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Dynamical quantum phase transition in XY chains with the Dzyaloshinskii-Moriya and XZY-YZX three-site interactions

Chinese Physics B 2022年第6期31卷 260-266页

作者： Kaiyuan Cao Ming Zhong Peiqing Tong Department of Physics and Institute of Theoretical Physics Nanjing Normal UniversityNanjing 210023China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal UniversityNanjing 210023China

We study the dynamical quantum phase transitions(DQPTs)in the XY chains with the Dzyaloshinskii-Moriya interaction and the XZY-YZX type of three-site interaction after a sudden *** the models can be mapped to the spinless free fermion models by the Jordan-Wigner and Bogoliubov transformations with the form■where the quasiparticle excitation spectraεkmay be smaller than 0 for some k and are asymmetrical■It is found that the factors of Loschmidt echo equal 1 for some k corresponding to the quasiparticle excitation spectra of the pre-quench Hamiltonian satisfyingε_(k)·ε_(-k)<0,when the quench is from the gapless *** considering the quench from different ground states,we obtain the conditions for the occurrence of DQPTs for the general XY chains with gapless phase,and find that the DQPTs may not occur in the quench across the quantum phase transitions regardless of whether the quench is from the gapless phase to gapped phase or from the gapped phase to gapless *** is different from the DQPTs in the case of quench from the gapped phase to gapped phase,in which the DQPTs will always ***,we analyze the different reasons for the absence of DQPTs in the quench from the gapless phase and the gapped *** conclusion can also be extended to the general quantum spin chains.

关键词： dynamical quantum phase transition gapless phase asymmetry excitation spectra

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Lattice thermal conductivity switching via structural phase transition in ferromagnetic VI_(3)

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Chinese Physics B 2023年第5期32卷 20-26页

作者：吴超刘晨晗 Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093China Micro-and Nano-scale Thermal Measurement and Thermal Management Laboratory School of Energy and Mechanical EngineeringNanjing Normal UniversityNanjing 210023China Jiangsu Key Laboratory for Numerical Simulation of Large-Scale Complex Systems Nanjing Normal UniversityNanjing 210023China Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments School of Mechanical EngineeringSoutheast UniversityNanjing 211100China

The realization of reversible thermal conductivity through ferromagnetic ordering can improve the heat management and energy efficiency in magnetic materials-based ***_(3),as a new layered ferromagnetic semiconductor,exhibits a structural phase transition from monoclinic(C2/m)to rhombohedral(R3^(-))phase as temperature decreases,making it a suitable platform to investigate thermal switching in magnetic phase transition *** work reveals that the thermal switching ratio of VI_(3)can reach 3.9 along the *** properties analysis indicates that the C2/m structure is stiffer than the R^(-)one,causing the larger phonon velocity in C2/m ***,due to the fewer phonon branches in C2/m phase,the number of phonon–phonon scattering channels in C2/m phase is smaller compared to that of R^(-)*** the larger phonon velocity and the longer phonon lifetime lead to larger lattice thermal conductivity in C2/m *** study uncovers the mechanical and thermal properties of VI_(3),which provides useful guides for designing magnetic materials-based devices such as thermal switch.

关键词： thermal switching ferromagnetic ordering phonons

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Effects of phonon bandgap on phonon-phonon scattering in ultrahigh thermal conductivityθ-phase TaN

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Chinese Physics B 2023年第4期32卷 543-548页

Phonon bandgap typically has a significant effect on phonon-phonon scattering *** this work,the effects of mass modified phonon bandgap inθ-phase Ta N are systemically investigated by the means of first-principles calculations with linearized Boltzmann transport *** detailed calculations,we find that phonon bandgap has a significant effect on three-phonon process while exhibits a much weaker effect on four-phonon *** reason for the ultrahigh thermal conductivity ofθ-phase Ta N is the long lifetime of phonons including both three-phonon and four-phonon processes,which originates from the weak phonon anharmonicity and large phonon bandgap-induced small phonon-phonon scattering phase *** work advances the understanding of phonon bandgap effects on phonon transport.

关键词： ultrahigh thermal conductivity phonon-phonon scattering phase space first-principles calculation phonon bandgap

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Resonance contributions fromχ_(c0)in charmless three-body hadronic B meson decays

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Chinese Physics C 2023年第4期47卷 148-154页

作者：张亚兰王超林毅肖振军 Faculty of Mathematics and Physics Huaiyin Institute of TechnologyHuaian 223200China Department of Physics and Institute of Theoretical Physics Nanjing Normal UniversityNanjing 210023China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal UniversityNanjing 210023China

Within the framework of perturbative QCD factorization,we investigate the nonfactorizable contributions to the factorization-forbidden quasi-two-body decays B_((s))→h_((χ)_(c0))→hπ^(+)π^(-)(K^(+)K^(-))with h=π,*** compare our predicted branching ratios for the B_(()(s))→K_(χc0)→Kπ^(+)π-(K^(+)K^(-))decay with available experiment data as well as predictions by other theoretical *** branching ratios of these decays are consistent with data and other theoretical ***,in the Cabibbo-suppressed decays B_((s))→h_((χ)_(c0))→hπ^(+)π^(-)(K^(+)K^(-))with h=K^(0),π,the values of the branching ratios are of the order of 10^(-7)and 10^(-8).The ratio R_((χ)_(c0))between the decays B^(+)→π^(+)χ_(c0)→π^(+)π^(+)π^(-)and B^(+)→K^(+)χc0→K^(+)π^(+)π^(-)and the distribution of branching ratios for different decay modes in invariant mass are considered in this study.

关键词： three-body B meson decays resonance contributions perturbative QCD factorization approach

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Arbitrarily High-Order Energy-Preserving Schemes for the Camassa-Holm Equation Based on the Quadratic Auxiliary Variable Approach

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Advances in Applied Mathematics and Mechanics 2023年第5期15卷 1233-1255页

作者： Yuezheng Gong Qi Hong Chunwu Wang Yushun Wang School of Mathematics Nanjing University of Aeronautics and AstronauticsNanjingJiangsu 211106China Key Laboratory of Mathematical Modelling and High Performance Computing of Air Vehicles(NUAA) MIITNanjingJiangsu 211106China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems School of Mathematical SciencesNanjing Normal UniversityNanjingJiangsu 210023China

In this paper,we present a quadratic auxiliary variable(QAV)technique to develop a novel class of arbitrarily high-order energy-preserving algorithms for the Camassa-Holm *** QAV approach is first utilized to transform the original equation into a reformulated QAV system with a consistent initial *** the reformulated QAV system is discretized by applying the Fourier pseudo-spectral method in space and the symplectic Runge-Kutta methods in time,which arrives at a class of fully discrete *** the consistent initial condition,they can be rewritten as a new fully discrete system by eliminating the introduced auxiliary variable,which is rigorously proved to be energy-preserving and *** numerical experiments are conducted to confirm the expected order of accuracy,conservative property and efficiency of the proposed *** presented numerical strategy makes it possible to directly apply a special class of Runge-Kutta methods to develop energy-preserving algorithms for a general conservative system with any polynomial energy.

关键词： Camassa-Holm equation quadratic auxiliary variable high-order energy-preserving schemes symplectic Runge-Kutta methods

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The co-evolution of East Asian subtropical westerly jet and East Asian summer monsoon during different time periods in the Holocene and its influence on precipitation patterns in China

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Science China Earth Sciences 2025年第4期68卷 1100-1115页

作者： Yawen LIU Mi YAN Jian LIU Sumin WANG Zhengyu LIU Liang NING Ziyi WANG Key Laboratory for Virtual Geographic Environment Ministry of Education/State Key Laboratory Cultivation Base of Geographical Environment Evolution and Regional Response/Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and ApplicationSchool of GeographyNanjing Normal UniversityNanjing210023China Jiangsu Provincial Key Laboratory for Numerical Simulation of Large Scale Complex Systems School of Mathematical SciencesNanjing Normal UniversityNanjing210023China Nanjing Institute of Geography and Limnology Chinese Academy of SciencesNanjing210008China Department of Geography The Ohio State UniversityColumbusOH43210USA

Generally,the interaction between the East Asian subtropical westerly jet(EASWJ)and the East Asian summer monsoon(EASM)is regarded as a critical dynamic factor in the evolution of precipitation patterns in *** simulation results from the transient climate evolution since the last glacial maximum,this study applies the multivariate empirical orthogonal function(MVEOF)analysis method to investigate the co-evolution relationships of the EASWJ and the EASM during the early,middle,and late Holocene,as well as their influence on precipitation patterns in *** results indicate that all the first MVEOF modes in different time periods of the Holocene display an out-of-phase relationship in the intensity anomaly between the EASWJ and the ***,the jet stream is wider and more tilted in the late *** the influence of secondary circulations formed during their co-evolution,a north-south dipolar precipitation pattern in eastern China(“flood in the south and drought in the north”or“drought in the south and flood in the north”)and an east-west dipolar pattern in northern China(“wet in the west and dry in the east”or“wet in the east and dry in the west”)are found in the early and middle Holocene,while in the late Holocene a regionally-consistent precipitation pattern is witnessed across the whole *** this mode,the precipitation in the middle and late Holocene is primarily dominated by trend *** second MVEOF mode reveals that the EASM weakens when the EASWJ shifts eastward and the jet steam axis shortens during the early Holocene,resulting in a north-south dipolar precipitation pattern in eastern China and a regionally-consistent pattern in northern *** the middle Holocene,dipolar precipitation patterns are also observed in both eastern China and northern China when the EASWJ moves northward and the EASM strengthens,while the moisture condition in North China is less pronounced,and vice *** the late Holocene,the intensity anomali

关键词： Holocene East Asian subtropical westerly jet East Asian summer monsoon Co-evolution Precipitation pattern

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A Novel Class of Energy-Preserving Runge-Kutta Methods for the Korteweg-de Vries Equation

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numerical Mathematics(Theory,Methods and Applications) 2022年第3期15卷 768-792页

作者： Yue Chen Yuezheng Gong Qi Hong Chunwu Wang Department of Mathematics Nanjing University of Aeronautics and AstronauticsNanjing 211106China Key Laboratory of Mathematical Modelling and High Performance Computing of Air Vehicles(NUAA) MIITNanjing 211106China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing 210023China

In this paper,we present a quadratic auxiliary variable approach to develop a new class of energy-preserving Runge-Kutta methods for the Korteweg-de Vries *** quadratic auxiliary variable approach is first proposed to reformulate the original model into an equivalent system,which transforms the energy conservation law of the Korteweg-de Vries equation into two quadratic invariants of the reformulated *** the symplectic Runge-Kutta methods are directly employed for the reformulated model to arrive at a new kind of time semi-discrete schemes for the original *** consistent initial conditions,the proposed methods are rigorously proved to maintain the original energy conservation law of the Korteweg-de Vries *** addition,the Fourier pseudo-spectral method is used for spatial discretization,resulting in fully discrete energy-preserving *** implement the proposed methods effectively,we present a very efficient iterative technique,which not only greatly saves the calculation cost,but also achieves the purpose of practically preserving *** numerical results are addressed to confirm the expected order of accuracy,conservative property and efficiency of the proposed algorithms.

关键词： Quadratic auxiliary variable approach symplectic Runge-Kutta scheme energypreserving algorithm Fourier pseudo-spectral method

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Ru-Ni alloy nanosheets as tandem catalysts for electrochemical reduction of nitrate to ammonia

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Nano Research 2024年第6期17卷 4815-4824页

作者： Xingchao You Jiawei Xu Zechao Zhuang Junkai Xia Suwen Wang Haiyan Wei Yongfu Li Yanjiang Cai Hai Xiang Bing Yu State Key Laboratory of Subtropical Silviculture Zhejiang A&F UniversityHangzhou 311300China Ecological-Environment&Health College(EEHC) Zhejiang A&F UniversityHangzhou 311300China Jiangsu Key Laboratory of Numerical Simulation of Large Scale Complex Systems and School of Chemistry and Materials Science Nanjing Normal UniversityNanjing 210023China Department of Chemistry Tsinghua UniversityBeijing 100084China Department of Chemical Engineering Columbia UniversityNew YorkNY 10027USA

Developing electrocatalysts that exhibit both high activity and ammonia selectivity for nitrate reduction is a significant and demanding challenge,primarily due to the complex nature of the multiple-electron reduction process *** encouraging approach involves coupling highly active precious metals with transition metals to enhance catalytic performance through ***,we report a ruthenium-nickel alloy catalyst with nanosheets(Ru-Ni NSs)structure that achieves a remarkable ammonia Faradaic efficiency of approximately 95.93%,alongside a yield rate of up to 6.11 g·h^(−1)·cm^(−2).Moreover,the prepared Ru-Ni NSs exhibit exceptional stability during continuous nitrate reduction in a flow reactor for 100 h,maintaining a Faradaic efficiency of approximately 90%and an ammonia yield of 37.4 mg·L^(−1)·h^(−1)using 0.05 M nitrate alkaline *** studies reveal that the catalytic process follows a two-step pathway,in which HONO serves as a migration *** presence of a partially oxidized Ru(002)surface enhances the adsorption of nitrate and facilitates the release of the migration intermediate by adjusting the strength of the electrostatic and covalent interactions between the adsorbate and the surface,*** the other hand,the Ni(111)surface promotes the utilization of the migration intermediate and requires less energy for NH_(3)*** tandem process contributes to a high catalytic activity of Ru-Ni NSs towards nitrate reduction.

关键词： alloy catalyst nitrate reduction ammonia synthesis Faradaic efficiency

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The qqsQ(q=u,d;Q=c,b)tetraquark system in a chiral quark model

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Chinese Physics C 2024年第7期48卷 84-105页

作者：杨刚平加伦 Jorge Segovia Department of Physics Zhejiang Normal UniversityJinhua 321004China Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal UniversityNanjing 210023China Departamento de Sistemas Físicos Químicos y NaturalesUniversidad Pablo de OlavideE-41013 SevillaSpain

The S-wave qqsQ(q=u,d;Q=c,b)tetraquarks,with spin-paritiesJ^(P)=0^(+),1^(+),and 2^(+),in both isoscalar and isovector sectors,are systematically studied using a chiral quark *** meson-meson,diquark-antidiquark,and K-type arrangements of quarks and all possible color wave functions are comprehensively *** four-body system is solved using the Gaussian expansion method,a highly efficient computational ***,a complex-scaling formulation of the problem is established to disentangle bound,resonance,and scattering *** theoretical framework has already been successfully applied in various tetra-and penta-quark *** the complete coupled channel and within the complex-range formulation,several narrow resonances of qqsC and qqsb systems are obtained,in each allowed I(J^(P))-channel,within the energy regions of 2.4-3.4 GeV and 5.7-6.7GeV,*** predicted exotic states,which indicate a richer color structure when going towards multiquark systems beyond mesons and baryons,are expected to be confirmed in future high-energy particle and nuclear experiments.

关键词： quantum chromodynamics quark models

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Active and switchable thermal control

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Science China(Physics,Mechanics & Astronomy) 2022年第11期65卷 80-81页

作者： Chenhan Liu Yunfei Chen Micro-and Nano-scale Thermal Measurement and Thermal Management Laboratory School of Energy and Mechanical EngineeringNanjing Normal UniversityNanjing210046China Jiangsu Key Laboratory for Numerical Simulation of Large-Scale Complex Systems Nanjing Normal UniversityNanjing210046China Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments School of Mechanical EngineeringSoutheast UniversityNanjing211100China

In the past century, actively controlling electron transport has led to unprecedented advances in the digital world. Controlling phonon(i.e., thermal) transport like electron transport is a current topic of interest. To realize active and switchable thermal control(Figure 1), numerous studies have been conducted recently due to the emerging challenges in the fields of thermal management, heating and refrigeration.

关键词： thermal transport Figure

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