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arXiv 2025年

作者： Coulter, Jennifer Rajkov, Bogdan Simoncelli, Michele Center for Computational Quantum Physics Flatiron Institute New York10010 United States Theory of Condensed Matter Group The Cavendish Laboratory University of Cambridge United Kingdom Department of Applied Physics and Applied Mathematics Columbia University New York United States

Non-diffusive, hydrodynamic-like transport of charge or heat has been observed in several materials, and recent, pioneering experiments have suggested the possible emergence of electron-phonon bifluids. Here we introduce the first-principles theory and computational framework to describe these phenomena, showing that the viscosity of electron-phonon bifluids is microscopically determined by composite "relaxon" electron-phonon excitations that also describe electron-phonon drag effects on thermoelectric transport coefficients. We show that these composite excitations emerge from the microscopic coupled electron-phonon Boltzmann transport equation, and demonstrate that the latter can be coarse-grained into a set of mesoscopic Viscous Thermoelectric Equations (VTE). The VTE unify the established hydrodynamic equation for electrons derived by Gurzhi [Sov. Phys. Usp. 11 1968], and the recently developed Viscous Heat Equations for phonons [PRX 10, 2020], while also extending them to cover the mixed electron-phonon bifluid regime. We employ this framework to elucidate from first principles the conditions under which electron and phonon fluids can coexist and mix, as well as to rationalize experimental signatures of electron-phonon drag in graphite. © 2025, CC BY-NC-ND.

关键词： Hydrodynamics

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On the Nonlinear Growth of Multiphase Richtmyer-Meshkov Instability in Dilute Gas-Particles Flow

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Chinese physics Letters 2020年第1期37卷 24-28页

作者： Huan Zheng Qian Chen Baoqing Meng Junsheng Zeng Baolin Tian Institute of Applied Physics and Computational Mathematics Beijing 100094 College of Engineering Peking UniversityBeijing 100871

We discuss evolutions of nonlinear features in Richtmyer-Meshkov instability(RMI)f which are known as spikes and *** single-phase RMI,the nonlinear growth has been extensively studied but the relevant investigation in multiphase RMI is ***,we illustrate the dynamic coupling behaviors between gas phase and particle phase and then analyze the growth of the nonlinear features theoretically.A universal model is proposed to describe the nonlinear finger(spike and bubble)growth velocity qualitatively in multiphase *** the effects of gas and particles have been taken into consideration in this ***,we derive the analytical expressions of the nonlinear growth model in limit cases(equilibrium How and frozen How).A novel compressible multiphase particle-in-cell(CMP-PIC)method is used to validate the applicability of this *** finger growth velocity matches well with our *** present study reveals that particle volume fraction,particle density and Stokes number are the three key factors,which dominate the interphase momentum exchange and further induce the unique property of multiphase RMI.

关键词： multiphase nonlinear Nonlinear

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THE SPACE-TIME ESTIMATES FOR THE SCHRÖDINGER EQUATION

arXiv

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arXiv 2024年

作者： Li, Junfeng Miao, Changxing Yu, Ankang School of Mathematical Sciences Dalian University of Technology LN Dalian116024 China Institute of Applied Physics and Computational Mathematics Beijing100088 China

In this paper, we studied the space-time estimates for the solution to the Schrödinger equation. By polynomial partitioning, induction arguments, bilinear to linear arguments and broad norm estimates, we set up several maximal estimates for the Schrödinger equation with high frequency input data. By these maximal estimates we obtain the sharp global space-time estimate when n = 2 and improve the known results in the critical cases when n ≥ 3. The maximal estimate for n = 2 is also used to extend the results of the local space-time estimates for the solution to the Schrödinger equation. © 2024, CC0.

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High-Flux Neutron Generator Based on Laser-Driven Collisionless Shock Acceleration

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Physical Review Letters 2023年第2期131卷 025101-025101页

作者： Y. L. Yao S. K. He Z. Lei T. Ye Y. Xie Z. G. Deng B. Cui W. Qi L. Yang S. P. Zhu X. T. He W. M. Zhou B. Qiao Center for Applied Physics and Technology HEDPS and State Key Laboratory of Nuclear Physics and Technology School of Physics Peking University Beijing 100871 China Science and Technology on Plasma Physics Laboratory Research Center of Laser Fusion China Academy of Engineering Physics (CAEP) Mianyang 621900 China Institute of Applied Physics and Computational Mathematics Beijing 100094 China Frontiers Science Center for Nano-optoelectronic Peking University Beijing 100094 China

A novel compact high-flux neutron generator with a pitcher-catcher configuration based on laser-driven collisionless shock acceleration (CSA) is proposed and experimentally verified. Different from those that previously relied on target normal sheath acceleration (TNSA), CSA in nature favors not only acceleration of deuterons (instead of hydrogen contaminants) but also increasing of the number of deuterons in the high-energy range, therefore having great advantages for production of high-flux neutron source. The proof-of-principle experiment has observed a typical CSA plateau feature from 2 to 6 MeV in deuteron energy spectrum and measured a forward neutron flux with yield 6.6×107 n/sr from the LiF catcher target, an order of magnitude higher than the compared TNSA case, where the laser intensity is 1019 W/cm2. Self-consistent simulations have reproduced the experimental results and predicted that a high-flux forward neutron source with yield up to 5×1010 n/sr can be obtained when laser intensity increases to 1021 W/cm2 under the same laser energy.

关键词： High-energy-density plasmas Laser driven ion acceleration Laser-plasma interactions Neutron physics Nuclear reactions Neutrons Multiscale modeling Nuclear data analysis & compilation

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Single- and double-ionization processes of antiproton-helium and antiproton–molecular hydrogen collisions in the keV energy range

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Physical Review A 2023年第1期107卷 012808-012808页

作者： C. C. Jia T. Kirchner J. W. Gao Y. Wu J. G. Wang N. Sisourat Key Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing 100088 China Laboratoire de Chimie Physique-Matière et Rayonnement Sorbonne Université CNRS 75005 Paris France Department of Physics and Astronomy York University Toronto Ontario Canada M3J 1P3 School of Physics Hangzhou Normal University Hangzhou 311121 China

We report on an ab initio model to describe single- and double-ionization processes in antiproton collisions with atoms and molecules. Our model is based on a fully correlated close-coupling approach and a Dyson orbital analysis. Furthermore, we employ the concept of a correlation integral in order to quantify and gain insights into the effects of electronic correlation on the ionization processes. Our model is applied to the prototype antiproton-helium and antiproton–molecular hydrogen collision systems in the keV energy range.

关键词： Atomic & molecular collisions Electronic excitation & ionization

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Dual-site parallel binding ligands for enhanced perovskite solar cell efficiency

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Journal of Energy Chemistry 2025年第06期 112-120页

作者： Zhiqian Yang Yingke Ren Li'e Mo Mengting Han Aiqing Sun Zhaoqian Li Hong Zhang Yong Ding Yang Huang Linhua Hu Key Laboratory of Photovoltaic and Energy Conservation Materials CAS Institute of Solid State Physics Hefei Institutes of Physical Science Chinese Academy of Sciences University of Science and Technology of China College of Science Hebei University of Science and Technology Hebei Computational Optical Imaging and Photoelectric Detection Technology Innovation Center Hebei International Joint Research Center for Computational Optical Imaging and Intelligent Sensing School of Mathematics and Physics Science and Engineering Hebei University of Engineering State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Anhui Institute of Innovation for Industrial Technology

Perovskite solar cells（PSCs） are promising in the field of photovoltaics but are hindered by surface defects and ***,the energetic losses occurring at the interfaces between the perovskite and the charge transport layers often lead to reduced power conversion efficiency（PCE）.Surface treatment is an effective strategy but the passivating ligands usually bind with a single active *** resulted dense packing of resistive passivators perpendicular to the surface is detrimental to charge ***,we present a passivator that can bind to two neighboring lead（Ⅱ） ion(Pb2+) defect sites simultaneously with an aligned parallel mode to the perovskite surface,effectively suppressing the surface trap density and preventing the *** target device fulfills a PCE of 25.1% and maintains over 85% of the initial efficiency after 800 h of exposure to a relative humidity（RH） of 65% ± 5%.

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Anisotropic high-Tc superconductivity above 90 K in hole-doped boron-nitrogen clathrates at ambient pressure

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Physical Review B 2025年第9期111卷 094520-094520页

作者： Yu-Lin Han Kai-Yue Jiang Bao-Tian Wang Ping Zhang Hong-Yan Lu School of Physics and Physical Engineering Qufu Normal University Qufu 273165 China Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Spallation Neutron Source Science Center Dongguan 523803 China Institute of Applied Physics and Computational Mathematics Beijing 100088 China

Breakthroughs in near-room-temperature superconductivity within clathrate hydrides underscore the effectiveness of theory-driven approaches to designing high-Tc superconductors. However, superconductivity in these clathrate hydrides has not been realized at low or ambient pressures. To explore phonon-mediated superconductors with Tc exceeding the liquid-nitrogen temperature under ambient pressure, this study investigates the crystal structure, metallization, electron-phonon coupling, and anisotropic superconducting behavior in hole-doped (BN)6 and (BN)5 clathrates, with configurations akin to CaH6 and LaH10, utilizing first-principles calculations in junction with Wannier interpolation technique. By solving the fully anisotropic Migdal-Eliashberg equations, this work reveals a positive correlation between Tc and hole-doping levels, with the highest Tc approximately 32 K and 96 K in hole-doped (BN)6 and (BN)5, respectively, and both with single anisotropic energy gap nature. The high-Tc superconductivity in B-N clathrates arises from two primary factors: the enhanced density of states at the Fermi level and the presence of strong B-N sp3-hybridized covalent σ-bonding bands. These insights provide a new perspective for revealing the superconductivity of B-N clathrates from an anisotropic perspective and offer valuable avenues for inducing high-Tc superconductors at ambient conditions.

关键词： Energy gap

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Dispersive estimates for time and space fractional Schrödinger equations

Dispersive estimates for time and space fractional Schrödin...

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作者： Su, Xiaoyan Zhao, Shiliang Li, Miao Institute of Applied Physics and Computational Mathematics Beijing100094 China Department of Mathematics Sichuan University Chengdu610064 China

In this paper, we consider the Cauchy problem for the fractional Schrödinger equation (Formula presented.) with 0 0. We establish the dispersive estimates by a carefully study of the Mittag-Leffler functions and give some applications as well. In particular, we prove that the decay rates are sharp. © 2019 John Wiley & Sons, Ltd.

关键词： Decay (organic)

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Superconductivity in Ca-intercalated bilayer graphene: C2CaC2

arXiv

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arXiv 2023年

作者： Tan, Jin-Han Wang, Hao Chen, Ying-Jie Jiao, Na Zheng, Meng-Meng Lu, Hong-Yan Zhang, Ping School of Physics and Physical Engineering Qufu Normal University Qufu273165 China Institute of Applied Physics and Computational Mathematics Beijing100088 China

The deposition and intercalation of metal atoms can induce superconductivity in monolayer and bilayer graphenes. For example, it has been experimentally proved that Li-deposited graphene is a superconductor with critical temperature Tc of 5.9 K, Ca-intercalated bilayer graphene C6CaC6 and K-intercalated epitaxial bilayer graphene C8KC8 are superconductors with Tc of 2-4 K and 3.6 K, respectively. However, the Tc of them are relatively low. To obtain higher Tc in graphene-based superconductors, here we predict a new Ca-intercalated bilayer graphene C2CaC2, which shows higher Ca concentration than the C6CaC6. It is proved to be thermodynamically and dynamically stable. The electronic structure, electron-phonon coupling (EPC) and superconductivity of C2CaC2 are investigated based on first-principles calculations. The EPC of C2CaC2 mainly comes from the coupling between the electrons of C-pz orbital and the high- and low-frequency vibration modes of C atoms. The calculated EPC constant λ of C2CaC2 is 0.75, and the superconducting Tc is 18.9 K, which is much higher than other metal-intercalated bilayer graphenes. By further applying -4% biaxial compressive strain to C2CaC2, the Tc can be boosted to 26.6 K. Thus, the predicted C2CaC2 provides a new platform for realizing superconductivity with the highest Tc in bilayer graphenes. Copyright © 2023, The Authors. All rights reserved.

关键词： Graphene

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Random-walk shielding-potential viscosity model for warm dense metals

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Physical Review E 2022年第1期106卷 014142-014142页

作者： Yuqing Cheng Haifeng Liu Yong Hou Xujun Meng Qiong Li Yu Liu Xingyu Gao Jianmin Yuan Haifeng Song Jianguo Wang School of Mathematics and Physics University of Science and Technology Beijing Beijing 100083 China Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing 100094 China Department of Physics College of Liberal Arts and Sciences National University of Defense Technology Changsha 410073 China Graduate School China Academy of Engineering Physics Beijing 100193 China

We develop a model, called the “random-walk shielding-potential viscosity model” (RWSP-VM) that introduces the statistics of random-walk ions and the Debye shielding effect to describe the viscosities of warm dense metals. The viscosities of several metals with low to high atomic numbers (Be, Al, Fe, and U) are calculated using the analytical expression of RWSP-VM. Additionally, we simulate the viscosities of Fe and Be by employing the Langevin molecular dynamics (MD) and classical MD, while the MD data for Al and U are obtained from a previous work. The results of the RWSP-VM are in good agreement with the MD results, which validates the proposed model. Furthermore, we compare the RWSP-VM with the one-component plasma model and Yukawa viscosity model and show that the three models yield results in excellent agreement with each other in the regime where the RWSP-VM is applicable. These results indicate that the RWSP-VM is a universal, accurate, and highly efficient model for calculating the viscosity of metals in the warm dense state. The code of the proposed RWSP-VM is provided, and it is envisaged that it will have broad application prospects in numerous fields.

关键词： Classical statistical mechanics Classical transport High-energy-density plasmas Random walks Ionic fluids Liquid metals Metals First-principles calculations Molecular dynamics

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