Article
Physics, Multidisciplinary
Jeong Ryeol Choi
Summary: The researcher has developed a quantum formalism based on a linear invariant theorem to provide an exact quantum-classical correspondence for damped oscillatory systems perturbed by arbitrary forces, removing the global quantum constant from their quantum results. The study specifically illustrates the precise correspondence of quantum energy with classical energy.
FRONTIERS IN PHYSICS
(2021)
Article
Optics
K. Raimundo, M. C. Baldiotti, R. Fresneda, C. Molina
Summary: In this work, a classical-quantum correspondence for two-level pseudo-Hermitian systems is proposed and analyzed. The presence of a complex external field is described by a pseudo-Hermitian Hamiltonian through a suitable canonical transformation. A covariant quantization scheme is constructed to map canonically related pseudoclassical theories to unitarily equivalent quantum realizations, maintaining a unique metric-inducing isometry between distinct Hilbert spaces.
Article
Chemistry, Physical
Marco Schiro, Florian G. Eich, Federica Agostini
Summary: The trajectory-based approach developed for excited-state molecular dynamics simulations of systems subject to an external periodic drive combines exact-factorization formalism with the Floquet formalism. This approach approximates quantum dynamics by combining classical-like, trajectory-based, nuclear evolution with electronic dynamics represented in the Floquet basis. The resulting algorithm, an extension of the coupled-trajectory mixed quantum-classical scheme, has been successfully applied to a model study with different field intensities.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Physics, Multidisciplinary
Angel S. Sanz
Summary: The article investigates the classical analogs of quantum states in phase space by studying the behavior of classical analogs arising from interfering Wigner distribution functions. The dynamical evolution of entropy is computed for a bipartite system under regular and chaos conditions, and the results are compared with classical counterparts. It is found that entropy provides information about system delocalization rather than entanglement production.
Article
Physics, Multidisciplinary
Nimrod Moiseyev, Milan Sindelka
Summary: This article investigates the influence of the coupling strength between an atom or a molecule and the modes of a cavity on the correspondence between quantum mechanics and classical mechanics. It is found that the coupling strength can be tuned to adjust the relationship between the two. Additionally, effective cavity-matter dynamics, which are approximately decoupled, can be obtained under both weak and strong coupling regimes.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2022)
Article
Physics, Multidisciplinary
Serena Fazzini, Piotr Chudzinski, Christoph Dauer, Imke Schneider, Sebastian Eggert
Summary: Studying time-periodic fields in a one-dimensional quantum gas allows for the exploration of novel quantum states and quantum engineering, particularly the intriguing interaction between Floquet states and strong interactions. By developing a time-periodic operator algebra, the complex valued Floquet eigenenergies and resonant states can be analyzed, leading to predictions of changes in experimental systems of Lieb-Liniger bosons.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
A. A. Shevyrin, S. Rathi, P. See, I. Farrer, D. Ritchie, J. Griffiths, G. Jones, S. Kumar
Summary: In this study, magnetocapacitance and magnetoresistance measurements were used to investigate nonequilibrium phenomena in a bilayer electron system based on GaAs/AlGaAs heterostructures. The magnetic field ramping causes the bilayer electron system to be out of equilibrium, resulting in magnetoresistance hysteresis and spikes. Interestingly, magnetocapacitance results show hysteresis even when both layers are in the quantum Hall state. The hysteresis is accompanied by interlayer charge transfer, but the disequilibrium is not limited to interlayer imbalance. Results show that the edge-bulk imbalance can be the initial ground for the appearance of hysteresis. In addition, non-equilibrium states are observed in which the total layer densities determine the magnetic field and gate voltage dependencies, instead of individual layer densities.
Article
Physics, Multidisciplinary
Ahana Chakraborty, Rajdeep Sensarma
Summary: This study introduces a new field theoretic method for calculating Renyi entropy of interacting bosons in subsystems without using replica methods. The method can be applied to dynamics of open and closed quantum systems, and can determine the relationship between the initial state and final density matrix to predict the behavior of entropy over time. The approach also shows that the entropy in non-Markovian dynamics approaches a steady-state value with exponents determined by nonanalyticities of the system's environment.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Kazuyuki Kuroyama, Sadashige Matsuo, Jo Muramoto, Shunsuke Yabunaka, Sascha R. Valentin, Arne Ludwig, Andreas D. Wieck, Yasuhiro Tokura, Seigo Tarucha
Summary: We report experimental observations of charge-spin cooperative dynamics of two-electron states in a GaAs double quantum dot located in a nonequilibrium phonon environment. The spin-flip rate of a single electron is significantly enhanced when the phonon energy exceeds the lowest excitation energy in the quantum dot. In addition, the spatial gradient of phonon density between the dots leads to a higher probability of parallel spin states than antiparallel ones.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Wang Zi, Ren Jie
Summary: By analyzing the geometric phase and thermodynamic length in the transport process and the energy conversion process of driven nonequilibrium quantum systems, this review provides a unified perspective for recent research. The discussion over thermodynamic geometry yields multiple constraints on transport and energy conversion, leading to a general optimization method. This will contribute to a better understanding of functionality for nonequilibrium quantum many-body systems acting as thermal machines.
ACTA PHYSICA SINICA
(2021)
Article
Physics, Multidisciplinary
Jin-Min Liang, Shi-Jie Wei, Shao-Ming Fei
Summary: The article discusses the use of gradient descent in variational quantum algorithms and machine learning tasks, and its application in calculating molecular ground states, optimizing polynomial functions, and simulating nonequilibrium steady states of Markovian open quantum many-body systems. Additionally, it presents strategies for evaluating physical observables on nonequilibrium steady states and adapting the quantum gradient descent algorithm to solve linear algebra problems. Multiple detailed examples are provided to test the effectiveness of these algorithms.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2022)
Article
Physics, Particles & Fields
Daisuke Endo, Yuichi Fukazawa, Masataka Matsumoto, Shin Nakamura
Summary: We investigate phase transitions and critical phenomena in nonequilibrium steady states governed by an electric field using the D3/D7 model. In the presence of a charge density and electric field at finite temperatures, the system exhibits both first-order and second-order phase transitions. Our numerical analysis reveals that the critical exponents associated with the nonequilibrium phase transition in this model follow mean-field behavior.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Multidisciplinary
C. J. O. Reichhardt, A. del Campo, C. Reichhardt
Summary: This study investigates the non-equilibrium phase transitions of superconducting vortices and colloids, and demonstrates that the Kibble-Zurek mechanism is applicable to these transitions. The density of topological defects is measured, and it is found that the defect density scales according to a power law, with exponents falling in the directed percolation universality class. These results suggest that the Kibble-Zurek mechanism can be applied to a broader range of systems exhibiting absorbing phase transitions.
COMMUNICATIONS PHYSICS
(2022)
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
Quantum Science & Technology
Eric R. Anschuetz, Andreas Bauer, Bobak T. Kiani, Seth Lloyd
Summary: This study demonstrates that classical algorithms can efficiently simulate certain quantum algorithms by taking advantage of sufficiently restrictive symmetries. By using tensor-network methods to transform symmetry-equivariant operators to the block-diagonal Schur basis, the classical algorithms can calculate ground states and time-evolved expectation values for permutation-invariant Hamiltonians in polynomial time.