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K-core attack, equilibrium K-core,and kinetically constrained spin system

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Chinese physics B 2024年第6期33卷 14-26页

作者：周海军 institute of theoretical physics Chinese Academy of SciencesBeijing 100190China MinJiang Collaborative Center for theoretical physics MinJiang UniversityFuzhou 350108China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China

Kinetically constrained spin systems are toy models of supercooled liquids and amorphous solids. In this perspective,we revisit the prototypical Fredrickson–Andersen(FA) kinetically constrained model from the viewpoint of K-core combinatorial optimization. Each kinetic cluster of the FA system, containing all the mutually visitable microscopic occupation configurations, is exactly the solution space of a specific instance of the K-core attack problem. The whole set of different jammed occupation patterns of the FA system is the configuration space of an equilibrium K-core problem. Based on recent theoretical results achieved on the K-core attack and equilibrium K-core problems, we discuss the thermodynamic spin glass phase transitions and the maximum occupation density of the fully unfrozen FA kinetic cluster, and the minimum occupation density and extreme vulnerability of the partially frozen(jammed) kinetic clusters. The equivalence between K-core attack and the fully unfrozen FA kinetic cluster also implies a new way of sampling K-core attack solutions.

关键词： Fredrickson–Andersen model K-core attack spin glass jamming

Supermassive black holes triggered by QCD axion bubbles

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Communications in theoretical physics 2024年第5期76卷 134-139页

作者： hai-jun Li Ying-Quan Peng Wei Chao Yu-Feng zhou Key Laboratory of theoretical physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China Center for Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Fundamental physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China International Centre for theoretical physics Asia-Pacific Beijing/HangzhouChina

Supermassive black holes(SMBHs)are ubiquitous in the center of galaxies,although the origin of their massive seeds is still *** this paper,we investigate the formation of SMBHs from the quantum chromodynamics(QCD)axion *** this case,primordial black holes(PBHs)are considered as the seeds of SMBHs,which are generated from the QCD axion bubbles due to an explicit Peccei–Quinn(PQ)symmetry breaking after *** QCD axion bubbles are formed when the QCD axion starts to oscillate during the QCD phase *** consider a general case in which the axion bubbles are formed with the bubble effective angle θ_(eff)∈(0,π],leading to the minimum PBH mass∼■(10^(4)−10^(7))M⊙for the axion decay constant f_(a)∼■(10^(16))*** PBHs at this mass region may account for the seeds of SMBHs.

关键词： supermassive black holes primordial black holes quantum chromodynamics axion

theoretical insights into efficient oxygen evolution reaction using non-noble metal single-atom catalysts on W2CO2 MXene

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Rare Metals 2024年第10期43卷 5082-5094页

作者： Jing-Yu zhou Zhi-Cheng Han Shu Zhao Tao Yang Da-zhou Yan hai-{3. Yu institute of Advanced Battery Materials and Devices College of Materials Science and EngineeringBeijing University of Technology Key Laboratory of Advanced Functional Materials Ministry of EducationBeijing University of Technology china ENFI Engineering Corporation National Engineering Research Center of Silicon-Based Materials Manufacturing Technology

The pursuit of highly active oxygen evolution reaction （OER） catalysts,especially those free of noble metals,is a focal point in fuel cell *** extensive density functional theory calculations,this study designed and evaluated the activity and stability of singleatom catalysts （SACs） composed of 3.,4d and 5d transition metals supported on tungsten-based MXene for OER *** highlighted the exceptional OER performance of Ni@W2CO2,Rh@W2CO2and Pt@W2CO2,displaying remarkably low overpotentials The catalytic activity of TM@W2CO2SACs exhibited a robust correlation with surface properties,particularly the d-band center index and surface work *** Ni@W2CO2,Rh@W2CO2and Pt@W2CO2emerged as promising candidates for OER and oxygen reduction reaction （ORR） bifunctional catalysis,while Pt@W2CO2and Rh@ W2CO2showed high potential for OER and hydrogen evolution reaction （HER） bifunctional catalysis The effectiveness of tungsten-based MXene as a substrate for non-noble-metal SACs marks a breakthrough in OER catalyst design,driving advancements towards sustainable energy solutions and addressing critical challenges in energy conversion and storage.

关键词： Density functional theory MXene Non-noble metal Oxygen evolution reaction Single-atom catalysts

Cyclic Heating-Annealing and Boltzmann Distribution of Free Energies in a Spin-Glass System

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Communications in theoretical physics 2007年第7期48卷 179-182页

作者： zhou hai-jun institute of theoretical physics,the Chinese Academy of Sciences,beijing 100080,china institute of theoretical physics the Chinese Academy of Sciences Beijing 100080 China

Ergodicity of a spin-glass is broken at low temperatures;the system is trapped in one of many ergodicconfigurational *** between different ergodic domains are achievable through a *** this experiment is repeated infinite times,all ergodic configurational domains will be visited with frequencesthat decreasing exponentially with their free *** mean free energy density of a spin-glass system on a randomgraph is calculated based on this free energy Boltzmann distribution in the present work,by means of the cavity approach.

关键词： spin-glass ergodicity-broken cavity method

Supermassive Primordial Black Holes for Nano-Hertz Gravitational Waves and High-redshift JWST Galaxies

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Research in Astronomy and Astrophysics 2024年第9期24卷 1-6页

作者： hai-Long Huang Yong Cai jun-Qian Jiang jun Zhang Yun-Song Piao School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China institute for Astrophysics School of PhysicsZhengzhou UniversityZhengzhou 450001China International Centre for theoretical physics Asia-Pacific University of Chinese Academy of SciencesBeijing 100190China Taiji Laboratory for Gravitational Wave Universe(beijing/Hangzhou) University of Chinese Academy of SciencesBeijing 100049China School of Fundamental physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China institute of theoretical physics Chinese Academy of SciencesBeijing 100190China

Recently,observational hints for supermassive black holes have been accumulating,prompting the question:Can primordial black holes(PBHs)be supermassive,particularly with masses M■10^(9)M_(⊙)?A supercritical bubble,containing an inflating baby universe,that nucleated during inflation can evolve into a PBH in our observable *** find that when the inflaton slowly transitions past a neighboring vacuum,the nucleation rate of supercritical bubbles inevitably peaks,leading to a mass distribution of multiverse PBHs with a peak mass up to M■10^(11)M_(⊙).Thus,our mechanism naturally provides a primordial origin for supermassive black holes.

关键词： (cosmology:)early universe (cosmology:)inflation (galaxies:)quasars:supermassive black holes

Progress on the antiferromagnetic topological insulator MnBi2Te4

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National Science Review 2024年第2期11卷 33-49页

作者： Shuai Li Tianyu Liu Chang Liu Yayu Wang hai-zhou Lu X.C.Xie Department of physics Harbin Institute of Technology Shenzhen institute for Quantum Science and Engineering and Department of physics Southern University of Science and Technology(SUSTech) Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area(Guangdong) Shenzhen Key Laboratory of Quantum Science and Engineering International Quantum Academy beijing Academy of Quantum Information Sciences beijing Key Laboratory of Optoelectronic Functional Materials&Micro-Nano Devices Department of Physics Renmin University of China State Key Laboratory of Low Dimensional Quantum physics Department of PhysicsTsinghua University Frontier Science Center for Quantum Information Hefei National Laboratory International Center for Quantum Materials School of Physics Peking University institute for Nanoelectronic Devices and Quantum Computing Fudan University

Topological materials, which feature robust surface and/or edge states, have now been a research focus in condensed maTher physics. They represent a new class of materials exhibiting nontrivial topological phases,and provide a platform for exploring exotic transport phenomena, such as the quantum anomalous Hall effect and the quantum spin Hall effect. Recently, magnetic topological materials have attracted considerable interests due to the possibility to study the interplay between topological and magnetic *** particular, the quantum anomalous Hall and axion insulator phases can be realized in topological insulators with magnetic order. MnBi2Te4, as the first intrinsic antiferromagnetic topological insulator discovered, allows the examination of existing theoretical predictions; it has been extensively studied, and many new discoveries have been made. Here we review the progress made on MnBi2Te4from both experimental and theoretical aspects. The bulk crystal and magnetic structures are surveyed first, followed by a review of theoretical calculations and experimental probes on the band structure and surface states, and a discussion of various exotic phases that can be realized in MnBi2Te4. The properties of MnBi2Te4thin films and the corresponding transport studies are then reviewed, with an emphasis on the edge state transport. Possible future research directions in this field are also discussed.

关键词： MnBi2Te4 magnetic topological insulator antiferromagnetic quantum anomalous Hall effect axion insulator

Boost VS_(2) electrochemical reactive kinetics by regulating crystallographic planes and coupling carbon matrix for high performance sodium-ion storage

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Rare Metals 2024年第1期43卷 98-112页

作者： Min Zeng Ming-Shan Wang Lin Chen En-Zhi Li Zhen-Liang Yang Dan zhou hai-Jiao Xie jun-Chen Chen Zhi-Yuan Ma Bing-Shu Guo Bo Yu Xing Li School of New Energy and Materials Southwest Petroleum UniversityChengdu 610500China Energy Storage Research institute Southwest Petroleum UniversityChengdu 610500China institute of Materials China Academy of Engineering PhysicsMianyang 621908China beijing Advanced Innovation Center for Materials Genome Engineering University of Science and TechnologyBeijingBeijing 100083China Hangzhou Yanqu Information Technology Co. Ltd.Hangzhou 310003China

Vanadium disulfide(VS_(2)) as a typical two-dimensional transition metal chalcogenide has excellent competitiveness for sodium-ion storage due to its wide layer spacing(0.575 nm),high theoretical capacity of 93.mAh·g^(-1) originating from multi-electron electrochemical ***,continuous sodiation process accompanied by crystal structural evolution and collapse cause rapid capacity ***,novel few-layer VS_(2)nanosheets with open(001) crystal planes are in-situ constructed on reduced graphene oxide to solve these issues mentioned *** indicates that few-layer VS_(2)provides more Na^(+) storage activity due to the low Na^(+)surface migration energy barrier on exposed crystal(001)*** flexible and high electronic conductivity of carbon matrix also effectively builds multi-level buffer structure and electron transport kinetics to boost the Na^(+)insertion/conversion reactive activity on VS_(2) as well as Na^(+) pseudocapacitance storage kinetics on edges and defects of nano *** coupling effects result in high rate capability and long cycling stability as a battery/capacitor *** delivers conspicuous high energy density of 81 and 40 Wh·kg^(-1) at power density of 118 and 10,286W·kg^(-1),as well as 80% energy retention rate after 5000cycles,confirming its great application potential in sodiumbased storage devices.

关键词： Vanadium disulfide Reduced graphene oxide Anode Sodium-ion battery Sodium-ion capacitor

Fully relativistic energies,transition properties,and lifetimes of lithium-like germanium

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Chinese physics B 2024年第10期33卷 52-61页

作者： Shuang Li Jing zhou Liu-Hong Zhu Xiu-Fei Mei jun Yan School of Electrical and Optoelectronic Engineering West Anhui UniversityLu’an 237012China institute of Applied physics and Computational Mathematics Beijing 100088China Shanghai EBIT Laboratory Institute of Modern PhysicsDepartment of Nuclear Science and TechnologyFudan UniversityShanghai 200433China

Employing two fully relativistic methods,the multi-reference configuration Dirac-Hartree-Fock(MCDHF)methodand the relativistic many-body perturbation theory(RMBPT)method,we report energies and lifetime values for the lowest3. energy levels of the(1s^(2))nl configurations(where the principal quantum number n=2-6 and the angular quantum numberl=0,...,n-1)of lithium-like germanium(Ge XXX),as well as complete data on the transition wavelengths,radiativerates,absorption oscillator strengths,and line strengths between the *** the allowed(E1)and forbidden(magneticdipole M1,magnetic quadrupole M2,and electric quadrupole E2)ones are *** results from the two methodsare consistent with each other and align well with previous accurate experimental and theoretical *** assess theoverall accuracies of present RMBPT results to be likely the most precise ones to *** present fully relativistic resultsshould be helpful for soft x-ray laser research,spectral line identification,plasma modeling and *** datasetspresented in this paper are openly available at https://***/10.57760/sciencedb.j00113.0013..

关键词： multi-reference Dirac-Hartree-Fock relativistic many-body perturbation radiative rate lifetime

Design and prototyping of the readout electronics for the transition radiation detector in the high energy cosmic radiation detection facility

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Nuclear Science and Techniques 2024年第4期35卷 189-199页

作者： Jie-Yu Zhu Yang-zhou Su hai-Bo Yang Fen-Hua Lu Yan Yang Xi-Wen Liu Ping Wei Shu-Cai Wan Hao-Qing Xie Xian-Qin Li Cong Dai Hui-jun Hu Hong-Bang Liu Shu-Wen Tang Cheng-Xin Zhao institute of Modern physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China Guangxi Key Laboratory for Relativistic Astrophysics School of Physical Science and TechnologyGuangxi UniversityNanning 530004China

The high energy cosmic-radiation detection(HERD)facility is planned to launch in 2027 and scheduled to be installed on the china Space *** serves as a dark matter particle detector,a cosmic ray instrument,and an observatory for high-energy gamma rays.A transition radiation detector placed on one of its lateral sides serves dual purpose,(ⅰ)calibrating HERD's electromagnetic calorimeter in the TeV energy range,and(ⅱ)serving as an independent detector for high-energy gamma *** this paper,the prototype readout electronics design of the transition radiation detector is demonstrated,which aims to accurately measure the charge of the anodes using the SAMPA application specific integrated circuit *** electronic performance of the prototype system is evaluated in terms of noise,linearity,and *** the presented design,each electronic channel can achieve a dynamic range of 0–100 fC,the RMS noise level not exceeding 0.15 fC,and the integral nonlinearity was<0.2%.To further verify the readout electronic performance,a joint test with the detector was carried out,and the results show that the prototype system can satisfy the requirements of the detector's scientific goals.

关键词： HERD Dark matter particle detection TRD Readout electronics SAMPA Data acquisition Performance test