Article
Physics, Multidisciplinary
Niccolo Cocciaglia, Angelo Vulpiani, Giacomo Gradenigo
Summary: Recent numerical results indicate that the thermalization of Fourier modes can be achieved in a short time scale in the Toda model, despite its integrability and lack of chaos. This study provides numerical evidence that the irrelevant nature of chaos for thermalization is realized even in the simplest classical integrable system, such as the harmonic chain.
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
(2022)
Article
Physics, Fluids & Plasmas
Goran Nakerst, Masudul Haque
Summary: We investigate the relationship between chaos in a Bose-Hubbard system and its classical limit. By comparing quantum measures of chaos with classical measures, we find a strong correspondence between the two cases in terms of energy and interaction strength. Unlike strongly chaotic and integrable systems, the largest Lyapunov exponent is shown to be a multivalued function of energy.
Article
Physics, Multidisciplinary
Jean-Yves Desaules, Francesca Pietracaprina, Zlatko Papi, John Goold, Silvia Pappalardi
Summary: Recent experimental observation of weak ergodicity breaking in Rydberg atom quantum simulators has sparked interest in quantum many-body scars—eigenstates which evade thermalization at finite energy densities due to novel mechanisms that do not rely on integrability or protection by a global symmetry. In this Letter, we demonstrate that such exact many-body scars also possess extensive multipartite entanglement structure if they stem from an su(2) spectrum generating algebra. We show this analytically, through scaling of the quantum Fisher information, which is found to be superextensive for exact scarred eigenstates in contrast to generic thermal states. Furthermore, we numerically study signatures of multipartite entanglement in the PXP model of Rydberg atoms, showing that extensive quantum Fisher information density can be generated dynamically by performing a global quench experiment. Our results identify a rich multipartite correlation structure of scarred states with significant potential as a resource in quantum enhanced metrology.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Charlie Nation, Diego Porras
Summary: This study explores how quantum dynamics in a single excitation subspace deviates from predictions of the eigenstate thermalization hypothesis (ETH). By analyzing long-time fluctuations, two-point correlation functions, and out-of-time-ordered correlators, a new relation similar to ETH is derived. Additionally, the time-dependence of equilibrium decay is computed.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2022)
Article
Physics, Multidisciplinary
Piotr Sierant, Eduardo Gonzalez Lazo, Marcello Dalmonte, Antonello Scardicchio, Jakub Zakrzewski
Summary: In this study, the impact of quenched disorder on the dynamics of locally constrained quantum spin chains was investigated. Large-scale numerical experiments revealed no evidence of many-body localization even under high disorder. The analysis showed that quenched disorder terms in constrained systems act in two distinct and competing ways, preventing the system from entering into a regime of strong disorder and weak interaction where many-body localization occurs. Through observations in XY-type constrained models, it was further clarified that local quenched disorder terms must be represented as a series of nonlocal terms in unconstrained variables.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Yael Lebel, Lea F. Santos, Yevgeny Bar Lev
Summary: We investigate the chaotic properties of a large-spin XXZ chain with onsite disorder and a small number of excitations. Our findings reveal that the classical limit is chaotic, however, quantum chaos features are suppressed as the spin is increased. We explore methods to enhance chaos by introducing additional terms to the Hamiltonian. Interestingly, diagonal perturbations in the z-direction do not significantly enhance chaos, while off-diagonal perturbations restore chaoticity for large spins, requiring only three excitations to achieve strong level repulsion and ergodic eigenstates.
Article
Materials Science, Multidisciplinary
Bhaskar Mukherjee, Debasish Banerjee, K. Sengupta, Arnab Sen
Summary: The study reveals extensive fragmentation of the Hilbert space in this model, leading to a breakdown of thermalization despite the nonintegrable nature of the Hamiltonian. Different types of anomalous eigenstates are discussed, as well as the consequences of adding a magnetic field and a PXP term to the model.
Article
Materials Science, Multidisciplinary
Jimin L. Li, Dominic C. Rose, Juan P. Garrahan, David J. Luitz
Summary: This study investigates the effects of strong dissipation in quantum systems with a notion of locality, revealing the emergence of a manifold of metastable states due to variations in the dissipation strength. The findings are confirmed through a perturbative treatment using a simple model involving good and bad qubits with reduced dissipation.
Article
Multidisciplinary Sciences
Babak Sadigh, Luis Zepeda-Ruiz, Jonathan L. Belof
Summary: This study investigates the kinetic stabilization of metastable crystal phases during solidification processes through molecular dynamics simulations and crystal-liquid equilibria studies. It is found that metastable solid phases can coexist with the liquid phase at any given pressure, with nucleation rates into solid clusters in the liquid basin being practically calculable. The results indicate the possibility of kinetic instabilities overriding phase selections made during the nucleation stage, leading to the growth of metastable crystal phases under specific conditions.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Physics, Multidisciplinary
Marco Baldovin, Raffaele Marino, Angelo Vulpiani
Summary: In the framework of statistical mechanics, the properties of macroscopic systems are derived from the laws of their microscopic dynamics. The ergodic property, which assumes the equivalence between time averages and ensemble averages, is a key assumption in this process. This property has only been proven for a limited number of systems, but weak forms of it hold even in systems that are not ergodic at the microscopic scale when extensive observables are considered.
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
(2023)
Article
Physics, Multidisciplinary
Andreas Albrecht
Summary: This study explores the equilibration processes exhibited by the Adapted Caldeira-Leggett (ACL) model, a toy model used for quantum decoherence studies. The results demonstrate the role of dephasing in achieving equilibration in various situations. Although the model's size and other unphysical aspects limit the applicability of temperature and thermalization, certain basic aspects of thermalization can be realized under specific parameter values. The observed behaviors are linked to intrinsic properties of the global energy eigenstates, suggesting that they may be key ingredients for ergodic behavior in larger, more realistic systems.
Article
Chemistry, Multidisciplinary
Dandan Zhao, Jianrong Gao
Summary: This study presents a new theory that combines four types of interface kinetics with a generalized interface stability analysis, successfully describing the kinetics of dendrite growth in binary alloy solidification. The theory is validated by quantitative agreement with experimental results and shows a universal capability in describing dendrite growth in other alloy systems.
CRYSTAL GROWTH & DESIGN
(2022)
Article
Physics, Multidisciplinary
Shun-Yao Zhang, Dong Yuan, Thomas Iadecola, Shenglong Xu, Dong-Ling Deng
Summary: This study proposes a matrix-product-state algorithm to extract nonthermal excited eigenstates in quantum many-body scarred systems, and applies it to various models, providing a new approach for future investigations of nonthermal excitations.
PHYSICAL REVIEW LETTERS
(2023)
Article
Thermodynamics
Sushil Patel, Pradeep Reddy, Arvind Kumar
Summary: In laser spot welding, the rapid solidification process poses challenges in analyzing solidification, which generally occurs with non-equilibrium kinetics. A methodology for handling rapid solidification in laser spot welding is developed by solving transient conservation equations of mass, momentum and energy. The effect of undercooling and recalescence on melt pool dimension, temperature, solidification time and melt pool convection is investigated.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Physics, Multidisciplinary
Z. Chen, Y. Y. Tsui, M. Z. Mo, R. Fedosejevs, T. Ozaki, V. Recoules, P. A. Sterne, A. Ng
Summary: We report on the study of electron kinetics induced by intense femtosecond laser excitation of electrons in the 5d band of Au. Changes in electron system are observed from the temporal evolution of ac conductivity and conduction electron density. The results reveal an increase of electron thermalization time with excitation energy density, contrary to the Fermi-liquid behavior, and uncover the shortening of 5d hole lifetime with the increase of photoexcitation rates, providing valuable insights for understanding electron kinetics under extreme nonequilibrium conditions.
PHYSICAL REVIEW LETTERS
(2021)
Article
Mathematics, Applied
Dmitri Alexandrov, Peter K. Galenko
Summary: This article explores the hydrodynamic problem of oblique flow of a viscous incompressible fluid around the tip of a dendritic crystal. Approximate analytical solutions of Oseen's hydrodynamic equations in 2D and 3D cases using special curvilinear coordinates are obtained. The study reveals significant changes in the projections of fluid velocity with variations in flow slope and Reynolds number, and shows a limiting transition to previously known solutions for rectilinear fluid flow around a dendrite.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2022)
Article
Multidisciplinary Sciences
Peter K. Galenko, Junfeng Xu
Summary: This study investigates the formation mechanism of metastable solid phases in rapidly solidified eutectic systems. It proposes a diffusionless growth model to suppress eutectic decomposition and analyzes atomic diffusion in the growth of rod eutectics. A simplified calculating method for the Bessel function in the growth equation is also obtained, which can be applied to other rod eutectic growth models.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2022)
Article
Multidisciplinary Sciences
Yindong Fang, Peter K. Galenko, Dongmei Liu, Klaus Hack, Markus Rettenmayr, Stephanie Lippmann
Summary: The thermodynamic description of the fcc phase in the Al-Cu system has been revised to predict metastable fcc/liquid phase equilibria. Experimental and modeling results were used to determine solidus and liquidus concentrations and to validate the new description. The methodology can be applied to other alloy systems.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2022)
Article
Multidisciplinary Sciences
V Ankudinov, P. K. Galenko
Summary: This article presents a modified phase-field crystal model for simulating crystallization in colloidal and metallic systems. Through the study of chemical segregation dynamics, a structure diagram for the model is obtained, which shows qualitative agreement with the known equilibrium diagram based on thermodynamic functions.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2022)
Article
Multidisciplinary Sciences
E. Kharanzhevskiy, P. K. Galenko, M. Rettenmayr, S. Koch, R. Wonneberger, M. Zamoryanskaya, M. A. Yagovkina, D. A. Kirilenko, V. A. Bershtein, P. N. Yakushev, L. M. Egorova, K. N. Orekhova, V. G. Lebedev, A. Egorov, A. S. Senchenkov
Summary: This study investigates the structure formation during solidification of a Pd-Ni-Cu-P melt and finds that changes in heat transfer conditions lead to nonlinear changes in the structure characteristics. The experimental results show that a decrease in the cooling rate of the alloy increases the size, proportion, and composition of nanoinclusions in an amorphous matrix.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2022)
Review
Crystallography
Liubov Toropova, Peter K. Galenko, Dmitri Alexandrov
Summary: In this paper, a theory of stable dendritic growth in undercooled melts with conductive and convective boundary conditions is developed. The analytical theory is constructed by separately considering the conductive and convective mechanisms. The laws for total undercooling and selection criteria for stable growth mode are derived for each mechanism. The case of simultaneous occurrence of these heat and mass transfer mechanisms is also studied by combining the conductive and convective laws using power stitching functions. The generalized selection theory is validated through comparison with experimental data for Al24Ge76 and Ti45Al55 undercooled melts.
Article
Physics, Condensed Matter
Roberto E. Rozas, Vladimir Ankudinov, Peter K. Galenko
Summary: A revised study of the growth and melting of crystals in congruently melting Al50Ni50 alloy is carried out using molecular dynamics (MD) and phase field (PF) methods. The material properties are estimated using an embedded atom method (EAM) potential, which shows better agreement with experimental data compared to previous works. The kinetics of melting and solidification are quantitatively evaluated using the 'crystal-liquid interface velocity-undercooling' relationship, and the results are described by the kinetic PF model and hodograph equation.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Crystallography
Dmitri Alexandrov, Sergei Osipov, Peter K. Galenko, Liubov Toropova
Summary: This study investigates the stable growth mode of a single dendritic crystal solidifying in an undercooled ternary melt by considering a forced convective flow. The steady-state temperature, solute concentrations, and fluid velocity components are determined for both two- and three-dimensional problems. The stability criterion and the total undercooling balance are derived, taking into account the surface tension anisotropy at the solid-melt interface. The theoretical findings are compared with experimental data and phase-field modeling for the Ni98Zr1Al1 alloy.
Article
Materials Science, Multidisciplinary
P. K. Galenko, L. Toropova, D. Alexandrov, G. Phanikumar, H. Assadi, M. Reinartz, P. Paul, Y. Fang, S. Lippmann
Summary: According to thermodynamics, the crystal growth velocity is expected to increase monotonically with increasing undercooling. However, Al-rich Al-Ni alloys exhibit an anomalous solidification behavior where the solid-liquid interface velocity slows down as the undercooling increases. Recent microgravity experiments on the International Space Station (ISS) have confirmed this unexpected trend in solidification kinetics and observed multiple nucleation events.
Article
Crystallography
Yindong Fang, Dongmei Liu, Yongfu Zhu, Peter K. Galenko, Stephanie Lippmann
Summary: Electromagnetic levitation (EML) was used to study the velocity and morphology of the solidification front of metallic materials, and the limitations of EML technique were overcome by using high-speed mid-wavelength infrared cameras and photon detectors. The pattern formation of Al-based alloys was studied in detail, providing information on nucleation, phase selection, and the influence of convection.
Article
Crystallography
Dmitri V. Alexandrov, Peter K. Galenko, Liubov V. Toropova
Summary: A theory for crystal nucleation and growth with the recalescence front is developed, based on the saddle-point technique and the small parameter method. The theory shows a U-shaped behavior in the growth velocity-melt undercooling curve, with the upward branch representing growth dictated by heat transport and predominant crystal growth, and the downward branch demonstrating anomalous behavior caused by nucleation and attachment kinetics of the growing crystals. Experimental data from ground, reduced gravity parabolic flights, and microgravity conditions onboard the International Space Station support this U-shaped behavior.
Article
Physics, Multidisciplinary
P. K. Galenko
Summary: Convection has an impact on the primary crystalline structure, especially on the velocity and tip radius of dendrite crystals. This study focuses on the influence of convective flow on the spacing between neighboring crystals within the dendrite ensemble. A binary alloy's solidification process is considered in a stagnant boundary layer model under a imposed thermal gradient, which affects the microstructure and chemical microsegregation of crystals. The model takes into account the convective flow in the solution of the solute diffusion transport equation, deriving the chemical composition in the solidifying liquid and crystalline solid. The results of the model align with the Scheil-Brody-Flemings model, experimental data, and computational results.
EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS
(2023)
Article
Crystallography
Junfeng Xu, Peter K. Galenko
Summary: This paper presents a solidification growth model that combines the effect of eutectic transformation and off-eutectic composition, and discusses the influence of model and material parameters on solidification kinetics by comparing them with experimental data. The computational results show that the off-eutectic growth model agrees well with experimental data on the solidification kinetics of Ni-B and Ti-Si alloys.
Article
Crystallography
Tongzhuang Niu, Junfeng Xu, Zhirui Yao, Zengyun Jian, Peter K. Galenko
Summary: This article proposes a method for measuring and analyzing the volume and density changes in high-temperature alloy melts using high-speed photography and computer MATLAB program image analysis technology. These techniques will aid in understanding the variations in the volume and density of high-temperature melt samples during the phase transition process.
Article
Thermodynamics
Eugenya V. Makoveeva, Dmitri V. Alexandrov, Peter K. Galenko
Summary: A linear morphological stability analysis is conducted to investigate the solid-liquid phase interface during the solidification processes of a binary melt with convection. The study reveals the significant influence of convection intensity on stability and solidification, and identifies a criterion for concentration supercooling in steady-state solidification conditions. Various crystallization scenarios are defined based on the obtained dispersion relation and neutral stability curve.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Review
Physics, Multidisciplinary
Sebastian Mizera
Summary: This article discusses the mathematical properties and physical implications of scattering amplitudes, and traces these properties back to physics through simple scattering problems.
PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS
(2024)