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Dynamic mode decomposition of nonequilibrium electron-phonon dynamics:accelerating the firstprinciples real-time Boltzmann equation

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npj Computational Materials 2024年第1期10卷 1970-1977页

作者： Ivan Maliyov Jia Yin Jia Yao Chao Yang Marco Bernardi Department of Applied Physics and Materials Science California Institute of TechnologyPasadenaCA 91125USA Applied Mathematics and Computational Research Division Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Department of Physics California Institute of TechnologyPasadenaCA 91125USA

Nonequilibrium dynamics governed by electron–phonon(e-ph)interactions plays a key role in electronic devices and spectroscopies and is central to understanding electronic excitations in *** real-time Boltzmann transport equation(rt-BTE)with collision processes computed from first principles can describe the coupled dynamics of electrons and atomic vibrations(phonons).Yet,a bottleneck of these simulations is the calculation of e–ph scattering integrals on dense momentum grids at each time *** we show a data-driven approach based on dynamic mode decomposition(DMD)that can accelerate the time propagation of the rt-BTE and identify dominant electronic *** apply this approach to two case studies,high-field charge transport and ultrafast excited electron *** both cases,simulating only a short time window of~10%of the dynamics suffices to predict the dynamics from initial excitation to steady state using DMD *** of the momentum-space modes extracted from DMD sheds light on the microscopic mechanisms governing electron relaxation to a steady state or *** combination of accuracy and efficiency makes our DMD-based method a valuable tool for investigating ultrafast dynamics in a wide range of materials.

关键词： materials dynamics phonon

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Faithful geometric measures for genuine tripartite entanglement

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Physical Review A 2024年第1期110卷 L010402-L010402页

作者： Xiaozhen Ge Lijun Liu Yong Wang Yu Xiang Guofeng Zhang Li Li Shuming Cheng Department of Control Science and Engineering Department of Applied Mathematics The Department of Mathematics and Computer Science State Key Laboratory for Mesoscopic Physics School of Physics Frontiers Science Center for Nano-optoelectronics and Collaborative Innovation Center of Quantum Matter Shanghai Institute of Intelligent Science and Technology Institute for Advanced Study

We present a faithful geometric picture for genuine tripartite entanglement of discrete, continuous, and hybrid quantum systems. We first find that the triangle relation Ei|jkα≤Ej|ikα+Ek|ijα holds for all subadditive bipartite entanglement measure E, all permutations under parties i,j,k, all α∈[0,1], and all pure tripartite states. Then, we rigorously prove that the nonobtuse triangle area, enclosed by side Eα with 0<α≤1/2, is a measure for genuine tripartite entanglement. Finally, it is significantly strengthened for qubits that given a set of subadditive and nonsubadditive measures, some state is always found to violate the triangle relation for any α>1, and the triangle area is not a measure for any α>1/2. Our results pave the way to study discrete and continuous multipartite entanglement within a unified framework.

关键词： Entanglement measures Quantum correlations in quantum information Quantum correlations, foundations & formalism Resource theories

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Stretched non-negative matrix factorization

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npj Computational Materials 2024年第1期10卷 1248-1262页

作者： Ran Gu Yevgeny Rakita Ling Lan Zach Thatcher Gabrielle E.Kamm Daniel O’Nolan Brennan Mcbride Allison Wustrow James R.Neilson Karena W.Chapman Qiang Du Simon J.L.Billinge NITFID School of Statistics and Data ScienceNankai UniversityTianjinChina Department of Applied Physics and Applied Mathematics Fu Foundation School of Engineering&Applied SciencesColumbia UniversityNew YorkNYUSA Department of Chemistry Stony Brook UniversityStony BrookNYUSA Department of Chemistry Colorado State UniversityFort CollinsCOUSA

A novel algorithm,STRETCHEDNMF,is introduced for non-negative matrix factorization(NMF),accounting for signal stretching along the independent variable’s *** addresses signal variability caused by stretching,proving beneficial for analyzing data such as powder diffraction at varying *** approach provides a more meaningful decomposition,particularly when the component signals resemble those from chemical components in the *** STRETCHEDNMF model introduces a stretching factor to accommodate signal expansion,solved using discretization and Block Coordinate Descent *** experimental results indicate that the STRETCHEDNMF model outperforms conventional NMF for datasets exhibiting such *** enhanced version,SPARSE-STRETCHEDNMF,optimized for powder diffraction data from crystalline materials,leverages signal sparsity for accurate extraction,especially with small *** results showcase its effectiveness in analyzing diffraction data,including success in real-time chemical reaction experiments.

关键词： signal stretching matrix

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Spectroscopy and molecule opacity investigation on excited states of SiS

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Chinese physics B 2024年第5期33卷 381-387页

作者：李瑞吕浩男桑纪群刘晓华梁桂颖吴勇 College of Teacher Education Qiqihar UniversityQiqihar 161006China National Key Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Department of Physics College of ScienceQiqihar UniversityQiqihar 161006China School of Data Science and Artificial Intelligence Jilin Engineering Normal UniversityChangchun 130052China HEDPS Center for Applied Physics and TechnologyPeking UniversityBeijing 100084China

The SiS molecule,which plays a significant role in space,has attracted a great deal of attention for many *** to complex interactions among its low-lying electronic states,precise information regarding the molecular structure of SiS is *** obtain accurate information about the structure of its excited states,the high-precision multireference configuration interaction(MRCI)method has been *** method is used to calculate the potential energy curves(PECs)of the 18Λ–S states corresponding to the lowest dissociation limit of *** core–valence correlation effect,Davidson’s correction and the scalar relativistic effect are also included to guarantee the precision of the MRCI *** on the calculated PECs,the spectroscopic constants of quasi-bound and bound electronic states are calculated and they are in accordance with previous experimental *** transition dipole moments(TDMs)and dipole moments(DMs)are determined by the MRCI *** addition,the abrupt variations of the DMs for the 1^(5)Σ^(+)and 2^(5)Σ^(+)states at the avoided crossing point are attributed to the variation of the electronic *** opacity of SiS at a pressure of 100 atms is presented across a series of *** increasing temperature,the expanding population of excited states blurs the band boundaries.

关键词： SiS opacity excited state spectroscopic constant configuration interaction

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Phase-field simulations of the effect of temperature and interface for zirconiumδ-hydrides

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Chinese physics B 2024年第4期33卷 701-710页

作者：陈子航盛杰刘瑜施小明黄厚兵许可王越超武帅孙博刘海风宋海峰 School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Advanced Research Institute of Multidisciplinary Science Beijing Institute of TechnologyBeijing 100081China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Department of Physics University of Science and Technology BeijingBeijing 100083China

Hydride precipitation in zirconium cladding materials can damage their integrity and *** temperature and material defects have a significant effect on the dynamic growth of *** this study,we have developed a phasefield model based on the assumption of elastic behaviour within a specific temperature range(613 K-653 K).This model allows us to study the influence of temperature and interfacial effects on the morphology,stress,and average growth rate of zirconium *** results suggest that changes in temperature and interfacial energy influence the length-to-thickness ratio and average growth rate of the hydride *** ultimate determinant of hydride orientation is the loss of interfacial coherency,primarily induced by interfacial dislocation defects and quantifiable by the mismatch degree *** escalation in interfacial coherency loss leads to a transition of hydride growth from horizontal to vertical,accompanied by the onset of redirection ***,redirection occurs at a critical mismatch level,denoted as qc,and remains unaffected by variations in temperature and interfacial ***,this redirection leads to an increase in the maximum stress,which may influence the direction of hydride crack *** research highlights the importance of interfacial coherency and provides valuable insights into the morphology and growth kinetics of hydrides in zirconium alloys.

关键词： zirconium hydride phase-field method temperature effect mismatch degree

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Point process microstructural model of metallic thin films with implications for coarsening

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npj Computational Materials 2023年第1期9卷 2074-2082页

作者： J.M.Rickman K.Barmak Y.Epshteyn C.Liu Department of Materials Science and Engineering Lehigh UniversityBethlehemPA 18015USA Department of Physics Lehigh UniversityBethlehemPA 18015USA Department of Applied Physics and Applied Mathematics Columbia UniversityNew YorkNY 10027USA Department of Mathematics The University of UtahSalt Lake CityUT 84112USA Department of Applied Mathematics Illinois Institute of TechnologyChicagoIL 60616USA

We develop a thin-film microstructural model that represents structural markers(i.e.,triple junctions in the two-dimensional projections of the structure of films with columnar grains)in terms of a stochastic,marked point process and the microstructure itself in terms of a grain-boundary *** advantage of this representation is that it is conveniently applicable to the characterization of microstructures obtained from crystal orientation mapping,leading to a picture of an ensemble of interacting triple junctions,while providing results that inform grain-growth models with experimental *** specifically,calculated quantities such as pair,partial pair and mark correlation functions,along with the microstructural mutual information(entropy),highlight effective triple junction interactions that dictate microstructural *** validate this approach,we characterize microstructures from Al thin films via crystal orientation mapping and formulate an approach,akin to classical density functional theory,to describe grain growth that embodies triple-junction interactions.

关键词： grain microstructure process

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Vibronic effect study of ^(1)A_(2) state of H_(2)O and D_(2)O

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Chinese physics B 2024年第5期33卷 395-399页

作者：张倍源王礼涵朱剑辉徐卫青马子茹赵小利吴勇朱林繁 Department of Modern Physics University of Science and Technology of ChinaHefei 230026China Center for Transformative Science ShanghaiTech UniversityShanghai 201210China Department of Physics Yantai UniversityYantai 264005China Institute of Applied Physics and Computational Mathematics Beijing 100088China School of Physics and Information Technology Shaanxi Normal UniversityXi'an 710119China HEDPS Center for Applied Physics and TechnologyPeking UniversityBeijing 100084China

The generalized oscillator strengths of the dipole-forbidden excitations of the ^(1)A_(2) of H_(2)O and D_(2)O were calculated with the time dependent density functional theory,by taking into account the vibronic *** is found that the vibronic effect converts the dipole-forbidden excitation of the ^(1)A_(2) into a dipole-allowed one,which enhances the intensities of the corresponding generalized oscillator strength in the small squared momentum transfer *** present investigation shows that the vibronic effect of H_(2)O is slightly stronger than that of D_(2)O,which exhibits a clear isotopic effect.

关键词： water heavy water generalized oscillator strength vibronic effect isotope effect

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Resonant Scattering of Gravitational Waves with Electromagnetic Waves

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Chinese physics Letters 2023年第10期40卷 1-5页

作者：闫若帝刘润球 Department of Physics Beijing Normal UniversityBeijing 100875China Institute of Applied Mathematics Morningside Center of MathematicsLSSCAcademy of Mathematics and System ScienceChinese Academy of SciencesBeijing 100190China.

A certain class of exact solutions of Einstein Maxwell spacetime in general relativity is discussed to demonstrate that at the level of theory,when certain parametric resonance condition is met,the interaction of electromagnetic field with a gravitational wave will display certain Lyapunov instability and lead to exponential amplification of a gravitational wave train described by certain Newman-Penrose component of the Weyl *** some way akin to a free electron laser in electromagnetic theory,by the conversion of electromagnetic energy into gravitational energy in a coherent way,the feasibility of generating a pulsed-laser-like intense beam of gravitational wave is displayed.

关键词： Penrose generating exponential

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Ab initio study of the stability and elasticity of brucite

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Physical Review B 2024年第21期109卷 214103-214103页

作者： Hongjin Wang Chenxing Luo Renata M. Wentzcovitch Department of Applied Physics and Applied Mathematics Department of Earth and Environmental Sciences Lamont–Doherty Earth Observatory Data Science Institute

Brucite [Mg(OH)2] is a mineral of great interest owing to its various applications and roles in geological processes. Its structure, behavior under different conditions, and unique properties have been the subject of numerous studies and persistent debate. As a stable hydrous phase in subduction zones, its elastic anisotropy can significantly contribute to the seismological properties of these regions. We performed ab initio calculations to investigate brucite's stability, elasticity, and acoustic velocities. We tested several exchange-correlation functionals and managed to obtain stable phonons for the P3¯ phase with r2SCAN at all relevant pressures up to the mantle transition zone. We show that r2SCAN performs very well in brucite, reproducing the experimental equation of state and several key structure parameters related to hydrogen positions. The room-temperature elasticity results in P3¯ reproduces the experimental results at ambient pressure. These results, together with the stable phonon dispersion of P3¯ at all relevant pressures, indicate P3¯ is the stable candidate phase not only at elevated pressures but also at ambient conditions. The success of r2SCAN in brucite suggests this functional should be suitable for other challenging layer-structured minerals, e.g., serpentines, of great geophysical significance.

关键词： Hydrogen bonds Phonons Minerals First-principles calculations Meta-GGA

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Elasticity and acoustic velocities of δ−AlOOH at extreme conditions: A methodology assessment

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Physical Review Materials 2024年第10期8卷 103601页

作者： Chenxing Luo (罗晨星) Yang Sun (孙阳) Renata M. Wentzcovitch Department of Applied Physics and Applied Mathematics Department of Physics Department of Earth and Environmental Sciences Lamont–Doherty Earth Observatory Data Science Institute Center for Computational Quantum Physics

Hydrous phases play a fundamental role in the deep-water cycle on Earth. Understanding their stability and thermoelastic properties is essential for constraining their abundance using seismic tomography. However, determining their elastic properties at extreme conditions is notoriously challenging. The challenges stem from the complex behavior of hydrogen bonds under high pressures and temperatures (P,Ts). In this study, we evaluate how advanced molecular dynamics simulation techniques can address these challenges by investigating the adiabatic elasticity and acoustic velocities of δ−AlOOH, a critical and prototypical high-pressure hydrous phase. We compared the performances of three methods to assess their viability and accuracy. The thermoelastic tensor was computed up to 140 GPa and temperatures up to 2700 K using molecular dynamics with a DeePMD machine-learning interatomic potential based on the SCAN meta-GGA functional. The excellent agreement with ambient condition single-crystal ultrasound measurements and the correct description of velocity changes induced by H-bond disorder-symmetrization transition observed at 10 GPa in Brillouin scattering measurements underscores the accuracy and efficacy of our approach.

关键词： Elasticity Geophysics High-pressure studies Hydrogen bonds Disordered systems Minerals Molecular dynamics

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