2006 Australia
- ARC Centre of Excellence for Engineered Quantum Systems, University of Sydney NSW 2006 Australia
- University of Sydney Nano Institute, University of Sydney NSW 2006 Australia
| | - Clare J T Birch
- School of Chemistry, University of Sydney NSW 2006 Australia
- University of Sydney Nano Institute, University of Sydney NSW 2006 Australia
| | - Alok Kumar
- Department of Chemistry, Indian Institute of Technology Bombay Mumbai 400076 India
| | - Claire L Edmunds
- School of Physics, University of Sydney NSW 2006 Australia
- ARC Centre of Excellence for Engineered Quantum Systems, University of Sydney NSW 2006 Australia
| | - Michael J Biercuk
- School of Physics, University of Sydney NSW 2006 Australia
- ARC Centre of Excellence for Engineered Quantum Systems, University of Sydney NSW 2006 Australia
| | - Cornelius Hempel
- School of Physics, University of Sydney NSW 2006 Australia
- ARC Centre of Excellence for Engineered Quantum Systems, University of Sydney NSW 2006 Australia
- University of Sydney Nano Institute, University of Sydney NSW 2006 Australia
| | - Ivan Kassal
- School of Chemistry, University of Sydney NSW 2006 Australia
- University of Sydney Nano Institute, University of Sydney NSW 2006 Australia
| |
Collapse
|
5
|
Bräuer Š, Marek P. Generation of quantum states with nonlinear squeezing by Kerr nonlinearity. OPTICS EXPRESS 2021; 29:22648-22658. [PMID: 34266023 DOI: 10.1364/oe.427637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/16/2021] [Indexed: 06/13/2023]
Abstract
In quantum optics, squeezing corresponds to the process in which fluctuations of a quadrature operator are reduced below the shot noise limit. In turn, nonlinear squeezing can be defined as reduction of fluctuations related to nonlinear combination of quadrature operators. Quantum states with nonlinear squeezing are a necessary resource for deterministic implementation of high-order quadrature phase gates that are, in turn, sufficient for advanced quantum information processing. We demonstrate that this class of states can be deterministically prepared by employing a single self-Kerr gate accompanied by suitable Gaussian processing. The required Kerr coupling depends on the energy of the initial system and can be made arbitrarily small. We also employ numerical simulations to analyze the effects of imperfections and to show to which extent can they be neglected.
Collapse
|
6
|
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.
Collapse
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
| |
Collapse
|
7
|
Cai ML, Liu ZD, Zhao WD, Wu YK, Mei QX, Jiang Y, He L, Zhang X, Zhou ZC, Duan LM. Observation of a quantum phase transition in the quantum Rabi model with a single trapped ion. Nat Commun 2021; 12:1126. [PMID: 33602942 PMCID: PMC7893029 DOI: 10.1038/s41467-021-21425-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 01/22/2021] [Indexed: 11/30/2022] Open
Abstract
Quantum phase transitions (QPTs) are usually associated with many-body systems in the thermodynamic limit when their ground states show abrupt changes at zero temperature with variation of a parameter in the Hamiltonian. Recently it has been realized that a QPT can also occur in a system composed of only a two-level atom and a single-mode bosonic field, described by the quantum Rabi model (QRM). Here we report an experimental demonstration of a QPT in the QRM using a 171Yb+ ion in a Paul trap. We measure the spin-up state population and the average phonon number of the ion as two order parameters and observe clear evidence of the phase transition via adiabatic tuning of the coupling between the ion and its spatial motion. An experimental probe of the phase transition in a fundamental quantum optics model without imposing the thermodynamic limit opens up a window for controlled study of QPTs and quantum critical phenomena. Quantum phase transition occurs in many-body systems with abrupt changes in the ground state around zero temperature. Here the authors report signatures of quantum phase transition in single trapped ion that can be described using quantum Rabi model.
Collapse
Affiliation(s)
- M-L Cai
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, PR China
| | - Z-D Liu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, PR China
| | - W-D Zhao
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, PR China
| | - Y-K Wu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, PR China
| | - Q-X Mei
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, PR China
| | - Y Jiang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, PR China
| | - L He
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, PR China
| | - X Zhang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, PR China.,Department of Physics, Renmin University, Beijing, PR China
| | - Z-C Zhou
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, PR China.,Beijing Academy of Quantum Information Sciences, Beijing, PR China
| | - L-M Duan
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, PR China.
| |
Collapse
|
8
|
Reiter F, Nguyen TL, Home JP, Yelin SF. Cooperative Breakdown of the Oscillator Blockade in the Dicke Model. PHYSICAL REVIEW LETTERS 2020; 125:233602. [PMID: 33337189 DOI: 10.1103/physrevlett.125.233602] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 03/30/2020] [Accepted: 10/02/2020] [Indexed: 06/12/2023]
Abstract
The Dicke model, which describes the coupling of an ensemble of spins to a harmonic oscillator, is known for its superradiant phase transition, which can both be observed in the ground state in a purely Hamiltonian setting, as well as in the steady state of an open-system Dicke model with dissipation. We demonstrate that, in addition, the dissipative Dicke model can undergo a second phase transition to a nonstationary phase, characterized by unlimited heating of the harmonic oscillator. Identifying the mechanism of the phase transition and deriving the scaling of the critical coupling with the system size we conclude that the novel phase transition can be understood as a cooperative breakdown of the oscillator blockade which otherwise prevents higher excitation of the system. We discuss an implementation with trapped ions and investigate the role of cooling, by which the breakdown can be suppressed.
Collapse
Affiliation(s)
- Florentin Reiter
- Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138, USA
- Institute for Quantum Electronics, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| | - Thanh Long Nguyen
- Institute for Quantum Electronics, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| | - Jonathan P Home
- Institute for Quantum Electronics, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| | - Susanne F Yelin
- Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138, USA
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, USA
| |
Collapse
|
9
|
Johnsson MT, Mukty NR, Burgarth D, Volz T, Brennen GK. Geometric Pathway to Scalable Quantum Sensing. PHYSICAL REVIEW LETTERS 2020; 125:190403. [PMID: 33216597 DOI: 10.1103/physrevlett.125.190403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 07/23/2020] [Accepted: 10/08/2020] [Indexed: 06/11/2023]
Abstract
Entangled resources enable quantum sensing that achieves Heisenberg scaling, a quadratic improvement on the standard quantum limit, but preparing large N spin entangled states is challenging in the presence of decoherence. We present a quantum control strategy using highly nonlinear geometric phase gates which can be used for generic state or unitary synthesis on the Dicke subspace with O(N) or O(N^{2}) gates, respectively. The method uses a dispersive coupling of the spins to a common bosonic mode and does not require addressability, special detunings, or interactions between the spins. By using amplitude amplification our control sequence for preparing states ideal for metrology can be significantly simplified to O(N^{5/4}) geometric phase gates with action angles O(1/N) that are more robust to mode decay. The geometrically closed path of the control operations ensures the gates are insensitive to the initial state of the mode and the sequence has built-in dynamical decoupling providing resilience to dephasing errors.
Collapse
Affiliation(s)
- Mattias T Johnsson
- Center for Engineered Quantum Systems, Department of Physics and Astronomy, Macquarie University, North Ryde, 2109 New South Wales, Australia
| | - Nabomita Roy Mukty
- Center for Engineered Quantum Systems, Department of Physics and Astronomy, Macquarie University, North Ryde, 2109 New South Wales, Australia
| | - Daniel Burgarth
- Center for Engineered Quantum Systems, Department of Physics and Astronomy, Macquarie University, North Ryde, 2109 New South Wales, Australia
| | - Thomas Volz
- Center for Engineered Quantum Systems, Department of Physics and Astronomy, Macquarie University, North Ryde, 2109 New South Wales, Australia
| | - Gavin K Brennen
- Center for Engineered Quantum Systems, Department of Physics and Astronomy, Macquarie University, North Ryde, 2109 New South Wales, Australia
| |
Collapse
|
10
|
Zhu HJ, Xu K, Zhang GF, Liu WM. Finite-Component Multicriticality at the Superradiant Quantum Phase Transition. PHYSICAL REVIEW LETTERS 2020; 125:050402. [PMID: 32794842 DOI: 10.1103/physrevlett.125.050402] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 07/08/2020] [Indexed: 06/11/2023]
Abstract
We demonstrate the existence of finite-component multicriticality in a qubit-boson model where biased qubits collectively coupled to a single-mode bosonic field. The interplay between biases and boson-qubit coupling produces a rich phase diagram which shows multiple superradiant phases and phase boundaries of different orders. In particular, multiple phases become indistinguishable in appropriate bias configurations, which is the signature of multicriticality. A series of universality classes characterizing these multicritical points are identified. Moreover, we present a trapped-ion realization with the potential to explore multicritical phenomena experimentally using a small number of ions. The results open a novel way to probe multicritical universality classes in experiments.
Collapse
Affiliation(s)
- Han-Jie Zhu
- Key Laboratory of Micro-Nano Measurement-Manipulation and Physics (Ministry of Education), School of Physics, Beihang University, Xueyuan Road No. 37, Beijing 100191, China
| | - Kai Xu
- Key Laboratory of Micro-Nano Measurement-Manipulation and Physics (Ministry of Education), School of Physics, Beihang University, Xueyuan Road No. 37, Beijing 100191, China
| | - Guo-Feng Zhang
- Key Laboratory of Micro-Nano Measurement-Manipulation and Physics (Ministry of Education), School of Physics, Beihang University, Xueyuan Road No. 37, Beijing 100191, China
| | - Wu-Ming Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| |
Collapse
|
11
|
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.
Collapse
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.
| |
Collapse
|
12
|
Abah O, Puebla R, Paternostro M. Quantum State Engineering by Shortcuts to Adiabaticity in Interacting Spin-Boson Systems. PHYSICAL REVIEW LETTERS 2020; 124:180401. [PMID: 32441978 DOI: 10.1103/physrevlett.124.180401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/20/2020] [Indexed: 06/11/2023]
Abstract
We present a fast and robust framework to prepare nonclassical states of a bosonic mode exploiting a coherent exchange of excitations with a two-level system ruled by a Jaynes-Cummings interaction mechanism. Our protocol, which is built on shortcuts to adiabaticity, allows for the generation of arbitrary Fock states of the bosonic mode, as well as coherent quantum superpositions of a Schrödinger cat-like form. In addition, we show how to obtain a class of photon-shifted states where the vacuum population is removed, a result akin to photon addition, but displaying more nonclassicality than standard photon-added states. Owing to the ubiquity of the spin-boson interaction that we consider, our proposal is amenable for implementations in state-of-the-art experiments.
Collapse
Affiliation(s)
- Obinna Abah
- Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, United Kingdom
| | - Ricardo Puebla
- Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, United Kingdom
| | - Mauro Paternostro
- Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, United Kingdom
| |
Collapse
|
13
|
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.
Collapse
|
14
|
Spin-Boson Model as A Simulator of Non-Markovian Multiphoton Jaynes-Cummings Models. Symmetry (Basel) 2019. [DOI: 10.3390/sym11050695] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The paradigmatic spin-boson model considers a spin degree of freedom interacting with an environment typically constituted by a continuum of bosonic modes. This ubiquitous model is of relevance in a number of physical systems where, in general, one has neither control over the bosonic modes, nor the ability to tune distinct interaction mechanisms. Despite this apparent lack of control, we present a suitable transformation that approximately maps the spin-boson dynamics into that of a tunable multiphoton Jaynes-Cummings model undergoing dissipation. Interestingly, the latter model describes the coherent interaction between a spin and a single bosonic mode via the simultaneous exchange of n bosons per spin excitation. Resorting to the so-called reaction coordinate method, we identify a relevant collective bosonic mode in the environment, which is then used to generate multiphoton interactions following the proposed theoretical framework. Moreover, we show that spin-boson models featuring structured environments can lead to non-Markovian multiphoton Jaynes-Cummings dynamics. We discuss the validity of the proposed method depending on the parameters and analyse its performance, which is supported by numerical simulations. In this manner, the spin-boson model serves as a good analogue quantum simulator for the inspection and realization of multiphoton Jaynes-Cummings models, as well as the interplay of non-Markovian effects and, thus, as a simulator of light-matter systems with tunable interaction mechanisms.
Collapse
|
15
|
Wang G, Xiao R, Shen HZ, Sun C, Xue K. Simulating Anisotropic quantum Rabi model via frequency modulation. Sci Rep 2019; 9:4569. [PMID: 30872697 PMCID: PMC6418198 DOI: 10.1038/s41598-019-40899-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 02/25/2019] [Indexed: 11/09/2022] Open
Abstract
Anisotropic quantum Rabi model is a generalization of quantum Rabi model, which allows its rotating and counter-rotating terms to have two different coupling constants. It provides us with a fundamental model to understand various physical features concerning quantum optics, solid-state physics, and mesoscopic physics. In this paper, we propose an experimental feasible scheme to implement anisotropic quantum Rabi model in a circuit quantum electrodynamics system via periodic frequency modulation. An effective Hamiltonian describing the tunable anisotropic quantum Rabi model can be derived from a qubit-resonator coupling system modulated by two periodic driving fields. All effective parameters of the simulated system can be adjusted by tuning the initial phases, the frequencies and the amplitudes of the driving fields. We show that the periodic driving is able to drive a coupled system in dispersive regime to ultrastrong coupling regime, and even deep-strong coupling regime. The derived effective Hamiltonian allows us to obtain pure rotating term and counter-rotating term. Numerical simulation shows that such effective Hamiltonian is valid in ultrastrong coupling regime, and stronger coupling regime. Moreover, our scheme can be generalized to the multi-qubit case. We also give some applications of the simulated system to the Schrödinger cat states and quantum gate generalization. The presented proposal will pave a way to further study the stronger anisotropic Rabi model whose coupling strength is far away from ultrastrong coupling and deep-strong coupling regimes in quantum optics.
Collapse
Affiliation(s)
- Gangcheng Wang
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China.
| | - Ruoqi Xiao
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China
| | - H Z Shen
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China.
| | - Chunfang Sun
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China
| | - Kang Xue
- Center for Quantum Sciences and School of Physics, Northeast Normal University, Changchun, 130024, China.
| |
Collapse
|
16
|
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.
Collapse
|
17
|
Huerta Alderete C, Morales Rodríguez MP, Rodríguez-Lara BM. Engineering SU(1, 1) ⊗ SU(1, 1) vibrational states. Sci Rep 2019; 9:2734. [PMID: 30804414 PMCID: PMC6389955 DOI: 10.1038/s41598-019-39481-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/22/2019] [Indexed: 11/25/2022] Open
Abstract
We propose an ideal scheme for preparing vibrational SU(1, 1) ⊗ SU(1, 1) states in a two-dimensional ion trap using red and blue second sideband resolved driving of two orthogonal vibrational modes. Symmetric and asymmetric driving provide two regimes to realize quantum state engineering of the vibrational modes. In one regime, we show that time evolution synthesizes so-called SU(1, 1) Perelomov coherent states, that is separable squeezed states and their superposition too. The other regime allows engineering of lossless 50/50 SU(2) beam splitter states that are entangled states. These ideal dynamics are reversible, thus, the non-classical and entangled states produced by our schemes might be used as resources for interferometry.
Collapse
Affiliation(s)
- C Huerta Alderete
- Instituto Nacional de Astrofísica, Óptica y Electrónica, Calle Luis Enrique Erro No. 1, Sta. Ma. Tonantzintla, Pue. CP 72840, Mexico
| | - M P Morales Rodríguez
- Programa Delfín, Verano de la Investigación Científica - Instituto Nacional de Astrofísica, Óptica y Electrónica, Calle Luis Enrique Erro No. 1, Sta. Ma. Tonantzintla, Pue. CP 72840, Mexico
| | - B M Rodríguez-Lara
- Instituto Nacional de Astrofísica, Óptica y Electrónica, Calle Luis Enrique Erro No. 1, Sta. Ma. Tonantzintla, Pue. CP 72840, Mexico. .,Tecnologico de Monterrey, Escuela de Ingeniería y Ciencias, Ave. Eugenio Garza Sada 2501, Monterrey, N.L., 64849, Mexico.
| |
Collapse
|
18
|
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.
Collapse
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.
| |
Collapse
|
19
|
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.
Collapse
Affiliation(s)
- Moein Malekakhlagh
- Department of Electrical Engineering, Princeton University, New Jersey 08544, USA
| | | |
Collapse
|
20
|
Safavi-Naini A, Lewis-Swan RJ, Bohnet JG, Gärttner M, Gilmore KA, Jordan JE, Cohn J, Freericks JK, Rey AM, Bollinger JJ. Verification of a Many-Ion Simulator of the Dicke Model Through Slow Quenches across a Phase Transition. PHYSICAL REVIEW LETTERS 2018; 121:040503. [PMID: 30095931 DOI: 10.1103/physrevlett.121.040503] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 06/26/2018] [Indexed: 06/08/2023]
Abstract
We use a self-assembled two-dimensional Coulomb crystal of ∼70 ions in the presence of an external transverse field to engineer a simulator of the Dicke Hamiltonian, an iconic model in quantum optics which features a quantum phase transition between a superradiant (ferromagnetic) and a normal (paramagnetic) phase. We experimentally implement slow quenches across the quantum critical point and benchmark the dynamics and the performance of the simulator through extensive theory-experiment comparisons which show excellent agreement. The implementation of the Dicke model in fully controllable trapped ion arrays can open a path for the generation of highly entangled states useful for enhanced metrology and the observation of scrambling and quantum chaos in a many-body system.
Collapse
Affiliation(s)
- A Safavi-Naini
- JILA, NIST and University of Colorado, 440 UCB, Boulder, Colorado 80309, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
| | - R J Lewis-Swan
- JILA, NIST and University of Colorado, 440 UCB, Boulder, Colorado 80309, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
| | | | - M Gärttner
- JILA, NIST and University of Colorado, 440 UCB, Boulder, Colorado 80309, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
- Kirchhoff-Institut für Physik, Universität Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | | | | | - J Cohn
- Department of Physics, Georgetown University, Washington, DC 20057, USA
| | - J K Freericks
- Department of Physics, Georgetown University, Washington, DC 20057, USA
| | - A M Rey
- JILA, NIST and University of Colorado, 440 UCB, Boulder, Colorado 80309, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
| | | |
Collapse
|
21
|
Pedernales JS, Beau M, Pittman SM, Egusquiza IL, Lamata L, Solano E, Del Campo A. Dirac Equation in (1+1)-Dimensional Curved Spacetime and the Multiphoton Quantum Rabi Model. PHYSICAL REVIEW LETTERS 2018; 120:160403. [PMID: 29756911 DOI: 10.1103/physrevlett.120.160403] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 01/25/2018] [Indexed: 06/08/2023]
Abstract
We introduce an exact mapping between the Dirac equation in (1+1)-dimensional curved spacetime (DCS) and a multiphoton quantum Rabi model (QRM). A background of a (1+1)-dimensional black hole requires a QRM with one- and two-photon terms that can be implemented in a trapped ion for the quantum simulation of Dirac particles in curved spacetime. We illustrate our proposal with a numerical analysis of the free fall of a Dirac particle into a (1+1)-dimensional black hole, and find that the Zitterbewegung effect, measurable via the oscillatory trajectory of the Dirac particle, persists in the presence of gravity. From the duality between the squeezing term in the multiphoton QRM and the metric coupling in the DCS, we show that gravity generates squeezing of the Dirac particle wave function.
Collapse
Affiliation(s)
- J S Pedernales
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain
- Institute for Theoretical Physics and IQST, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany
| | - M Beau
- Department of Physics, University of Massachusetts, Boston, Massachusetts 02125, USA
| | - S M Pittman
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - I L Egusquiza
- Department of Theoretical Physics and History of Science, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain
| | - L Lamata
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain
| | - E 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
- Department of Physics, Shanghai University, 200444 Shanghai, China
| | - A Del Campo
- Department of Physics, University of Massachusetts, Boston, Massachusetts 02125, USA
| |
Collapse
|
22
|
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.
Collapse
|
23
|
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.
Collapse
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
| |
Collapse
|
24
|
Joshi C, Irish EK, Spiller TP. Qubit-flip-induced cavity mode squeezing in the strong dispersive regime of the quantum Rabi model. Sci Rep 2017; 7:45587. [PMID: 28358025 PMCID: PMC5372368 DOI: 10.1038/srep45587] [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: 12/30/2016] [Accepted: 02/28/2017] [Indexed: 11/09/2022] Open
Abstract
Squeezed states of light are a set of nonclassical states in which the quantum fluctuations of one quadrature component are reduced below the standard quantum limit. With less noise than the best stabilised laser sources, squeezed light is a key resource in the field of quantum technologies and has already improved sensing capabilities in areas ranging from gravitational wave detection to biomedical applications. In this work we propose a novel technique for generating squeezed states of a confined light field strongly coupled to a two-level system, or qubit, in the dispersive regime. Utilising the dispersive energy shift caused by the interaction, control of the qubit state produces a time-dependent change in the frequency of the light field. An appropriately timed sequence of sudden frequency changes reduces the quantum noise fluctuations in one quadrature of the field well below the standard quantum limit. The degree of squeezing and the time of generation are directly controlled by the number of frequency shifts applied. Even in the presence of realistic noise and imperfections, our protocol promises to be capable of generating a useful degree of squeezing with present experimental capabilities.
Collapse
Affiliation(s)
- Chaitanya Joshi
- Department of Physics and York Centre for Quantum Technologies, University of York, Heslington, York, YO10 5DD, UK
| | - Elinor K Irish
- Physics and Astronomy, University of Southampton, Highfield, Southampton, SO17 1BJ, UK
| | - Timothy P Spiller
- Department of Physics and York Centre for Quantum Technologies, University of York, Heslington, York, YO10 5DD, UK
| |
Collapse
|
25
|
Lamata L. Digital-analog quantum simulation of generalized Dicke models with superconducting circuits. Sci Rep 2017; 7:43768. [PMID: 28256559 PMCID: PMC5335609 DOI: 10.1038/srep43768] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 01/27/2017] [Indexed: 11/19/2022] Open
Abstract
We propose a digital-analog quantum simulation of generalized Dicke models with superconducting circuits, including Fermi- Bose condensates, biased and pulsed Dicke models, for all regimes of light-matter coupling. We encode these classes of problems in a set of superconducting qubits coupled with a bosonic mode implemented by a transmission line resonator. Via digital-analog techniques, an efficient quantum simulation can be performed in state-of-the-art circuit quantum electrodynamics platforms, by suitable decomposition into analog qubit-bosonic blocks and collective single-qubit pulses through digital steps. Moreover, just a single global analog block would be needed during the whole protocol in most of the cases, superimposed with fast periodic pulses to rotate and detune the qubits. Therefore, a large number of digital steps may be attained with this approach, providing a reduced digital error. Additionally, the number of gates per digital step does not grow with the number of qubits, rendering the simulation efficient. This strategy paves the way for the scalable digital-analog quantum simulation of many-body dynamics involving bosonic modes and spin degrees of freedom with superconducting circuits.
Collapse
Affiliation(s)
- Lucas Lamata
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain
| |
Collapse
|
26
|
Puebla R, Hwang MJ, Casanova J, Plenio MB. Probing the Dynamics of a Superradiant Quantum Phase Transition with a Single Trapped Ion. PHYSICAL REVIEW LETTERS 2017; 118:073001. [PMID: 28256873 DOI: 10.1103/physrevlett.118.073001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Indexed: 06/06/2023]
Abstract
We demonstrate that the quantum phase transition (QPT) of the Rabi model and critical dynamics near the QPT can be probed in the setup of a single trapped ion. We first demonstrate that there exists equilibrium and nonequilibrium scaling functions of the Rabi model by finding a proper rescaling of the system parameters and observables, and show that those scaling functions are representative of the universality class to which the Rabi model belongs. We then propose a scheme that can faithfully realize the Rabi model in the limit of a large ratio of the effective atomic transition frequency to the oscillator frequency using a single trapped ion and, therefore, the QPT. It is demonstrated that the predicted universal functions can indeed be observed based on our scheme. Finally, the effects of realistic noise sources on probing the universal functions in experiments are examined.
Collapse
Affiliation(s)
- Ricardo Puebla
- Institut für Theoretische Physik and IQST, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany
| | - Myung-Joong Hwang
- Institut für Theoretische Physik and IQST, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany
| | - Jorge Casanova
- Institut für Theoretische Physik and IQST, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany
| | - Martin B Plenio
- Institut für Theoretische Physik and IQST, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany
| |
Collapse
|
27
|
Abstract
We show how to produce a fast quantum Rabi model with trapped ions. Its importance resides not only in the acceleration of the phenomena that may be achieved with these systems, from quantum gates to the generation of nonclassical states of the vibrational motion of the ion, but also in reducing unwanted effects such as the decay of coherences that may appear in such systems.
Collapse
|
28
|
Parity Deformed Jaynes-Cummings Model: "Robust Maximally Entangled States". Sci Rep 2016; 6:38069. [PMID: 27917882 PMCID: PMC5137026 DOI: 10.1038/srep38069] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 10/28/2016] [Indexed: 11/25/2022] Open
Abstract
The parity-deformations of the quantum harmonic oscillator are used to describe the generalized Jaynes-Cummings model based on the λ-analog of the Heisenberg algebra. The behavior is interestingly that of a coupled system comprising a two-level atom and a cavity field assisted by a continuous external classical field. The dynamical characters of the system is explored under the influence of the external field. In particular, we analytically study the generation of robust and maximally entangled states formed by a two-level atom trapped in a lossy cavity interacting with an external centrifugal field. We investigate the influence of deformation and detuning parameters on the degree of the quantum entanglement and the atomic population inversion. Under the condition of a linear interaction controlled by an external field, the maximally entangled states may emerge periodically along with time evolution. In the dissipation regime, the entanglement of the parity deformed JCM are preserved more with the increase of the deformation parameter, i.e. the stronger external field induces better degree of entanglement.
Collapse
|
29
|
Hwang MJ, Plenio MB. Quantum Phase Transition in the Finite Jaynes-Cummings Lattice Systems. PHYSICAL REVIEW LETTERS 2016; 117:123602. [PMID: 27689271 DOI: 10.1103/physrevlett.117.123602] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Indexed: 06/06/2023]
Abstract
Phase transitions are commonly held to occur only in the thermodynamical limit of a large number of system components. Here, we exemplify at the hand of the exactly solvable Jaynes-Cummings (JC) model and its generalization to finite JC lattices that finite component systems of coupled spins and bosons may exhibit quantum phase transitions (QPTs). For the JC model we find a continuous symmetry-breaking QPT, a photonic condensate with a macroscopic occupation as the ground state, and a Goldstone mode as a low-energy excitation. For the two site JC lattice we show analytically that it undergoes a Mott-insulator to superfluid QPT. We identify as the underlying principle of the emergence of finite system QPTs the combination of increasing atomic energy and increasing interaction strength between the atom and the bosonic mode, which allows for the exploration of an increasingly large portion of the infinite dimensional Hilbert space of the bosonic mode. This suggests that finite system phase transitions will be present in a broad range of physical systems.
Collapse
Affiliation(s)
- Myung-Joong Hwang
- Institut für Theoretische Physik and IQST, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany
| | - Martin B Plenio
- Institut für Theoretische Physik and IQST, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany
| |
Collapse
|
30
|
Ivanov PA, Vitanov NV, Singer K. High-precision force sensing using a single trapped ion. Sci Rep 2016; 6:28078. [PMID: 27306426 PMCID: PMC4910112 DOI: 10.1038/srep28078] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 05/26/2016] [Indexed: 11/09/2022] Open
Abstract
We introduce quantum sensing schemes for measuring very weak forces with a single trapped ion. They use the spin-motional coupling induced by the laser-ion interaction to transfer the relevant force information to the spin-degree of freedom. Therefore, the force estimation is carried out simply by observing the Ramsey-type oscillations of the ion spin states. Three quantum probes are considered, which are represented by systems obeying the Jaynes-Cummings, quantum Rabi (in 1D) and Jahn-Teller (in 2D) models. By using dynamical decoupling schemes in the Jaynes-Cummings and Jahn-Teller models, our force sensing protocols can be made robust to the spin dephasing caused by the thermal and magnetic field fluctuations. In the quantum-Rabi probe, the residual spin-phonon coupling vanishes, which makes this sensing protocol naturally robust to thermally-induced spin dephasing. We show that the proposed techniques can be used to sense the axial and transverse components of the force with a sensitivity beyond the range, i.e. in the (xennonewton, 10(-27)). The Jahn-Teller protocol, in particular, can be used to implement a two-channel vector spectrum analyzer for measuring ultra-low voltages.
Collapse
Affiliation(s)
- Peter A. Ivanov
- Department of Physics, St. Kliment Ohridski University of Sofia, James Bourchier 5 blvd, 1164 Sofia, Bulgaria
| | - Nikolay V. Vitanov
- Department of Physics, St. Kliment Ohridski University of Sofia, James Bourchier 5 blvd, 1164 Sofia, Bulgaria
| | - Kilian Singer
- Experimentalphysik I, Universität Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel, Germany
| |
Collapse
|