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Chinese physics B 2024年第2期33卷 567-576页

作者：邓凯丰李梦胡祥敏陈涛 Institute of Public Safety research Department of Engineering PhysicsTsinghua UniversityBeijing 100084China Anhui Province key laboratory of Human Safety Hefei 230601China Beijing key laboratory of Comprehensive Emergency Response Science Beijing 100084China

An accurate assessment of the evacuation efficiency in case of disasters is of vital importance to the safety design of buildings and street *** sources not only physically but psychologically affect the pedestrians,which may further alter their behavioral *** effect is especially significant in narrow spaces,such as corridors and *** study aims to integrate a non-spreading hazard source into the social force model following the results from a previous experiment and simulation,and to simulate unidirectional pedestrian flows over various crowd densities and clarity–intensity properties of the hazard *** integration include a virtual repulsion force from the hazard source and a decay on the social force *** simulations reveal(i)that the hazard source creates virtual bottlenecks that suppress the flow,(ii)that the inter-pedestrian push forms a stabilisation phase on the flow-density curve within medium-to-high densities,and(iii)that the pedestrians are prone to a less orderly and stable pattern of movement in low clarity–intensity scenarios,possibly with lateral collisions passing the hazard source.

关键词： evacuation social force model hazard source unidirectional pedestrian flow

Spin logic devices based on negative differential resistance -enhanced anomalous Hall effect

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1437-1448页

作者： Hongming Mou Ziyao Lu Yuchen Pu Zhaochu Luo Xiaozhong Zhang key laboratory of Advanced Materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China State key laboratory of Artificial Microstructure and Mesoscopic physics School of PhysicsPeking UniversityBeijing 100871China

Owing to rapid developments in spintronics,spin-based logic devices have emerged as promising tools for next-generation computing *** paper provides a comprehensive review of recent advancements in spin logic devices,particularly focusing on fundamental device concepts rooted in nanomagnets,magnetoresistive random access memory,spin–orbit torques,electric-field modu-lation,and magnetic domain *** operation principles of these devices are comprehensively analyzed,and recent progress in spin logic devices based on negative differential resistance-enhanced anomalous Hall effect is *** devices exhibit reconfigur-able logic capabilities and integrate nonvolatile data storage and computing *** current-driven spin logic devices,negative differential resistance elements are employed to nonlinearly enhance anomalous Hall effect signals from magnetic bits,enabling reconfig-urable Boolean logic ***,voltage-driven spin logic devices employ another type of negative differential resistance ele-ment to achieve logic functionalities with excellent cascading *** cascading several elementary logic gates,the logic circuit of a full adder can be obtained,and the potential of voltage-driven spin logic devices for implementing complex logic functions can be *** review contributes to the understanding of the evolving landscape of spin logic devices and underscores the promising pro-spects they offer for the future of emerging computing schemes.

关键词： spin logic spin–orbit torque negative differential resistance full-adder

Applying deep learning technique to chiral magnetic wave search

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Chinese physics C 2024年第8期48卷 170-176页

作者： Yuan-Sheng Zhao Xu-Guang Huang physics Department and Center for Particle physics and Field Theory Fudan UniversityShanghai 200433China key laboratory of Nuclear physics and Ion-beam Application(MOE) Fudan UniversityShanghai 200433China Shanghai research Center for Theoretical Nuclear physics National Natural Science Foundation of China and Fudan UniversityShanghai 200438China

The chiral magnetic wave(CMW)is a collective mode in quark-gluon plasma originated from the chiral magnetic effect(CME)and chiral separation *** detection in heavy-ion collisions is challenging owing to significant background ***[*** et al.,***.C 106,L051901(2022)],we constructed a neural network that accurately identifies the CME-related signal from the final-state pion *** this study,we have generalized this neural network to the case of CMW *** show that,after an updated training,the neural network effectively recognizes the CMW-related ***,we have assessed the performance of the neural network in comparison with other known methods for CMW search.

关键词： deep learning chiral magnetic wave relativistic heavy-ion collisions

Linear instability of hairy black holes in Horndeski theory

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Chinese physics C 2024年第7期48卷 253-258页

作者：张超朱涛 Beijing key laboratory of Optical Detection Technology for Oil and Gas Basic Research Center for Energy InterdisciplinaryCollege of ScienceChina University of Petroleum-BeijingBeijing 102249China Institute for Theoretical physics and Cosmology Zhejiang University of TechnologyHangzhou 310023China United Center for Gravitational wave physics(UCGWP) Zhejiang University of TechnologyHangzhou 310023China

Horndeski theory constitutes the most general model of scalar-tensor *** has attracted much attention in recent years in relation with black holes,celestial dynamics,stability analysis,*** is important to note that,for certain subclasses of Horndeski models,one can obtain analytic solutions for the background *** facilitates the investigation of the corresponding stability problems in *** particular,we aim to determine the constraints to the model or theory under which the stability conditions can be *** this study,we focused on a subclass of Horndeski theory and a set of analytic background *** addition,the odd-parity gravitational perturbation and 2nd-order Lagrangian were *** careful analysis,the instability was identified within the neighborhood of the event *** allows exclusion of a specific geometry for the *** an instability is implanted in the structure of the corresponding Lagrangian and is not erased by simply adding numerical constraints on the coupling *** a starting point of our research,the current study provides insights for further exploration of the Horndeski theory.

关键词： black holes black hole perturbations scalar-tensor theories Horndeski theory

Simulation of optimal work extraction for quantum systems with work storage

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Chinese physics B 2024年第2期33卷 195-203页

作者：宋鹏飞张旦波 key laboratory of Atomic and Subatomic Structure and Quantum Control(Ministry of Education) and School of PhysicsSouth China Normal UniversityGuangzhou 510006China Guangdong Provincial key laboratory of Quantum Engineering and Quantum Materials Guangdong–Hong Kong Joint Laboratory of Quantum Matterand Frontier Research Institute for PhysicsSouth China Normal UniversityGuangzhou 510006China

The capacity to extract work from a quantum heat machine is not only of practical value but also lies at the heart of understanding quantum *** this paper,we investigate optimal work extraction for quantum systems with work storage,where extracting work is completed by a unitary evolution on the composite *** consider the physical requirement of energy conservation both strictly and on *** both,we construct their corresponding unitaries and propose variational quantum algorithms for optimal work *** show that maximal work extraction in general can be feasible when energy conservation is satisfied on *** demonstrate with numeral simulations using a continuous-variable work *** work show an implementation of a variational quantum computing approach for simulating work extraction in quantum systems.

关键词： quantum algorithm quantum thermodyanmics

Nondestructive Nonlinear Optical Microscopy Revealed the Blackening Mechanism of Ancient Chinese Jades

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research 2024年第3期2023卷 391-399页

作者： Yaxin Chen Rong Wang Minbiao Ji State key laboratory of Surface physics and Department of physics Human Phenome InstituteAcademy for Engineering and TechnologyKey Laboratory of Micro and Nano Photonic Structures(Ministry of Education)Yiwu Research Institute of Fudan UniversityFudan UniversityShanghai 200433China Department of Cultural Heritage and Museology Fudan UniversityShanghaiChina

Jade is most valued in Chinese culture since ancient times. For unearthed jade artifacts, the alteration color resulting from weathering effects and human activities provides information for cultural heritage conservation, archaeology, and history. Currently, the noninvasive 3-dimensional characterization of jade artifacts with high chemical and spatial resolution remains challenging. In this work, we applied femtosecond pump–probe microscopy and second harmonic generation microscopy techniques to study the black alteration of an ancient jade artifact of the late Spring and Autumn period (546 to 476 BC). The direct cause of the “mercury alteration” phenomena was discovered to be the conversion of metacinnabar from buried cinnabar in the tomb. Furthermore, a 3-dimensional optical reconstruction of the black alteration was achieved, providing a high-resolution method for analyzing the blackening mechanism without the need of sample damage. Our approach opens up new opportunities to extract microscopic spatiochemical information for a broad range of alteration colors in jade artifacts.

关键词： pump Nonlinear buried

Layer-Valley Hall Effect under Inversion and Time-Reversal Symmetries

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Chinese physics Letters 2024年第6期41卷 88-97页

作者：赵交交刘贵斌陈鹏姚裕贵张广宇杜罗军 Beijing national laboratory for Condensed Matter physics and Key Laboratory for Nanoscale Physics and DevicesInstitute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Centre for Quantum physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement(MOE)School of PhysicsBeijing Institute of TechnologyBeijing 100081China Beijing key Lab of Nanophotonics&Ultrafine Optoelectronic Systems School of PhysicsBeijing Institute of TechnologyBeijing 100081China Schoolof Microelectronics Southern University of Science and TechnologyShenzhen 518055China Songshan Lake Materials laboratory Dongguan 523808China

Hall effects have been the central paradigms in modern physics,materials science and practical applications,and have led to many exciting breakthroughs,including the discovery of topological Chern invariants and the revolution of metrological resistance *** date,the Hall effects have mainly focused on a single degree of freedom(Do F),and most of them require the breaking of spatial-inversion and/or time-reversal *** we demonstrate a new type of Hall effect,i.e.,layer-valley Hall effect,based on a combined layer-valley Do F characterized by the product of layer and valley *** layer-valley Hall effect has a quantum origin arising from the layer-valley contrasting Berry curvature,and can occur in nonmagnetic centrosymmetric crystals with both spatial-inversion and time-reversal symmetries,transcending the symmetry constraints of single Do F Hall effect based on the constituent layer or valley ***,the layer-valley Hall effect is highly tunable and shows a W-shaped pattern in response to the out-of-plane electric ***,we discuss the potential detection approaches and material-specific design principles of layer-valley Hall *** results demonstrate novel Hall physics and open up exotic paradigms for new research direction of layer-valleytronics that exploits the quantum nature of the coupled layer-valley DoF.

关键词： quantum Inversion curvature

Measurement of 2p-3d absorption in a hot molybdenum plasma

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Matter and Radiation at Extremes 2024年第4期9卷 68-79页

作者： Gang Xiong Bo Qing Zhiyu Zhang Longfei Jing Yang Zhao Minxi Wei Yimeng Yang Lifei Hou Chengwu Huang Tuo Zhu Tianming Song Min Lv Yan Zhao Yuxue Zhang Guohong Yang Zeqing Wu Jun Yan Yaming Zou Jiyan Zhang Jiamin Yang Shanghai EBIT laboratory and Key Laboratory of Nuclear Physics and Ion-Beam Application(MOE)Institute of ModernPhysicsFudan UniversityShanghai 200433China Laser Fusion research Center China Academy of Engineering PhysicsMianyang 621900China Institute of Applied physics and Computational Mathematics Beijing 100088China

We present measurements of the 2p-3d transition opacity of a hot molybdenum-scandium sample with nearly half-vacant molybdenum M-shell configurations.A plastic-tamped molybdenum-scandium foil sample is radiatively heated to high temperature in a compact D-shaped gold Hohlraum driven by∼30 kJ laser energy at the SG-100 kJ laser facility.X rays transmitted through the molybdenum and scandium plasmas are diffracted by crystals and finally recorded by image *** electron temperatures in the sample in particular spatial and temporal zones are determined by the K-shell absorption of the scandium plasma.A combination of the IRAD3D view factor code and the MULTI hydrodynamic code is used to simulate the spatial distribution and temporal behavior of the sample temperature and *** inferred temperature in the molybdenum plasma reaches a average of 138±11 eV.A detailed configuration-accounting calculation of the n=2–3 transition absorption of the molybdenum plasma is compared with experimental measurements and quite good agreement is *** present measurements provide an opportunity to test opacity models for complicated M-shell configurations.

关键词： molybdenum absorption configuration

High-performance terahertz modulators induced by substrate field in Te-based all-2D heterojunctions

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Light(Science & Applications) 2024年第3期13卷 577-586页

作者： Pujing Zhang Qihang Liang Qingli Zhou Jinyu Chen Menglei Li Yuwang Deng Wanlin Liang Liangliang Zhang Qinghua Zhang Lin Gu Chen Ge Kui-juan Jin Cunlin Zhang Guozhen Yang Department of physics Key Laboratory of Terahertz OptoelectronicsMinistry of Educationand Beijing Advanced Innovation Center for Imaging Theory and TechnologyCapital Normal UniversityBeijing 100048China Beijing national laboratory for Condensed Matter physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Department of Materials Science and Engineering Beijing National Center for Electron Microscopy and Laboratory of Advanced MaterialsTsinghua UniversityBeijing 100084China

High-performance active terahertz modulators as the indispensable core components are of great importance for the next generation communication ***,they currently suffer from the tradeoff between modulation depth and ***,we introduce two-dimensional(2D)tellurium(Te)nanofilms with the unique structure as a new class of optically controlled terahertz modulators and demonstrate their integrated heterojunctions can successfully improve the device performances to the optimal and applicable levels among the existing all-2D broadband *** photoresponse measurements confirm the significant impact of the stacking *** first clarify the direction of the substrate-induced electric field through first-principles calculations and uncover the unusual interaction mechanism in the photoexcited carrier dynamics associated with the charge transfer and interlayer exciton *** advances the fundamental and applicative research of Te nanomaterials in high-performance terahertz optoelectronics.

关键词： performance field terahertz

Quantized anomalous Hall resistivity achieved in molecular beam epitaxy-grown Mn Bi2Te4 thin films

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national Science Review 2024年第2期11卷 24-32页

作者： Yunhe Bai Yuanzhao Li Jianli Luan Ruixuan Liu Wenyu Song Yang Chen Peng-Fei Ji Qinghua Zhang Fanqi Meng Bingbing Tong Lin Li Yuying Jiang Zongwei Gao Lin Gu Jinsong Zhang Yayu Wang Qi-Kun Xue Ke He Yang Feng Xiao Feng State key laboratory of Low Dimensional Quantum physics Department of Physics Tsinghua University Institute of physics Chinese Academy of Sciences School of Materials Science and Engineering Tsinghua University Beijing Academy of Quantum Information Sciences Frontier Science Center for Quantum Information Hefei national laboratory Southern University of Science and Technology

The intrinsic magnetic topological insulator MnBi2Te4provides a feasible pathway to the high-temperature quantum anomalous Hall（QAH） effect as well as various novel topological quantum phases. Although quantized transport properties have been observed in exfoliated MnBi2Te4thin flakes, it remains a big challenge to achieve molecular beam epitaxy（MBE）-grown MnBi2Te4thin films even close to the quantized regime. In this work, we report the realization of quantized anomalous Hall resistivity in MBE-grown MnBi2Te4thin films with the chemical potential tuned by both controlled in situ oxygen exposure and top gating. We find that elongated post-annealing obviously elevates the temperature to achieve quantization of the Hall resistivity, but also increases the residual longitudinal resistivity, indicating a picture of high-quality QAH puddles weakly coupled by tunnel barriers. These results help to clarify the puzzles in previous experimental studies on MnBi2Te4and to find a way out of the big difficulty in obtaining MnBi2Te4samples showing quantized transport properties.

关键词： intrinsic magnetic topological insulator quantized anomalous Hall resistivity molecular beam epitaxy quantized transport property