1
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Joshi LK, Franke J, Rath A, Ares F, Murciano S, Kranzl F, Blatt R, Zoller P, Vermersch B, Calabrese P, Roos CF, Joshi MK. Observing the Quantum Mpemba Effect in Quantum Simulations. PHYSICAL REVIEW LETTERS 2024; 133:010402. [PMID: 39042798 DOI: 10.1103/physrevlett.133.010402] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 03/29/2024] [Indexed: 07/25/2024]
Abstract
The nonequilibrium physics of many-body quantum systems harbors various unconventional phenomena. In this Letter, we experimentally investigate one of the most puzzling of these phenomena-the quantum Mpemba effect, where a tilted ferromagnet restores its symmetry more rapidly when it is farther from the symmetric state compared to when it is closer. We present the first experimental evidence of the occurrence of this effect in a trapped-ion quantum simulator. The symmetry breaking and restoration are monitored through entanglement asymmetry, probed via randomized measurements, and postprocessed using the classical shadows technique. Our findings are further substantiated by measuring the Frobenius distance between the experimental state and the stationary thermal symmetric theoretical state, offering direct evidence of subsystem thermalization.
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Affiliation(s)
- Lata Kh Joshi
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
- University of Innsbruck, Institute for Theoretical Physics, Technikerstraße 21a, 6020 Innsbruck, Austria
- SISSA and INFN, via Bonomea 265, 34136 Trieste, Italy
| | - Johannes Franke
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
- University of Innsbruck, Institute for Experimental Physics, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Aniket Rath
- Univiversité Grenoble Alpes, CNRS, LPMMC, 38000 Grenoble, France
| | | | - Sara Murciano
- Walter Burke Institute for Theoretical Physics, and Department of Physics and IQIM, Caltech, Pasadena, California 91125, USA
| | - Florian Kranzl
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
- University of Innsbruck, Institute for Experimental Physics, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Rainer Blatt
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
- University of Innsbruck, Institute for Experimental Physics, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Peter Zoller
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
- University of Innsbruck, Institute for Theoretical Physics, Technikerstraße 21a, 6020 Innsbruck, Austria
| | - Benoît Vermersch
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
- University of Innsbruck, Institute for Theoretical Physics, Technikerstraße 21a, 6020 Innsbruck, Austria
- Univiversité Grenoble Alpes, CNRS, LPMMC, 38000 Grenoble, France
| | - Pasquale Calabrese
- SISSA and INFN, via Bonomea 265, 34136 Trieste, Italy
- International Centre for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy
| | - Christian F Roos
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
- University of Innsbruck, Institute for Experimental Physics, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Manoj K Joshi
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
- University of Innsbruck, Institute for Experimental Physics, Technikerstraße 25, 6020 Innsbruck, Austria
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2
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Diba O, Miller HJD, Iles-Smith J, Nazir A. Quantum Work Statistics at Strong Reservoir Coupling. PHYSICAL REVIEW LETTERS 2024; 132:190401. [PMID: 38804950 DOI: 10.1103/physrevlett.132.190401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 03/25/2024] [Indexed: 05/29/2024]
Abstract
Determining the statistics of work done on a quantum system while strongly coupled to a reservoir is a formidable task, requiring the calculation of the full eigenspectrum of the combined system and reservoir. Here, we show that this issue can be circumvented by using a polaron transformation that maps the system into a new frame where weak-coupling theory can be applied. Crucially, this polaron approach reproduces the Jarzynski fluctuation theorem, thus ensuring consistency with the laws of stochastic thermodynamics. We apply our formalism to a system driven across the Landau-Zener transition, where we identify clear signatures in the work distribution arising from a non-negligible coupling to the environment. Our results provide a new method for studying the stochastic thermodynamics of driven quantum systems beyond Markovian, weak-coupling regimes.
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Affiliation(s)
- Owen Diba
- Department of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Harry J D Miller
- Department of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Jake Iles-Smith
- Department of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Ahsan Nazir
- Department of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, United Kingdom
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3
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Kang M, Nuomin H, Chowdhury SN, Yuly JL, Sun K, Whitlow J, Valdiviezo J, Zhang Z, Zhang P, Beratan DN, Brown KR. Seeking a quantum advantage with trapped-ion quantum simulations of condensed-phase chemical dynamics. Nat Rev Chem 2024; 8:340-358. [PMID: 38641733 DOI: 10.1038/s41570-024-00595-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2024] [Indexed: 04/21/2024]
Abstract
Simulating the quantum dynamics of molecules in the condensed phase represents a longstanding challenge in chemistry. Trapped-ion quantum systems may serve as a platform for the analog-quantum simulation of chemical dynamics that is beyond the reach of current classical-digital simulation. To identify a 'quantum advantage' for these simulations, performance analysis of both analog-quantum simulation on noisy hardware and classical-digital algorithms is needed. In this Review, we make a comparison between a noisy analog trapped-ion simulator and a few choice classical-digital methods on simulating the dynamics of a model molecular Hamiltonian with linear vibronic coupling. We describe several simple Hamiltonians that are commonly used to model molecular systems, which can be simulated with existing or emerging trapped-ion hardware. These Hamiltonians may serve as stepping stones towards the use of trapped-ion simulators for systems beyond the reach of classical-digital methods. Finally, we identify dynamical regimes in which classical-digital simulations seem to have the weakest performance with respect to analog-quantum simulations. These regimes may provide the lowest hanging fruit to make the most of potential quantum advantages.
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Affiliation(s)
- Mingyu Kang
- Duke Quantum Center, Duke University, Durham, NC, USA.
- Department of Physics, Duke University, Durham, NC, USA.
| | - Hanggai Nuomin
- Department of Chemistry, Duke University, Durham, NC, USA
| | | | - Jonathon L Yuly
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Ke Sun
- Duke Quantum Center, Duke University, Durham, NC, USA
- Department of Physics, Duke University, Durham, NC, USA
| | - Jacob Whitlow
- Duke Quantum Center, Duke University, Durham, NC, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA
| | - Jesús Valdiviezo
- Kenneth S. Pitzer Theory Center, University of California, Berkeley, CA, USA
- Department of Chemistry, University of California, Berkeley, CA, USA
- Departamento de Ciencias, Sección Química, Pontificia Universidad Católica del Perú, Lima, Peru
| | - Zhendian Zhang
- Department of Chemistry, Duke University, Durham, NC, USA
| | - Peng Zhang
- Department of Chemistry, Duke University, Durham, NC, USA
| | - David N Beratan
- Department of Physics, Duke University, Durham, NC, USA.
- Department of Chemistry, Duke University, Durham, NC, USA.
- Department of Biochemistry, Duke University, Durham, NC, USA.
| | - Kenneth R Brown
- Duke Quantum Center, Duke University, Durham, NC, USA.
- Department of Physics, Duke University, Durham, NC, USA.
- Department of Chemistry, Duke University, Durham, NC, USA.
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA.
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4
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Ferreira J, Jin T, Mannhart J, Giamarchi T, Filippone M. Transport and Nonreciprocity in Monitored Quantum Devices: An Exact Study. PHYSICAL REVIEW LETTERS 2024; 132:136301. [PMID: 38613271 DOI: 10.1103/physrevlett.132.136301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 01/03/2024] [Accepted: 01/25/2024] [Indexed: 04/14/2024]
Abstract
We study noninteracting fermionic systems undergoing continuous monitoring and driven by biased reservoirs. Averaging over the measurement outcomes, we derive exact formulas for the particle and heat flows in the system. We show that these currents feature competing elastic and inelastic components, which depend nontrivially on the monitoring strength γ. We highlight that monitor-induced inelastic processes lead to nonreciprocal currents, allowing one to extract work from measurements without active feedback control. We illustrate our formalism with two distinct monitoring schemes providing measurement-induced power or cooling. Optimal performances are found for values of the monitoring strength γ, which are hard to address with perturbative approaches.
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Affiliation(s)
- João Ferreira
- Department of Quantum Matter Physics, École de Physique University of Geneva, 1211 Geneva, Switzerland
| | - Tony Jin
- Department of Quantum Matter Physics, École de Physique University of Geneva, 1211 Geneva, Switzerland
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Jochen Mannhart
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - Thierry Giamarchi
- Department of Quantum Matter Physics, École de Physique University of Geneva, 1211 Geneva, Switzerland
| | - Michele Filippone
- IRIG-MEM-L_Sim, Université Grenoble Alpes, CEA, Grenoble INP, Grenoble 38000, France
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5
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Alterman S, Berman J, Strauch FW. Optimal conditions for environment-assisted quantum transport on the fully connected network. Phys Rev E 2024; 109:014310. [PMID: 38366420 DOI: 10.1103/physreve.109.014310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 12/19/2023] [Indexed: 02/18/2024]
Abstract
We present a theoretical analysis of the efficiency and rate of excitation transport on a network described by a complete graph in which every site is connected to every other. The long-time transport properties are analytically calculated for networks of arbitrary size that are symmetric except for the trapping site, start with a range of initial states, and are subject to dephasing and excitation decay. Conditions for which dephasing increases transport are identified, and optimal conditions are found for various physical parameters. The optimal conditions demonstrate robustness and a convergence of timescales previously observed in the context of light-harvesting complexes.
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Affiliation(s)
- Sam Alterman
- Department of Physics, Williams College, Williamstown, Massachusetts 01267, USA
| | - Justin Berman
- Department of Physics, Williams College, Williamstown, Massachusetts 01267, USA
| | - Frederick W Strauch
- Department of Physics, Williams College, Williamstown, Massachusetts 01267, USA
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6
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Sarkar A, Sen S, Kumar S. Spectral crossovers in non-Hermitian spin chains: Comparison with random matrix theory. Phys Rev E 2023; 108:054210. [PMID: 38115444 DOI: 10.1103/physreve.108.054210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 10/10/2023] [Indexed: 12/21/2023]
Abstract
We present a systematic investigation of the short-range spectral fluctuation properties of three non-Hermitian spin-chain Hamiltonians using complex spacing ratios (CSRs). Specifically, we focus on the non-Hermitian variants of the standard one-dimensional anisotropic XY model having intrinsic rotation-time (RT) symmetry that has been explored analytically by Zhang and Song [Phys. Rev. A 87, 012114 (2013)1050-294710.1103/PhysRevA.87.012114]. The corresponding Hermitian counterpart is also exactly solvable and has been widely employed as a toy model in several condensed matter physics problems. We show that the presence of a random field along the x direction together with the one along the z direction facilitates integrability and RT-symmetry breaking, leading to the emergence of quantum chaotic behavior. This is evidenced by a spectral crossover closely resembling the transition from Poissonian to Ginibre unitary ensemble (GinUE) statistics of random matrix theory. Additionally, we consider two phenomenological random matrix models in this paper to examine 1D Poisson to GinUE and 2D Poisson to GinUE crossovers and the associated signatures in CSRs. Here 1D and 2D Poisson correspond to real and complex uncorrelated levels, respectively. These crossovers reasonably capture spectral fluctuations observed in the spin-chain systems within a certain range of parameters.
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Affiliation(s)
- Ayana Sarkar
- Department of Physics, Shiv Nadar Institution of Eminence, Gautam Buddha Nagar, Uttar Pradesh-201314, India
| | - Sunidhi Sen
- Department of Physics, Shiv Nadar Institution of Eminence, Gautam Buddha Nagar, Uttar Pradesh-201314, India
| | - Santosh Kumar
- Department of Physics, Shiv Nadar Institution of Eminence, Gautam Buddha Nagar, Uttar Pradesh-201314, India
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7
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Zerah Harush E, Dubi Y. Signature of Quantum Coherence in the Exciton Energy Pathways of the LH2 Photosynthetic Complex. ACS OMEGA 2023; 8:38871-38878. [PMID: 37901547 PMCID: PMC10601065 DOI: 10.1021/acsomega.3c02676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 06/15/2023] [Indexed: 10/31/2023]
Abstract
Unraveling the energy transfer pathways in photosynthetic complexes is an important step toward understanding their structure-function interplay. Here, we use an open quantum systems approach to investigate energy transfer within the LH2 photosynthetic apparatus and its dependence on environmental conditions. We find that energy transfer pathways strongly depend on the environment-induced dephasing time. A comparison between the computational results and experiments performed on similar systems demonstrates that quantum coherences are present in these systems under physiological conditions and have an important role in shaping the energy transfer pathways. Moreover, our calculations indicate that relatively simple spectroscopy experiments can be used to detect traces of quantum coherence. Finally, our results suggest that quantum coherence may play a role in photosynthesis, but not in enhancing the efficiency as was previously suggested.
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Affiliation(s)
- Elinor Zerah Harush
- Department of Chemistry and
Ilse Katz Center for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Yonatan Dubi
- Department of Chemistry and
Ilse Katz Center for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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8
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Catalano AG, Mattiotti F, Dubail J, Hagenmüller D, Prosen T, Franchini F, Pupillo G. Anomalous Diffusion in the Long-Range Haken-Strobl-Reineker Model. PHYSICAL REVIEW LETTERS 2023; 131:053401. [PMID: 37595217 DOI: 10.1103/physrevlett.131.053401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 07/17/2023] [Indexed: 08/20/2023]
Abstract
We analyze the propagation of excitons in a d-dimensional lattice with power-law hopping ∝1/r^{α} in the presence of dephasing, described by a generalized Haken-Strobl-Reineker model. We show that in the strong dephasing (quantum Zeno) regime the dynamics is described by a classical master equation for an exclusion process with long jumps. In this limit, we analytically compute the spatial distribution, whose shape changes at a critical value of the decay exponent α_{cr}=(d+2)/2. The exciton always diffuses anomalously: a superdiffusive motion is associated to a Lévy stable distribution with long-range algebraic tails for α≤α_{cr}, while for α>α_{cr} the distribution corresponds to a surprising mixed Gaussian profile with long-range algebraic tails, leading to the coexistence of short-range diffusion and long-range Lévy flights. In the many-exciton case, we demonstrate that, starting from a domain-wall exciton profile, algebraic tails appear in the distributions for any α, which affects thermalization: the longer the hopping range, the faster equilibrium is reached. Our results are directly relevant to experiments with cold trapped ions, Rydberg atoms, and supramolecular dye aggregates. They provide a way to realize an exclusion process with long jumps experimentally.
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Affiliation(s)
- A G Catalano
- University of Strasbourg and CNRS, CESQ and ISIS (UMR 7006), aQCess, 67000 Strasbourg, France
- Institut Ruđer Bošković, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - F Mattiotti
- University of Strasbourg and CNRS, CESQ and ISIS (UMR 7006), aQCess, 67000 Strasbourg, France
| | - J Dubail
- University of Strasbourg and CNRS, CESQ and ISIS (UMR 7006), aQCess, 67000 Strasbourg, France
- Université de Lorraine and CNRS, LPCT (UMR 7019), 54000 Nancy, France
| | - D Hagenmüller
- University of Strasbourg and CNRS, CESQ and ISIS (UMR 7006), aQCess, 67000 Strasbourg, France
| | - T Prosen
- Faculty for Mathematics and Physics, University of Ljubljana, Jadranska ulica 19, 1000 Ljubljana, Slovenia
| | - F Franchini
- Institut Ruđer Bošković, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - G Pupillo
- University of Strasbourg and CNRS, CESQ and ISIS (UMR 7006), aQCess, 67000 Strasbourg, France
- Institut Universitaire de France (IUF), 75000 Paris, France
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9
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Sauerwein N, Orsi F, Uhrich P, Bandyopadhyay S, Mattiotti F, Cantat-Moltrecht T, Pupillo G, Hauke P, Brantut JP. Engineering random spin models with atoms in a high-finesse cavity. NATURE PHYSICS 2023; 19:1128-1134. [PMID: 37575364 PMCID: PMC10415180 DOI: 10.1038/s41567-023-02033-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 03/23/2023] [Indexed: 08/15/2023]
Abstract
All-to-all interacting, disordered quantum many-body models have a wide range of applications across disciplines, from spin glasses in condensed-matter physics over holographic duality in high-energy physics to annealing algorithms in quantum computing. Typically, these models are abstractions that do not find unambiguous physical realizations in nature. Here we realize an all-to-all interacting, disordered spin system by subjecting an atomic cloud in a cavity to a controllable light shift. Adjusting the detuning between atom resonance and cavity mode, we can tune between disordered versions of a central-mode model and a Lipkin-Meshkov-Glick model. By spectroscopically probing the low-energy excitations of the system, we explore the competition of interactions with disorder across a broad parameter range. We show how disorder in the central-mode model breaks the strong collective coupling, making the dark-state manifold cross over to a random distribution of weakly mixed light-matter, 'grey', states. In the Lipkin-Meshkov-Glick model, the ferromagnetic finite-sized ground state evolves towards a paramagnet as disorder is increased. In that regime, semi-localized eigenstates emerge, as we observe by extracting bounds on the participation ratio. These results present substantial steps towards freely programmable cavity-mediated interactions for the design of arbitrary spin Hamiltonians.
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Affiliation(s)
- Nick Sauerwein
- Institute of Physics and Center for Quantum Science and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Francesca Orsi
- Institute of Physics and Center for Quantum Science and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Philipp Uhrich
- Pitaevskii BEC Center, CNR-INO and Dipartimento di Fisica, Università di Trento, Trento, Italy
- INFN-TIFPA, Trento Institute for Fundamental Physics and Applications, Trento, Italy
| | - Soumik Bandyopadhyay
- Pitaevskii BEC Center, CNR-INO and Dipartimento di Fisica, Università di Trento, Trento, Italy
- INFN-TIFPA, Trento Institute for Fundamental Physics and Applications, Trento, Italy
| | - Francesco Mattiotti
- University of Strasbourg and CNRS, CESQ and ISIS (UMR 7006), aQCess, Strasbourg, France
| | - Tigrane Cantat-Moltrecht
- Institute of Physics and Center for Quantum Science and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Guido Pupillo
- University of Strasbourg and CNRS, CESQ and ISIS (UMR 7006), aQCess, Strasbourg, France
| | - Philipp Hauke
- Pitaevskii BEC Center, CNR-INO and Dipartimento di Fisica, Università di Trento, Trento, Italy
- INFN-TIFPA, Trento Institute for Fundamental Physics and Applications, Trento, Italy
| | - Jean-Philippe Brantut
- Institute of Physics and Center for Quantum Science and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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10
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Madhu AK, Melnikov AA, Fedichkin LE, Alodjants AP, Lee RK. Quantum walk processes in quantum devices. Heliyon 2023; 9:e13416. [PMID: 36895413 PMCID: PMC9988498 DOI: 10.1016/j.heliyon.2023.e13416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/07/2022] [Accepted: 01/30/2023] [Indexed: 02/10/2023] Open
Abstract
Simulation and programming of current quantum computers as Noisy Intermediate-Scale Quantum (NISQ) devices represent a hot topic at the border of current physical and information sciences. The quantum walk process represents a basic subroutine in many quantum algorithms and plays an important role in studying physical phenomena. Simulating quantum walk processes is computationally challenging for classical processors. With an increasing improvement in qubits fidelity and qubits number in a single register, there is a potential to improve quantum walks simulations substantially. However, efficient ways to simulate quantum walks in qubit registers still have to be explored. Here, we explore the relationship between quantum walk on graphs and quantum circuits. Firstly, we discuss ways to obtain graphs provided quantum circuit. We then explore techniques to represent quantum walk on a graph as a quantum circuit. Specifically, we study hypercube graphs and arbitrary graphs. Our approach to studying the relationship between graphs and quantum circuits paves way for the efficient implementation of quantum walks algorithms on quantum computers.
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Affiliation(s)
| | - Alexey A. Melnikov
- Valiev Institute of Physics and Technology, Russian Academy of Sciences, 117218 Moscow, Russia
- Corresponding author.
| | - Leonid E. Fedichkin
- Valiev Institute of Physics and Technology, Russian Academy of Sciences, 117218 Moscow, Russia
- Department of Theoretical Physics, Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
| | - Alexander P. Alodjants
- ITMO University, 197101 St. Petersburg, Russia
- Quantum Light Engineering Laboratory, Institute of Natural and Exact Sciences, South Ural State University (SUSU), 454080 Chelyabinsk, Russia
| | - Ray-Kuang Lee
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei 10617, Taiwan
- Center for Quantum Technology, Hsinchu 30013, Taiwan
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11
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Schmolke F, Lutz E. Noise-Induced Quantum Synchronization. PHYSICAL REVIEW LETTERS 2022; 129:250601. [PMID: 36608236 DOI: 10.1103/physrevlett.129.250601] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 11/17/2022] [Indexed: 06/17/2023]
Abstract
Synchronization is a widespread phenomenon in science and technology. Here, we study noise-induced synchronization in a quantum spin chain subjected to local Gaussian white noise. We demonstrate stable (anti)synchronization between the endpoint magnetizations of a quantum XY model with transverse field of arbitrary length. Remarkably, we show that noise applied to a single spin suffices to reach stable (anti)synchronization, and find that the two synchronized end spins are entangled. We additionally determine the optimal noise amplitude that leads to the fastest synchronization along the chain, and further compare the optimal synchronization speed to the fundamental Lieb-Robinson bound for information propagation.
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Affiliation(s)
- Finn Schmolke
- Institute for Theoretical Physics I, University of Stuttgart, D-70550 Stuttgart, Germany
| | - Eric Lutz
- Institute for Theoretical Physics I, University of Stuttgart, D-70550 Stuttgart, Germany
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12
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Suntijitrungruang O, Lakronwat J, Uthailiang T, Pongkitiwanichakul P, Boonchui S. Simulation of the sensing mechanism in quantum dot gas sensor by quantum light harvesting approach. Front Chem 2022; 10:1036197. [PMID: 36324518 PMCID: PMC9618855 DOI: 10.3389/fchem.2022.1036197] [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: 09/04/2022] [Accepted: 09/28/2022] [Indexed: 11/26/2022] Open
Abstract
Quantum dot (QD) gas sensors are one of the most useful nanotechnologies applied to protect people from unnecessary harm. This work theoretically explores the mechanism in QD gas sensors in order to advance the prudent design of relevant products. The theoretical model employed in this research is similar to the process in plants’ photosynthesis, referred to as charge separation of light harvesting. In this work, we investigate the details of energy transport in QD gas sensors carried by electrons from the circuit. We demonstrate theoretically how the effects of temperature and gas detection affect electron transport. To analyze thoroughly, the potential energy referred to as the Schotthy barrier perturbed by gasses is considered. Moreover, the energy transfer efficiency (ETE) of QD gas sensors for oxidizing or reducing gas is shown in the simulation. The results imply that the electron transport between QDs (raising the current and lessening the current) depends on a parameter corresponding with the Schotthy barrier. In regard to thermal energy portrayed by phonon baths, a higher temperature shortens the time duration of energy transport in QDs, hence raising energy transfer efficiency and energy current. Our model can be applied to further QD gas sensors’ design and manufacture.
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Affiliation(s)
| | - Jidapa Lakronwat
- Department of Physics, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Teerapat Uthailiang
- Department of Physics, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | | | - S. Boonchui
- Department of Physics, Faculty of Science, Kasetsart University, Bangkok, Thailand
- Center of Rubber and Polymer Materials in Agriculture and Industry (RPM), Faculty of Science, Kasetsart University, Bangkok, Thailand
- *Correspondence: S. Boonchui,
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13
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Li BW, Mei QX, Wu YK, Cai ML, Wang Y, Yao L, Zhou ZC, Duan LM. Observation of Non-Markovian Spin Dynamics in a Jaynes-Cummings-Hubbard Model Using a Trapped-Ion Quantum Simulator. PHYSICAL REVIEW LETTERS 2022; 129:140501. [PMID: 36240415 DOI: 10.1103/physrevlett.129.140501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 09/13/2022] [Indexed: 06/16/2023]
Abstract
The Jaynes-Cummings-Hubbard (JCH) model is a fundamental many-body model for light-matter interaction. As a leading platform for quantum simulation, the trapped ion system has realized the JCH model for two to three ions. Here, we report the quantum simulation of the JCH model using up to 32 ions. We verify the simulation results even for large ion numbers by engineering low excitations and thus low effective dimensions; then we extend to 32 excitations for an effective dimension of 2^{77}, which is difficult for classical computers. By regarding the phonon modes as baths, we explore Markovian or non-Markovian spin dynamics in different parameter regimes of the JCH model, similar to quantum emitters in a structured photonic environment. We further examine the dependence of the non-Markovian dynamics on the effective Hilbert space dimension. Our Letter demonstrates the trapped ion system as a powerful quantum simulator for many-body physics and open quantum systems.
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Affiliation(s)
- B-W Li
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
| | - Q-X Mei
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
| | - Y-K Wu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
| | - M-L Cai
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
- HYQ Co., Ltd., Beijing, 100176, People's Republic of China
| | - Y Wang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
| | - L Yao
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
- HYQ Co., Ltd., Beijing, 100176, People's Republic of China
| | - Z-C Zhou
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
| | - L-M Duan
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, People's Republic of China
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14
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Cavazzoni S, Razzoli L, Bordone P, Paris MGA. Perturbed graphs achieve unit transport efficiency without environmental noise. Phys Rev E 2022; 106:024118. [PMID: 36110011 DOI: 10.1103/physreve.106.024118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 08/01/2022] [Indexed: 06/15/2023]
Abstract
Coherent transport of an excitation through a network corresponds to continuous-time quantum walk on a graph, and the transport properties of the system may be radically different depending on the graph and on the initial state. The transport efficiency, i.e., the integrated probability of trapping at a certain vertex, is a measure of the success rate of the transfer process. Purely coherent quantum transport is known to be less efficient than the observed excitation transport, e.g., in biological systems, and there is evidence that environmental noise is indeed crucial for excitation transport. At variance with this picture, we here address purely coherent transport on highly symmetric graphs, and show analytically that it is possible to enhance the transport efficiency without environmental noise, i.e., using only a minimal perturbation of the graph. In particular, we show that adding an extra weight to one or two edges, depending on whether the initial state is localized or in a superposition of two vertex states, breaks the inherent symmetries of the graph and may be sufficient to achieve unit transport efficiency. We also briefly discuss the conditions to obtain a null transport efficiency, i.e., to avoid trapping.
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Affiliation(s)
- Simone Cavazzoni
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia, I-41125 Modena, Italy
| | - Luca Razzoli
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia, I-41125 Modena, Italy
- Dipartimento di Scienza e Alta Tecnologia, Università degli Studi dell'Insubria, I-22100 Como, Italy
| | - Paolo Bordone
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia, I-41125 Modena, Italy
- Centro S3, CNR-Istituto di Nanoscienze, I-41125 Modena, Italy
| | - Matteo G A Paris
- Quantum Technology Lab, Dipartimento di Fisica Aldo Pontremoli, Università degli Studi di Milano, I-20133 Milano, Italy
- INFN, Sezione di Milano, I-20133 Milano, Italy
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15
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Visuri AM, Giamarchi T, Kollath C. Symmetry-Protected Transport through a Lattice with a Local Particle Loss. PHYSICAL REVIEW LETTERS 2022; 129:056802. [PMID: 35960589 DOI: 10.1103/physrevlett.129.056802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
We study particle transport through a chain of coupled sites connected to free-fermion reservoirs at both ends, subjected to a local particle loss. The transport is characterized by calculating the conductance and particle density in the steady state using the Keldysh formalism for open quantum systems. In addition to a reduction of conductance, we find that transport can remain (almost) unaffected by the loss for certain values of the chemical potential in the lattice. We show that this "protected" transport results from the spatial symmetry of single-particle eigenstates. At a finite voltage, the density profile develops a drop at the lossy site, connected to the onset of nonballistic transport.
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Affiliation(s)
- A-M Visuri
- Physikalisches Institut, University of Bonn, Nussallee 12, 53115 Bonn, Germany
| | - T Giamarchi
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - C Kollath
- Physikalisches Institut, University of Bonn, Nussallee 12, 53115 Bonn, Germany
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16
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Kato S, Aoki T. Photon transport enhancement through a coupled-cavity QED system with dynamic modulation. OPTICS EXPRESS 2022; 30:6798-6807. [PMID: 35299458 DOI: 10.1364/oe.452080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/08/2022] [Indexed: 06/14/2023]
Abstract
We investigate photonic transport through fiber optical cavities under tunable fast modulation, which is induced by modulating atom-cavity coupling in a cavity quantum electrodynamics (CQED) system. The modulation bandwidth exceeds the timescales of all other system processes, such as cavity decay and atom-cavity coupling, and allows control of the dynamics of photonic transport through the cavity array. The transmission as a function of the modulation frequency clearly shows enhancement peaks in single cavity and two coupled-cavity cases. In particular, in the coupled-cavity case, the position of the enhancement peak is shifted due to the delocalized cavity field in the coupled system.
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17
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Bhatt RP, Kilinc J, Höcker L, Jendrzejewski F. Stochastic dynamics of a few sodium atoms in presence of a cold potassium cloud. Sci Rep 2022; 12:2422. [PMID: 35165302 PMCID: PMC8844084 DOI: 10.1038/s41598-022-05778-8] [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: 09/22/2021] [Accepted: 01/14/2022] [Indexed: 11/15/2022] Open
Abstract
Single particle resolution is a requirement for numerous experimental protocols that emulate the dynamics of small systems in a bath. Here, we accurately resolve through atom counting the stochastic dynamics of a few sodium atoms in presence of a cold potassium cloud. This capability enables us to rule out the effect of inter-species interaction on sodium atom number dynamics, at very low atomic densities present in these experiments. We study the noise sources for sodium and potassium in a common framework. Thereby, we assign the detection limits to 4.3 atoms for potassium and 0.2 atoms (corresponding to 96% fidelity) for sodium. This opens possibilities for future experiments with a few atoms immersed in a quantum degenerate gas.
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18
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Flannigan S, Damanet F, Daley AJ. Many-Body Quantum State Diffusion for Non-Markovian Dynamics in Strongly Interacting Systems. PHYSICAL REVIEW LETTERS 2022; 128:063601. [PMID: 35213192 DOI: 10.1103/physrevlett.128.063601] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/15/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
Capturing non-Markovian dynamics of open quantum systems is generally a challenging problem, especially for strongly interacting many-body systems. In this Letter, we combine recently developed non-Markovian quantum state diffusion techniques with tensor network methods to address this challenge. As a first example, we explore a Hubbard-Holstein model with dissipative phonon modes, where this new approach allows us to quantitatively assess how correlations spread in the presence of non-Markovian dissipation in a 1D many-body system. We find regimes where correlation growth can be enhanced by these effects, offering new routes for dissipatively enhancing transport and correlation spreading, relevant for both solid state and cold atom experiments.
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Affiliation(s)
- S Flannigan
- Department of Physics and SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
| | - F Damanet
- Institut de Physique Nucléaire, Atomique et de Spectroscopie, CESAM, University of Liège, B-4000 Liège, Belgium
| | - A J Daley
- Department of Physics and SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
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19
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Wang L, Wang Z, Wang C, Ren J. Cycle Flux Ranking of Network Analysis in Quantum Thermal Devices. PHYSICAL REVIEW LETTERS 2022; 128:067701. [PMID: 35213197 DOI: 10.1103/physrevlett.128.067701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 12/08/2021] [Accepted: 01/19/2022] [Indexed: 06/14/2023]
Abstract
Manipulating quantum thermal transport relies on uncovering the principle working cycles of quantum devices. Here we introduce the cycle flux ranking of network analysis to nonequilibrium thermal devices characterized as a quantum-transition network. To excavate the principal mechanism out of complex transport behaviors, we decompose the network into cycle trajectories, collect the cycle fluxes by algebraic graph theory, and select top-ranked cycle fluxes, i.e., the cycle trajectories with highest probabilities. We exemplify the cycle flux ranking in typical quantum device models, e.g., a thermal-drag spin-Seebeck pump and a quantum thermal transistor. Top-ranked cycle trajectories indeed elucidate the principal working mechanisms. Therefore, cycle flux ranking provides an alternative perspective that naturally describes the working cycle corresponding to the main functionality of quantum thermal devices, which would further guide the device optimization with desired performance.
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Affiliation(s)
- Luqin Wang
- Center for Phononics and Thermal Energy Science, China-EU Joint Lab on Nanophononics, Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Sciences and Engineering, Tongji University, Shanghai 200092, China
| | - Zi Wang
- Center for Phononics and Thermal Energy Science, China-EU Joint Lab on Nanophononics, Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Sciences and Engineering, Tongji University, Shanghai 200092, China
| | - Chen Wang
- Department of Physics, Zhejiang Normal University, Jinhua 321004, Zhejiang, People's Republic of China
| | - Jie Ren
- Center for Phononics and Thermal Energy Science, China-EU Joint Lab on Nanophononics, Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Sciences and Engineering, Tongji University, Shanghai 200092, China
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20
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Purkayastha A, Saha M, Agarwalla BK. Subdiffusive Phases in Open Clean Long-Range Systems. PHYSICAL REVIEW LETTERS 2021; 127:240601. [PMID: 34951774 DOI: 10.1103/physrevlett.127.240601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 09/26/2021] [Accepted: 11/03/2021] [Indexed: 06/14/2023]
Abstract
We show that a one-dimensional ordered fermionic lattice system with power-law-decaying hopping, when connected to two baths at its two ends with different chemical potentials at zero temperature, features two phases showing subdiffusive scaling of conductance with system size. These phases have no analogues in the isolated system (i.e., in absence of the baths) where the transport is perfectly ballistic. In the open system scenario, interestingly, there occurs two chemical-potential-driven subdiffusive to ballistic phase transitions at zero temperature. We discuss how these phase transitions, to our knowledge, are different from all the known nonequilibrium quantum phase transitions. We provide a clear understanding of the microscopic origin of these phases and argue that the subdiffusive phases are robust against the presence of arbitrary number-conserving many-body interactions in the system. These phases showing subdiffusive scaling of conductance with system size in a two-terminal setup are therefore universal properties of all ordered one-dimensional number-conserving fermionic systems with power-law-decaying hopping at zero temperature.
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Affiliation(s)
- Archak Purkayastha
- School of Physics, Trinity College Dublin, College Green, Dublin 2, Ireland
| | - Madhumita Saha
- Department of Physics, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Ward No. 8, NCL Colony, Pashan, Pune, Maharashtra 411008, India
- Department of Physics, Indian Institute of Technology Gandhinagar, Palaj, Gujarat 382355, India
| | - Bijay Kumar Agarwalla
- Department of Physics, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Ward No. 8, NCL Colony, Pashan, Pune, Maharashtra 411008, India
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21
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Hou B, Krems RV. Quantum transfer through small networks coupled to phonons: Effects of topology versus phonons. Phys Rev E 2021; 104:045302. [PMID: 34781495 DOI: 10.1103/physreve.104.045302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 09/14/2021] [Indexed: 11/07/2022]
Abstract
Particle or energy transfer through quantum networks is determined by network topology and couplings to environments. This study examines the combined effect of topology and external couplings on the efficiency of directional quantum transfer through quantum networks. We consider a microscopic model of qubit networks coupled to external vibrations by Holstein and Peierls couplings. By treating the positions of the network sites and the site-dependent phonon frequencies as independent variables, we determine the Hamiltonian parameters corresponding to minimum transfer time by Bayesian optimization. The results show that Holstein couplings may accelerate transfer through suboptimal network configurations but cannot accelerate quantum dynamics beyond the limit of the transfer time in an optimal phonon-free configuration. By contrast, Peierls couplings distort the optimal networks to accelerate quantum transfer through configurations with less than six sites. However, the speed-up offered by Peierls couplings decreases with the network size and disappears for networks with more than seven sites. For networks with seven sites or more, Peierls couplings distort the optimal network configurations and change the mechanism of quantum transfer but do not affect the lower limit of the transfer time. The machine-learning approach demonstrated here can be applied to determine quantum speed limits in other applications.
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Affiliation(s)
- B Hou
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
| | - R V Krems
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1.,Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
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22
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Suzuki F, Lemeshko M, Zurek WH, Krems RV. Anderson Localization of Composite Particles. PHYSICAL REVIEW LETTERS 2021; 127:160602. [PMID: 34723592 DOI: 10.1103/physrevlett.127.160602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 06/10/2021] [Accepted: 09/15/2021] [Indexed: 06/13/2023]
Abstract
We investigate the effect of coupling between translational and internal degrees of freedom of composite quantum particles on their localization in a random potential. We show that entanglement between the two degrees of freedom weakens localization due to the upper bound imposed on the inverse participation ratio by purity of a quantum state. We perform numerical calculations for a two-particle system bound by a harmonic force in a 1D disordered lattice and a rigid rotor in a 2D disordered lattice. We illustrate that the coupling has a dramatic effect on localization properties, even with a small number of internal states participating in quantum dynamics.
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Affiliation(s)
- Fumika Suzuki
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg, Austria
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
| | - Mikhail Lemeshko
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Wojciech H Zurek
- Theory Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Roman V Krems
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
- Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
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23
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Moreira SV, Marques B, Semião FL. Time-Dependent Dephasing and Quantum Transport. ENTROPY 2021; 23:e23091179. [PMID: 34573804 PMCID: PMC8469640 DOI: 10.3390/e23091179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/28/2021] [Accepted: 08/31/2021] [Indexed: 11/16/2022]
Abstract
The investigation of the phenomenon of dephasing assisted quantum transport, which happens when the presence of dephasing benefits the efficiency of this process, has been mainly focused on Markovian scenarios associated with constant and positive dephasing rates in their respective Lindblad master equations. What happens if we consider a more general framework, where time-dependent dephasing rates are allowed, thereby, permitting the possibility of non-Markovian scenarios? Does dephasing-assisted transport still manifest for non-Markovian dephasing? Here, we address these open questions in a setup of coupled two-level systems. Our results show that the manifestation of non-Markovian dephasing-assisted transport depends on the way in which the incoherent energy sources are locally coupled to the chain. This is illustrated with two different configurations, namely non-symmetric and symmetric. Specifically, we verify that non-Markovian dephasing-assisted transport manifested only in the non-symmetric configuration. This allows us to draw a parallel with the conditions in which time-independent Markovian dephasing-assisted transport manifests. Finally, we find similar results by considering a controllable and experimentally implementable system, which highlights the significance of our findings for quantum technologies.
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Affiliation(s)
- Saulo V. Moreira
- Department of Physics and NanoLund, Lund University, Box 118, 22100 Lund, Sweden
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC—UFABC, Santo André 09210-580, Brazil; (B.M.); (F.L.S.)
- Correspondence:
| | - Breno Marques
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC—UFABC, Santo André 09210-580, Brazil; (B.M.); (F.L.S.)
| | - Fernando L. Semião
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC—UFABC, Santo André 09210-580, Brazil; (B.M.); (F.L.S.)
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24
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Sellapillay K, Verga AD. Quantum walk on a graph of spins: Magnetism and entanglement. Phys Rev E 2021; 103:032123. [PMID: 33862687 DOI: 10.1103/physreve.103.032123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 02/23/2021] [Indexed: 11/07/2022]
Abstract
We introduce a model of a quantum walk on a graph in which a particle jumps between neighboring nodes and interacts with independent spins sitting on the edges. Entanglement propagates with the walker. We apply this model to the case of a one-dimensional lattice to investigate its magnetic and entanglement properties. In the continuum limit, we recover a Landau-Lifshitz equation that describes the precession of spins. A rich dynamics is observed, with regimes of particle propagation and localization, together with spin oscillations and relaxation. Entanglement of the asymptotic states follows a volume law for most parameters (the coin rotation angle and the particle-spin coupling).
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Affiliation(s)
- Kevissen Sellapillay
- Aix-Marseille Université, CPT, Campus de Luminy, case 907, 13288 Marseille, France
| | - Alberto D Verga
- Aix-Marseille Université, CPT, Campus de Luminy, case 907, 13288 Marseille, France
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25
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Tay BA. Excitation relaxation in a molecular chain and energy transfer at steady state. Phys Rev E 2021; 103:042124. [PMID: 34005972 DOI: 10.1103/physreve.103.042124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 03/23/2021] [Indexed: 11/07/2022]
Abstract
We consider the reduced dynamics of a molecular chain weakly coupled to a phonon bath. With a small and constant inhomogeneity in the coupling, the excitation relaxation rates are obtained in closed form. They are dominated by transitions between exciton modes lying next to each other in the energy spectrum. The rates are quadratic in the number of sites in a long chain. Consequently, the evolution of site occupation numbers exhibits longer coherence lifetime for short chains only. When external source and sink are added, the rate equations of exciton occupation numbers are similar to those obtained earlier by Fröhlich to explain energy storage and energy transfer in biological systems. There is a clear separation of timescale into a faster one pertaining to internal influence of the chain and phonon bath, and a slower one determined by external influence, such as the pumping rate of the source, the absorption rate of the sink, and the rate of radiation loss. The energy transfer efficiency at steady state depends strongly on these external parameters and is robust against a change in the internal parameters, such as temperature and inhomogeneity. Excitations are predicted to concentrate to the lowest energy mode when the source power is sufficiently high. In the site basis, this implies that when sustained by a high power source, a sink positioned at the center of the chain is more efficient in trapping energy than a sink placed at its end. Analytic expressions of energy transfer efficiency are obtained in the high power and low-power source limit. Parameters of a photosynthetic system are used as examples to illustrate the results.
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Affiliation(s)
- B A Tay
- Department of Foundation in Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
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26
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Davidson S, Fruchtman A, Pollock FA, Gauger EM. The dark side of energy transport along excitonic wires: On-site energy barriers facilitate efficient, vibrationally mediated transport through optically dark subspaces. J Chem Phys 2020; 153:134701. [PMID: 33032411 DOI: 10.1063/5.0023702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a novel, counter-intuitive method, based on dark-state protection, for significantly improving exciton transport efficiency through "wires" comprising a chain of molecular sites with an intrinsic energy gradient. Specifically, by introducing "barriers" to the energy landscape at regular intervals along the transport path, we find that undesirable radiative recombination processes are suppressed due to a clear separation of sub-radiant and super-radiant eigenstates in the system. This, in turn, can lead to an improvement in transmitted power by many orders of magnitude, even for very long chains. From there, we analyze the robustness of this phenomenon to changes in both system and environment properties to show that this effect can be beneficial over a range of different thermal and optical environment regimes. Finally, we show that the novel energy landscape presented here may provide a useful foundation for overcoming the short length scales over which exciton diffusion typically occurs in organic photo-voltaics and other nanoscale transport scenarios, thus leading to considerable potential improvements in the efficiency of such devices.
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Affiliation(s)
- Scott Davidson
- SUPA, Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Amir Fruchtman
- Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom
| | - Felix A Pollock
- School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia
| | - Erik M Gauger
- SUPA, Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
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27
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Ren W, Liu W, Song C, Li H, Guo Q, Wang Z, Zheng D, Agarwal GS, Scully MO, Zhu SY, Wang H, Wang DW. Simultaneous Excitation of Two Noninteracting Atoms with Time-Frequency Correlated Photon Pairs in a Superconducting Circuit. PHYSICAL REVIEW LETTERS 2020; 125:133601. [PMID: 33034504 DOI: 10.1103/physrevlett.125.133601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 08/28/2020] [Indexed: 06/11/2023]
Abstract
We report the first observation of simultaneous excitation of two noninteracting atoms by a pair of time-frequency correlated photons in a superconducting circuit. The strong coupling regime of this process enables the synthesis of a three-body interaction Hamiltonian, which allows the generation of the tripartite Greenberger-Horne-Zeilinger state in a single step with a fidelity as high as 0.95. We further demonstrate the inhibition of the simultaneous two-atom excitation by continuously measuring whether the first photon is emitted. This work provides a new route in synthesizing many-body interaction Hamiltonian and coherent control of entanglement.
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Affiliation(s)
- Wenhui Ren
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Wuxin Liu
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Chao Song
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Hekang Li
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
- Institute of Physics, Chinese Academy of Sciences, Bejing 100190, China
| | - Qiujiang Guo
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Zhen Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Dongning Zheng
- Institute of Physics, Chinese Academy of Sciences, Bejing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Bejing 100190, China
| | - Girish S Agarwal
- Institute for Quantum Science and Engineering, Departments of Biological and Agricultural Engineering, Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
| | - Marlan O Scully
- Institute for Quantum Science and Engineering, Departments of Biological and Agricultural Engineering, Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
- Baylor University, Waco, Texas 76706, USA
| | - Shi-Yao Zhu
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - H Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Da-Wei Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Bejing 100190, China
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28
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Finsterhölzl R, Katzer M, Knorr A, Carmele A. Using Matrix-Product States for Open Quantum Many-Body Systems: Efficient Algorithms for Markovian and Non-Markovian Time-Evolution. ENTROPY (BASEL, SWITZERLAND) 2020; 22:E984. [PMID: 33286753 PMCID: PMC7597300 DOI: 10.3390/e22090984] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/28/2020] [Accepted: 09/01/2020] [Indexed: 11/20/2022]
Abstract
This paper presents an efficient algorithm for the time evolution of open quantum many-body systems using matrix-product states (MPS) proposing a convenient structure of the MPS-architecture, which exploits the initial state of system and reservoir. By doing so, numerically expensive re-ordering protocols are circumvented. It is applicable to systems with a Markovian type of interaction, where only the present state of the reservoir needs to be taken into account. Its adaption to a non-Markovian type of interaction between the many-body system and the reservoir is demonstrated, where the information backflow from the reservoir needs to be included in the computation. Also, the derivation of the basis in the quantum stochastic Schrödinger picture is shown. As a paradigmatic model, the Heisenberg spin chain with nearest-neighbor interaction is used. It is demonstrated that the algorithm allows for the access of large systems sizes. As an example for a non-Markovian type of interaction, the generation of highly unusual steady states in the many-body system with coherent feedback control is demonstrated for a chain length of N=30.
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Affiliation(s)
- Regina Finsterhölzl
- Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Hardenbergstraße 36, 10623 Berlin, Germany; (M.K.); (A.K.); (A.C.)
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29
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Ghasemi F, Shafiee A. An investigation into the energy transfer efficiency of a two-pigment photosynthetic system using a macroscopic quantum model. Biosystems 2020; 197:104209. [PMID: 32730839 DOI: 10.1016/j.biosystems.2020.104209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 07/03/2020] [Accepted: 07/05/2020] [Indexed: 11/17/2022]
Abstract
Despite several different measures of efficiency that are applicable to the photosynthetic systems, a precise degree of efficiency of these systems is not completely determined. Introducing an efficient model for the dynamics of light-harvesting complexes in biological environments is a major purpose in investigating such systems. Here, we investigate the effect of macroscopic quantum behavior of a system of two pigments on the transport phenomena in this system model which interacts with an oscillating environment. We use the second-order perturbation theory to calculate the time-dependent population of excitonic states of a two-dimensional Hamiltonian using a non-master equation approach. Our results demonstrate that the quantum efficiency is robust with respect to the macroscopicity parameter h˜ solely, but the ratio of macroscopicity over the pigment-pigment interaction energy can be considered as a parameter that may control the energy transfer efficiency at a given time. So, the dynamical behavior and the quantum efficiency of the supposed photosynthetic system may be influenced by a change in the macroscopic behavior of the system.
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Affiliation(s)
- Fatemeh Ghasemi
- Research Group on Foundations of Quantum Theory and Information, Department of Chemistry, Sharif University of Technology, P.O.Box 11365-9516, Tehran, Iran.
| | - Afshin Shafiee
- Research Group on Foundations of Quantum Theory and Information, Department of Chemistry, Sharif University of Technology, P.O.Box 11365-9516, Tehran, Iran.
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30
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Kim CW, Rhee YM. Toward monitoring the dissipative vibrational energy flows in open quantum systems by mixed quantum-classical simulations. J Chem Phys 2020; 152:244109. [PMID: 32610983 DOI: 10.1063/5.0009867] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
In open quantum system dynamics, rich information about the major energy relaxation channels and corresponding relaxation rates can be elucidated by monitoring the vibrational energy flow among individual bath modes. However, such calculations often become tremendously difficult as the complexity of the subsystem-bath coupling increases. In this paper, we attempt to make this task feasible by using a mixed quantum-classical method, the Poisson-bracket mapping equation with non-Hamiltonian modification (PBME-nH) [H. W. Kim and Y. M. Rhee, J. Chem. Phys. 140, 184106 (2014)]. For a quantum subsystem bilinearly coupled to harmonic bath modes, we derive an expression for the mode energy in terms of the classical positions and momenta of the nuclei, while keeping consistency with the energy of the quantum subsystem. The accuracy of the resulting expression is then benchmarked against a numerically exact method by using relatively simple models. Although our expression predicts a qualitatively correct dissipation rate for a range of situations, cases involving a strong vibronic resonance are quite challenging. This is attributed to the inherent lack of quantum back reaction in PBME-nH, which becomes significant when the subsystem strongly interacts with a small number of bath modes. A rigorous treatment of such an effect will be crucial for developing quantitative simulation methods that can handle generic subsystem-bath coupling.
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Affiliation(s)
- Chang Woo Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Young Min Rhee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
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31
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Hauke P, Katzgraber HG, Lechner W, Nishimori H, Oliver WD. Perspectives of quantum annealing: methods and implementations. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2020; 83:054401. [PMID: 32235066 DOI: 10.1088/1361-6633/ab85b8] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Quantum annealing is a computing paradigm that has the ambitious goal of efficiently solving large-scale combinatorial optimization problems of practical importance. However, many challenges have yet to be overcome before this goal can be reached. This perspectives article first gives a brief introduction to the concept of quantum annealing, and then highlights new pathways that may clear the way towards feasible and large scale quantum annealing. Moreover, since this field of research is to a strong degree driven by a synergy between experiment and theory, we discuss both in this work. An important focus in this article is on future perspectives, which complements other review articles, and which we hope will motivate further research.
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Affiliation(s)
- Philipp Hauke
- INO-CNR BEC Center and Department of Physics, University of Trento, 38123Povo (TN), Italy. Kirchhoff-Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany. Institute for Theoretical Physics, Heidelberg University, 69120 Heidelberg, Germany
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32
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Takahashi S, Watanabe K. Decoupling from a Thermal Bath via Molecular Polariton Formation. J Phys Chem Lett 2020; 11:1349-1356. [PMID: 32017569 DOI: 10.1021/acs.jpclett.9b03789] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The coupling between an electronic system and an environmental bath plays a decisive role in the excited state dynamics of artificial/natural molecular condensed phases. Although it is generally difficult to control the coupling between the system and the thermal bath in condensed matter, a strong light-matter coupling can control system-bath coupling properties using the polaron decoupling effect, in which a coherent interaction between excitons and photons reduces the reorganization energy. Here we demonstrate that this polaron decoupling strongly reduces the fluctuations in electronic energy in tetraphenyldibenzoperiflanthene thin films embedded in an optical microcavity. Using two-dimensional electronic spectroscopy, the frequency-fluctuation correlation function of the lower polariton state was revealed, showing that the dynamic inhomogeneity due to bath coupling inside the microcavity almost vanishes completely. This was attributed to a significant delocalization of the lower polariton state over 105 molecules in the cavity, reducing the effective coupling strength of the bath modes.
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Affiliation(s)
- Shota Takahashi
- Department of Chemistry, Graduate School of Science , Kyoto University , Kyoto , 606-8502 , Japan
| | - Kazuya Watanabe
- Department of Chemistry, Graduate School of Science , Kyoto University , Kyoto , 606-8502 , Japan
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33
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Dephasing-Assisted Macrospin Transport. ENTROPY 2020; 22:e22020210. [PMID: 33285985 PMCID: PMC7516640 DOI: 10.3390/e22020210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/07/2020] [Accepted: 02/10/2020] [Indexed: 11/29/2022]
Abstract
Transport phenomena are ubiquitous in physics, and it is generally understood that the environmental disorder and noise deteriorates the transfer of excitations. There are, however, cases in which transport can be enhanced by fluctuations. In the present work, we show, by means of micromagnetics simulations, that transport efficiency in a chain of classical macrospins can be greatly increased by an optimal level of dephasing noise. We also demonstrate the same effect in a simplified model, the dissipative Discrete Nonlinear Schrödinger equation, subject to phase noise. Our results point towards the realization of a large class of magnonics and spintronics devices, where disorder and noise can be used to enhance spin-dependent transport efficiency.
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34
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Saha M, Purkayastha A, Maiti SK. More current with less particles due to power-law hopping. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:025303. [PMID: 31519006 DOI: 10.1088/1361-648x/ab4494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We reveal interesting universal transport behavior of ordered one-dimensional fermionic systems with power-law hopping. We restrict ourselves to the case where the power-law decay exponent [Formula: see text], so that the thermodynamic limit is well-defined. We explore the quantum phase-diagram of the non-interacting model in terms of the zero temperature Drude weight, which can be analytically calculated. Most interestingly, we reveal that for [Formula: see text], there is a phase where the zero temperature Drude weight diverges as filling fraction goes to zero. Thus, in this regime, counter intuitively, reducing number of particles increases transport and is maximum for a sub-extensive number of particles. Being a statement about zero-filling, this transport behavior is immune to adding number conserving interaction terms. We have explicitly checked this using two different interacting systems. We propose that measurement of persistent current due to a flux through a mesoscopic ring with power-law hopping will give an experimental signature of this phase. In persistent current, the signature of this phase survives up to a finite temperature for a finite system. At higher temperatures, a crossover is seen. The maximum persistent current shows a power-law decay at high temperatures. This is in contrast with short ranged systems, where the persistent current decays exponentially with temperature.
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Affiliation(s)
- Madhumita Saha
- Physics and Applied Mathematics Unit, Indian Statistical Institute, 203 Barrackpore Trunk Road, Kolkata-700 108, India
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35
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Mendoza-Arenas JJ, Gómez-Ruiz FJ, Rodríguez FJ, Quiroga L. Enhancing violations of Leggett-Garg inequalities in nonequilibrium correlated many-body systems by interactions and decoherence. Sci Rep 2019; 9:17772. [PMID: 31780693 PMCID: PMC6882789 DOI: 10.1038/s41598-019-54121-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 10/22/2019] [Indexed: 11/09/2022] Open
Abstract
We identify different schemes to enhance the violation of Leggett-Garg inequalities in open many-body systems. Considering a nonequilibrium archetypical setup of quantum transport, we show that particle interactions control the direction and amplitude of maximal violation, and that in the strongly-interacting and strongly-driven regime bulk dephasing enhances the violation. Through an analytical study of a minimal model we unravel the basic ingredients to explain this decoherence-enhanced quantumness, illustrating that such an effect emerges in a wide variety of systems.
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Affiliation(s)
- J J Mendoza-Arenas
- Departamento de Física, Universidad de los Andes, A.A. 4976, Bogotá, D. C., Colombia
| | - F J Gómez-Ruiz
- Departamento de Física, Universidad de los Andes, A.A. 4976, Bogotá, D. C., Colombia. .,Donostia International Physics Center, E-20018, San Sebastián, Spain.
| | - F J Rodríguez
- Departamento de Física, Universidad de los Andes, A.A. 4976, Bogotá, D. C., Colombia
| | - L Quiroga
- Departamento de Física, Universidad de los Andes, A.A. 4976, Bogotá, D. C., Colombia
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36
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Obšil P, Lešundák A, Pham T, Lakhmanskiy K, Podhora L, Oral M, Číp O, Slodička L. A room-temperature ion trapping apparatus with hydrogen partial pressure below 10 -11 mbar. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:083201. [PMID: 31472618 DOI: 10.1063/1.5104346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 08/04/2019] [Indexed: 06/10/2023]
Abstract
The lifetime of trapped ion ensembles corresponds to a crucial parameter determining the potential scalability of their prospective applications and is often limited by the achievable vacuum level in the apparatus. We report on the realization of a room-temperature 40Ca+ ion trapping vacuum apparatus with unprecedentedly low reaction rates of ions with a dominant vacuum contaminant: hydrogen. We present our trap assembly procedures and hydrogen pressure characterization by analysis of the CaH+ molecule formation rate.
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Affiliation(s)
- P Obšil
- Department of Optics, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czech Republic
| | - A Lešundák
- Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 612 64 Brno, Czech Republic
| | - T Pham
- Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 612 64 Brno, Czech Republic
| | - K Lakhmanskiy
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - L Podhora
- Department of Optics, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czech Republic
| | - M Oral
- Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 612 64 Brno, Czech Republic
| | - O Číp
- Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 612 64 Brno, Czech Republic
| | - L Slodička
- Department of Optics, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czech Republic
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37
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Wang L, Allodi MA, Engel GS. Quantum coherences reveal excited-state dynamics in biophysical systems. Nat Rev Chem 2019. [DOI: 10.1038/s41570-019-0109-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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38
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Abstract
We present a field-theory description of ultracold bosonic atoms in the presence of a disordered external potential. By means of functional integration techniques, we aim to investigate and review the interplay between disordered energy landscapes and fluctuations, both thermal and quantum ones. Within the broken-symmetry phase, up to the Gaussian level of approximation, the disorder contribution crucially modifies both the condensate depletion and the superfluid response. Remarkably, it is found that the ordered (i.e., superfluid) phase can be destroyed also in regimes where the random external potential is suitable for a perturbative analysis. We analyze the simplest case of quenched disorder and then we move to present the implementation of the replica trick for ultracold bosonic systems. In both cases, we discuss strengths and limitations of the reviewed approach, paying specific attention to possible extensions and the most recent experimental outputs.
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