Review
Physics, Multidisciplinary
Si-Yuan Bai, Chong Chen, Hong Wu, Jun-Hong An
Summary: Quantum technology utilizes quantum resources for innovation and controlling decoherence is crucial for protecting these resources. Studies have shown that the system-environment energy spectrum plays a role in determining decoherence, and the formation of bound states can help suppress it.
ADVANCES IN PHYSICS-X
(2021)
Article
Physics, Condensed Matter
Huan-Yu Wang, Xiao-Ming Zhao, Lin Zhuang, Wu-Ming Liu
Summary: This study proposes a non-Floquet theory to characterize the topological phases of time-periodic open quantum systems and demonstrates its application through the analysis of a non-Hermitian bipartite chain. The research also shows the potential of utilizing different starting points of the driving period to design quantum detectors of phases in dissipative oscillating fields. The methods introduced in this study can describe topological features in various types of dynamical open quantum systems and contribute to the development of new types of dynamical topological materials.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Multidisciplinary Sciences
Kazutaka Takahashi
Summary: This article discusses the dynamics of periodically driven open quantum systems, focusing on the time evolution of the quantum state and the influence of the dissipator on the system behavior. It is found that the correlation between the population part and the coherence part of the density operator is induced by an adiabatic gauge potential. The introduction of the counterdiabatic term eliminates this correlation, but additional correlations prevent convergence to the equilibrium state. The performance of the control by the counterdiabatic term is studied, and it is found to strongly depend on the relations between the system's different scales.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2022)
Article
Chemistry, Physical
Mohit Bansal, Ramesh Ramachandran
Summary: This report focuses on the formal description of the excitation of double-quantum transitions in three-level systems in magnetic resonance. By employing the Floquet theory and density operator formalism, the excitation process during a pulse at non-stroboscopic time intervals is analyzed using generalized time-propagators. Unlike numerical simulations, the analytical expressions provide insights into the excitation phenomenon and facilitate faster experimental optimization and data quantification.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Physics, Multidisciplinary
Mahmoud M. Asmar, Wang-Kong Tse
Summary: A new theory regarding the RKKY interaction mediated by a two-dimensional electron system under periodic driving is presented, with calculations conducted in a 2D metal with parallel ferromagnetic chains. The study reveals new non-analytic features in the time-averaged spin susceptibility. Depending on the strength of the light-matter coupling, the RKKY interaction can exhibit oscillatory behavior or remain purely ferromagnetic, offering potential for dynamic control of the indirect exchange interaction in 2D magnetic structures.
NEW JOURNAL OF PHYSICS
(2021)
Review
Physics, Condensed Matter
Arnab Sen, Diptiman Sen, K. Sengupta
Summary: This paper provides a brief overview of analytic perturbative techniques for computing the Floquet Hamiltonian of periodically driven quantum many-body systems. The key technical points of each method are presented in a pedagogical manner, along with discussions on their applications and insights provided. Additionally, some open problems that could potentially be addressed using these methods are also discussed.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Materials Science, Multidisciplinary
Weiwei Zhu, Y. D. Chong, Jiangbin Gong
Summary: Floquet higher-order topological insulators (FHOTIs) are a novel topological phase that can occur in periodically driven lattices. An experimentally realistic bipartite system can host FHOTI phases and exhibit interesting phase transitions without breaking lattice symmetry. In the FHOTI phase, the lattice features corner modes at specific eigenphases that are robust against disorder.
Article
Materials Science, Multidisciplinary
Aritra Kundu, Atanu Rajak, Tanay Nag
Summary: Studying the classical kicked rotor system has revealed a prethermal phase before entering the chaotic heating regime, characterized by diffusive transport of fluctuation and a hydrodynamic picture in a generalized Gibbs ensemble. The heating regime is marked by diffusive growth of kinetic energy with sharp localization of correlation, connecting the prethermal phase to the heating phase. Relative phase matching concept is used to explain the numerically observed phenomena and exploit statistical uncorrelated nature of angles to find analytical form of correlator in the heating regime.
Article
Physics, Multidisciplinary
Yuta Murotani, Natsuki Kanda, Tatsuhiko N. Ikeda, Takuya Matsuda, Manik Goyal, Jun Yoshinobu, Yohei Kobayashi, Susanne Stemmer, Ryusuke Matsunaga
Summary: Using broadband multi-terahertz spectroscopy, researchers found that stimulated Rayleigh scattering dominates the transient optical conductivity of cadmium arsenide under an optical driving field at 30 THz. The characteristic dispersive line shape with net optical gain is attributed to optical transitions between light-induced Floquet subbands, greatly enhanced by the longitudinal plasma mode. This unprecedented stimulated Rayleigh scattering with a large refractive index change could enable slow light generation in conductive solids at room temperature.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Abhiram Soori
Summary: We propose a superconductor-normal metal-superconductor (SNS) junction where Josephson diode effect manifests when the normal metal region is driven. Time reversal symmetry and inversion symmetry need to be broken in the SNS junction for the diode effect to show up. We calculate long time averaged current and show that the system exhibits diode effect for two configurations of the driven SNS junction.
Article
Engineering, Mechanical
Alvaro A. Grandi, Suzie Protiere, Arnaud Lazarus
Summary: Dynamical stabilization is the ability to stabilize a diverging stationary state by periodically modulating its physical properties in time. This phenomenon is currently of interest in the study of Floquet engineering as it leads to the development of new exotic states of matter in the quantum realm. Nowadays, dynamical stabilization is achieved by applying periodic modulations that are much faster than the natural diverging time of the system, allowing for effective stationary equations to be used. This work combines theoretical models and precision desktop experiments to demonstrate the possibility of dynamically stabilizing a system by periodically injecting the right amount of external action in a pulse wave manner. An analogy between this stability problem and the determination of bound states and energy levels in quantum mechanics provides a universal semi-analytical design tool for dynamically stabilizing a mass in a square-wave varying potential energy.
NONLINEAR DYNAMICS
(2023)
Article
Physics, Multidisciplinary
David Viennot
Summary: The effective Hamiltonian theory presented in this study is suitable for quasi-periodically and chaotically driven quantum systems. It is based on the Koopman approach, which generalizes the Floquet approach used for periodically driven systems. The quasi-energy states are shown to act as quasi-recurrent states in the quantum system.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2021)
Article
Physics, Multidisciplinary
Phatthamon Kongkhambut, Hans Kessler, Jim Skulte, Ludwig Mathey, Jayson G. Cosme, Andreas Hemmerich
Summary: By resonantly shaking the pump field in an atom-cavity system, a periodically driven open three-level Dicke model was realized, showing the emergence of a dynamical phase where atoms periodically localize between the antinodes of the pump lattice. This dynamical phase was observed through the periodic switching of relative phase between the pump and cavity fields at a small fraction of the driving frequency, suggesting a time crystalline character.
PHYSICAL REVIEW LETTERS
(2021)
Article
Optics
Ronja Hotz, Gernot Schaller
Summary: For selected periodically driven open quantum systems, dynamically adapted coarse-graining time yields the best results among different coarse-graining schemes, at a high computational cost. This non-Markovian dynamics interpolates through a series of individually Markovian solutions.
Article
Physics, Fluids & Plasmas
Maicol A. Ochoa
Summary: We investigate the energy distribution and quantum thermodynamics in periodically-driven polaritonic systems at room temperature. We study the energy reorganization between two systems and their interaction as a function of coupling strength, driving force, and detuning. By deriving the quantum master equation and calculating the long-time evolution, we obtain the equilibrium state of the system.
Article
Nanoscience & Nanotechnology
Masamichi Nishino, Ismail Enes Uysal, Taichi Hinokihara, Seiji Miyashita
Summary: The study focuses on investigating the static and dynamic properties of the Nd permanent magnet, Nd2Fe14B, and presents the temperature dependence of magnetizations, domain wall profiles, and ferromagnetic resonance frequency. Additionally, the coercive force of a single grain is estimated using a statistical method, showing the surface anisotropy effect of Nd atoms on coercive force and magnetic fields in a hard-soft-hard magnet model.
Article
Physics, Multidisciplinary
Tatsuhiko Shirai, Shu Tanaka
Summary: This study investigates the dynamical critical exponent of disordered Ising chains under transverse fields to examine the effect of a correlated disorder on quantum phase transitions. The results show that the dynamical critical exponent in the presence of correlated disorder is finite, while it is infinite in cases of uncorrelated disorder. Additionally, the dynamical critical exponent is found to depend on the tuning process of the transverse field strengths.
Review
Materials Science, Multidisciplinary
Seiji Miyashita, Masamichi Nishino, Yuta Toga, Taichi Hinokihara, Ismail Enes Uysal, Takashi Miyake, Hisazumi Akai, Satoshi Hirosawa, Akimasa Sakuma
Summary: This article focuses on the thermal properties of Nd2Fe14B magnet and methods of studying them, covering various thermodynamic properties and coercivity, as well as the effects of dipole-dipole interaction in large grains. The study also includes the analysis of surface nucleation and the distribution of properties of grains from the viewpoint of first-order reversal curve.
SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS
(2021)
Article
Physics, Applied
Masamichi Nishino, Yogendra Singh, Kamel Boukheddaden, Seiji Miyashita
Summary: The paper introduces elastic interaction models for spin-crossover (SC) compounds and multistep transitions, analyzing phase diagrams including metastable phases for several SC systems. It also investigates SC transitions in core-shell SC nanocomposites composed of two different compounds.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Condensed Matter
Hans De Raedt, Seiji Miyashita, Kristel Michielsen, Herve Vezin, Sylvain Bertaina, Irinel Chiorescu
Summary: Recent electron spin resonance experiments have shown that sustained Rabi oscillations can be achieved by driving a magnetic moment with microwave fields. This paper investigates the interactions between microwave drives and three relaxation mechanisms using numerical and analytical techniques. In addition, two microscopic models are proposed to describe the effects of microwave fields and interactions on Rabi oscillations.
EUROPEAN PHYSICAL JOURNAL B
(2022)
Article
Computer Science, Hardware & Architecture
Tatsuhiko Shirai, Nozomu Togawa
Summary: We propose a spin-variable reduction method for Ising machines to handle linear equality constraints in combinatorial optimization problems. The method reduces the number of binary variables compared to the conventional penalty method and demonstrates its applicability to various combinatorial optimization problems. Experiments show that the spin-variable reduction method outperforms the penalty method in Ising machines, extending their application to larger combinatorial optimization problems with linear equality constraints.
IEEE TRANSACTIONS ON COMPUTERS
(2023)
Editorial Material
Physics, Applied
Kamel Boukheddaden, Seiji Miyashita, Smail Triki
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Multidisciplinary
Takashi Mori, Tatsuhiko Shirai
Summary: Markovian open quantum systems exhibit complex relaxation dynamics. The spectral gap of the Liouvillian characterizes the decay rate towards the steady state, but it may not accurately estimate the relaxation time due to a long crossover time. We introduce the symmetrized Liouvillian gap to provide a rigorous upper bound on the transient decay of autocorrelation functions in the steady state. Numerical results show that the symmetrized Liouvillian gap always gives a correct upper bound, while the standard Liouvillian gap does not.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Applied
Giovanni Franco-Rivera, Josiah Cochran, Seiji Miyashita, Sylvain Bertaina, Irinel Chiorescu
Summary: We demonstrate a strong coupling between a Gd3+ spin ensemble in a scheelite single crystal and a superconducting cavity, resulting in a large separation of spin-photon states. The interaction is well described by the Dicke model and crystal-field Hamiltonian. The presence of photons in the cavity induces changes in the crystal-field parameters and perturbs the crystal ground state. Numerical calculations estimate the cavity sensing volume and the average spin-photon coupling strength to be approximately 620 Hz.
PHYSICAL REVIEW APPLIED
(2023)
Article
Materials Science, Multidisciplinary
Masamichi Nishino, Hiroshi Hayasaka, Seiji Miyashita
Summary: This study investigates the enhancement mechanism of the radial shell in dysprosium magnets, and identifies the features and mechanisms of coercivity enhancement using an atomistic model. The results show that a change from surface to bulk nucleation significantly enhances coercivity, especially at high temperatures.
Article
Materials Science, Multidisciplinary
Hiroshi Hayasaka, Masamichi Nishino, Seiji Miyashita
Summary: The angular dependence of coercivity in permanent magnets is explored in this study. The investigation includes the effects of temperature and thermal fluctuations on magnetization reversal. The study reveals differences in magnetization reversal mechanisms at zero and finite temperatures, as well as variations in the angular dependences of nucleation and pinning fields. The thermal fluctuation reduces threshold fields, alters angular dependences, and narrows the gap between nucleation and pinning fields. Additionally, the alignment distribution of grains impacts the angular dependences of threshold fields.
Article
Computer Science, Information Systems
Kensuke Tamura, Tatsuhiko Shirai, Hosho Katsura, Shu Tanaka, Nozomu Togawa
Summary: The performance differences among binary-integer encodings in an Ising machine are investigated, with unary encoding showing the best performance for large-sized problems under inequality constraints.
Article
Physics, Fluids & Plasmas
Hayate Nakano, Tatsuhiko Shirai, Takashi Mori
Summary: This study investigates the relaxation dynamics of nonintegrable quantum many-body systems in the thermodynamic limit using a tensor-network formalism. By simulating the Lindblad quantum master equation (LQME) and measuring thermodynamic equivalence between states described by uniform matrix product operators (MPO), it is shown numerically that the time evolved state of an initial thermal Gibbs state in LQME is indistinguishable from a Gibbs state with a time-dependent effective temperature in the weak-dissipation and thermodynamic limit.
Article
Materials Science, Multidisciplinary
Taichi Hinokihara, Seiji Miyashita
Summary: This study investigates various magnetic configurations caused by dipole-dipole interaction in thin-film magnets with perpendicular anisotropy under open boundary conditions. The research identifies five typical configurations and observes a unique magnetic-domain pattern resulting from the open boundary conditions.
Article
Materials Science, Multidisciplinary
Hiroaki Onishi, Seiji Miyashita
Summary: Finite-temperature properties of a Hubbard model including particle bath sites were studied using numerical methods. The specific heat showed peaks corresponding to different energy scales of ordering processes, with magnetic correlations developing at very low temperatures. Depending on parameters, the system exhibited either an itinerant ferromagnetic or antiferromagnetic state, with competition between magnetic states leading to a peculiar ordering process of local spin correlations.
