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Topological magnons driven by the Dzyaloshinskii-Moriya interaction in the centrosymmetric ferromagnet Mn5Ge3

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arXiv 2022年

作者： dos Santos Dias, M. Biniskos, N. dos Santos, F.J. Schmalzl, K. Persson, J. Bourdarot, F. Marzari, N. Blügel, S. Brückel, T. Lounis, S. Peter Grünberg Institut Institute for Advanced Simulation Forschungszentrum Jülich & JARA JülichD-52425 Germany Faculty of Physics University of Duisburg-Essen and CENIDE DuisburgD-47053 Germany Scientific Computing Department STFC Daresbury Laboratory WarringtonWA4 4AD United Kingdom Forschungszentrum Jülich GmbH Jülich Centre for Neutron Science at MLZ Lichtenbergstr. 1 GarchingD-85748 Germany Laboratory for Materials Simulations Paul Scherrer Institut Villigen PSI5232 Switzerland École Polytechnique Fédérale de Lausanne Lausanne1015 Switzerland Forschungszentrum Jülich GmbH Jülich Centre for Neutron Science at ILL 71 Avenue des Martyrs GrenobleF-38000 France JARA-FIT JülichD-52425 Germany Université Grenoble Alpes CEA IRIG MEM MDN GrenobleF-38000 France

The phase of the quantum-mechanical wave function can encode a topological structure with wide-ranging physical consequences, such as anomalous transport effects and the existence of edge states robust against perturbations. While this has been exhaustively demonstrated for electrons, properties associated with the elementary quasiparticles in magnetic materials are still underexplored. Here, we show theoretically and via inelastic neutron scattering experiments that the bulk ferromagnet Mn5Ge3 hosts gapped topological Dirac magnons. Although inversion symmetry prohibits a net Dzyaloshinskii-Moriya interaction in the unit cell, it is locally allowed and is responsible for the gap opening in the magnon spectrum. This gap is predicted and experimentally verified to close by rotating the magnetization away from the c-axis with an applied magnetic field. Hence, Mn5Ge3 realizes a gapped Dirac magnon material in three dimensions. Its tunability by chemical doping or by thin film nanostructuring defines an exciting new platform to explore and design topological magnons. More generally, our experimental route to verify and control the topological character of the magnons is applicable to bulk centrosymmetric hexagonal materials, which calls for systematic investigation. © 2022, CC BY.

关键词： Germanium alloys

Constraints on the two-dimensional pseudospin-12 Mott insulator description of Sr2IrO4

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Physical Review B 2022年第24期105卷 245130-245130页

作者： B. Zwartsenberg R. P. Day E. Razzoli M. Michiardi M. X. Na G. Zhang J. D. Denlinger I. Vobornik C. Bigi B. J. Kim I. S. Elfimov E. Pavarini A. Damascelli Quantum Matter Institute University of British Columbia Vancouver Canada BC V6T 1Z4 Department of Physics and Astronomy University of British Columbia Vancouver Canada BC V6T 1Z1 Max Planck Institute for Chemical Physics of Solids Nöthnitzer Straße 40 01187 Dresden Germany Key Laboratory of Materials Physics Institute of Solid State Physics HFIPS Chinese Academy of Sciences Hefei 230031 People's Republic of China Advanced Light Source Lawrence Berkeley National Laboratory Berkeley California 94720 USA Istituto Officina dei Materiali (IOM)-CNR Laboratorio TASC in Area Science Park S.S.14 Km 163.5 I-34149 Trieste Italy Dipartimento di Fisica Universit di Milano Via Celoria 16 I-20133 Milano Italy Department of Physics Pohang University of Science and Technology Pohang 790-784 South Korea Center for Artificial Low Dimensional Electronic Systems Institute for Basic Science (IBS) 77 Cheongam-Ro Pohang 790-784 Republic of Korea Max Planck Institute for Solid State Research Heisenbergstraße 1 D-70569 Stuttgart Germany Institute for Advanced Simulation Forschungszentrum Jülich D-52425 Jülich Germany JARA High-Performance Computing Forschungszentrum Jülich D-52425 Jülich Germany

Sr2IrO4 has often been described via a simple, one-band pseudospin-12 model subject to electron-electron interactions on a square lattice, fostering analogies with cuprate superconductors believed to be well described by a similar model. In this work we argue—based on a detailed study of the low-energy electronic structure by circularly polarized spin and angle-resolved photoemission spectroscopy combined with dynamical mean-field theory calculations—that a pseudospin-12 model fails to capture the full complexity of the system. We show instead that a realistic multiband Hubbard Hamiltonian, accounting for the full correlated t2g manifold, provides a detailed description of the interplay between spin-orbital entanglement and electron-electron interactions and yields quantitative agreement with experiments. Our analysis establishes that the j3/2 states make up a substantial percentage of the low-energy spectral weight, i.e., approximately 74% as determined from the integration of the j-resolved spectral function in the 0 to −1.64eV energy range. The results in our work are of relevance not only to Ir-based materials but also more generally to multiorbital materials with closely spaced energy scales.

关键词： Spin-orbit coupling High-temperature superconductors Mott insulators Angle-resolved photoemission spectroscopy Dynamical mean field theory Hubbard model Spin-resolved photoemission spectroscopy

DeePMD-kit v3: A Multiple-Backend Framework for Machine Learning Potentials

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arXiv 2025年

作者： Zeng, Jinzhe Zhang, Duo Peng, Anyang Zhang, Xiangyu He, Sensen Wang, Yan Liu, Xinzijian Bi, Hangrui Li, Yifan Cai, Chun Zhang, Chengqian Du, Yiming Zhu, Jia-Xin Mo, Pinghui Huang, Zhengtao Zeng, Qiyu Shi, Shaochen Qin, Xuejian Yu, Zhaoxi Luo, Chenxing Ding, Ye Liu, Yun-Pei Shi, Ruosong Wang, Zhenyu Bore, Sigbjørn Løland Chang, Junhan Deng, Zhe Ding, Zhaohan Han, Siyuan Jiang, Wanrun Ke, Guolin Liu, Zhaoqing Lu, Denghui Muraoka, Koki Oliaei, Hananeh Singh, Anurag Kumar Que, Haohui Xu, Weihong Xu, Zhangmancang Zhuang, Yong-Bin Dai, Jiayu Giese, Timothy J. Jia, Weile Xu, Ben York, Darrin M. Zhang, Linfeng Wang, Han School of Artificial Intelligence and Data Science Unversity of Science and Technology of China Hefei China AI for Science Institute Beijing100080 China DP Technology Beijing100080 China Academy for Advanced Interdisciplinary Studies Peking University Beijing100871 China State Key Lab of Processors Institute of Computing Technology Chinese Academy of Sciences Beijing100871 China University of Chinese Academy of Sciences Beijing China Baidu Inc. Beijing China Department of Computer Science University of Toronto TorontoON Canada Department of Chemistry Princeton University PrincetonNJ08540 United States University of Chinese Academy of Sciences Beijing100871 China State Key Laboratory of Physical Chemistry of Solid Surfaces iChEM College of Chemistry and Chemical Engineering Xiamen University Xiamen361005 China College of Integrated Circuits Hunan University Changsha410082 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Center for Smart Materials and Device Integration School of Material Science and Engineering Wuhan University of Technology Wuhan430070 China College of Science National University of Defense Technology Changsha410073 China Hunan Key Laboratory of Extreme Matter and Applications National University of Defense Technology Changsha410073 China ByteDance Research Beijing100098 China Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo315201 China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of Sciences Beijing100049 China Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education College of Chemistry Beijing Normal University Beijing100875 China Department of Geosciences Princeton University PrincetonNJ08544 United States Department of Applied Physics and Applied Mathematics Columbia University New YorkNY10027 United States IKKEM Fujian Xiamen361005 China Graduate

In recent years, machine learning potentials (MLPs) have become indispensable tools in physics, chemistry, and materials science, driving the development of software packages for molecular dynamics (MD) simulations and related applications. These packages, typically built on specific machine learning frameworks such as TensorFlow, PyTorch, or JAX, face integration challenges when advanced applications demand communication across different frameworks. The previous TensorFlow-based implementation of DeePMD-kit exemplified these limitations. In this work, we introduce DeePMD-kit version 3, a significant update featuring a multi-backend framework that supports TensorFlow, PyTorch, JAX, and PaddlePaddle backends, and demonstrate the versatility of this architecture through the integration of other MLPs packages and of Differentiable Molecular Force Field. This architecture allows seamless backend switching with minimal modifications, enabling users and developers to integrate DeePMD-kit with other packages using different machine learning frameworks. This innovation facilitates the development of more complex and interoperable workflows, paving the way for broader applications of MLPs in scientific research. Copyright © 2025, The Authors. All rights reserved.

关键词： Molecular dynamics

Coupled-channel approach to Tcc+ including three-body effects

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Physical Review D 2022年第1期105卷 014024-014024页

作者： Meng-Lin Du Vadim Baru Xiang-Kun Dong Arseniy Filin Feng-Kun Guo Christoph Hanhart Alexey Nefediev Juan Nieves Qian Wang Instituto de Física Corpuscular (centro mixto CSIC-UV) Institutos de Investigación de Paterna Apartado 22085 46071 Valencia Spain Institut für Theoretische Physik II Ruhr-Universität Bochum D-44780 Bochum Germany Institute for Theoretical and Experimental Physics NRC “Kurchatov Institute” Moscow 117218 Russia CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100190 China School of Physical Sciences University of Chinese Academy of Sciences Beijing 100049 China Institute for Advanced Simulation Institut für Kernphysik and Jülich Center for Hadron Physics Forschungszentrum Jülich D-52425 Jülich Germany P.N. Lebedev Physical Institute of the Russian Academy of Sciences 119991 Leninskiy Prospect 53 Moscow Russia Moscow Institute of Physics and Technology 141700 Institutsky lane 9 Dolgoprudny Moscow Region Russia Guangdong Provincial Key Laboratory of Nuclear Science Institute of Quantum Matter South China Normal University Guangzhou 510006 China Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Guangdong-Hong Kong Joint Laboratory of Quantum Matter Southern Nuclear Science Computing Center South China Normal University Guangzhou 510006 China

A coupled-channel approach is applied to the charged tetraquark state Tcc+ recently discovered by the LHCb Collaboration. The parameters of the interaction are fixed by a fit to the observed line shape in the three-body D0D0π+ channel. Special attention is paid to the three-body dynamics in the Tcc+ due to the finite life time of the D*. An approach to the Tcc+ is argued to be self-consistent only if both manifestations of the three-body dynamics, the pion exchange between the D and D* mesons and the finite D* width, are taken into account simultaneously to ensure that three-body unitarity is preserved. This is especially important to precisely extract the pole position in the complex energy plane whose imaginary part is very sensitive to the details of the coupled-channel scheme employed. The D0D0 and D0D+ invariant mass distributions, predicted based on this analysis, are in good agreement with the LHCb data. The low-energy expansion of the D*D scattering amplitude is performed and the low-energy constants (the scattering length and effective range) are extracted. The compositeness parameter of the Tcc+ is found to be close to unity, which implies that the Tcc+ is a hadronic molecule generated by the interactions in the D*+D0 and D*0D+ channels. Employing heavy-quark spin symmetry, an isoscalar D*D* molecular partner of the Tcc+ with JP=1+ is predicted under the assumption that the DD*−D*D* coupled-channel effects can be neglected.

关键词： Hadron-hadron interactions Particle interactions

Same influenza, different responses: Social media can sense a regional spectrum of symptoms

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arXiv 2019年

作者： Shan, Siqing Jia, Yingwei Zhaoa, Jichang School of Economics and Management Beihang University Beijing China Beijing Key Laboratory of Emergency Support Simulation Technologies for City Operation Beijing China Beijing Advanced Innovation Center for Big Data and Brain Computing Beijing China

Influenza is an acute respiratory infection caused by a virus. It is highly contagious and rapidly mutative. However, its epidemiological characteristics are conventionally collected in terms of outpatient records. In fact, the subjective bias of the doctor emphasizes exterior signs, and the necessity of face-to-face inquiry results in an inaccurate and time-consuming manner of data collection and aggregation. Accordingly, the inferred spectrum of syndromes can be incomplete and lagged. With a massive number of users being sensors, online social media can indeed provide an alternative approach. Voluntary reports in Twitter and its variants can deliver not only exterior signs but also interior feelings such as emotions. These sophisticated signals can further be efficiently collected and aggregated in a real-time manner, and a comprehensive spectrum of syndromes could thus be inferred. Taking Weibo as an example, it is confirmed that a regional spectrum of symptoms can be credibly sensed. Aside from the differences in symptoms and treatment incentives between northern and southern China, it is also surprising that patients in the south are more optimistic, while those in the north demonstrate more intense emotions. The differences sensed from Weibo can even help improve the performance of regressions in monitoring influenza. Our results suggest that self-reports from Copyright © 2019, The Authors. All rights reserved.

关键词： Social networking (online)

Constraints on the two-dimensional pseudo-spin 1/2 Mott insulator description of Sr2IrO4

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arXiv 2022年

作者： Zwartsenberg, Berend Day, Ryan P. Razzoli, Elia Michiardi, Matteo Na, Meng Xing Zhang, Guoren Denlinger, Jonathan D. Vobornik, Ivana Bigi, Chiara Kim, Bum Joon Elfimov, Ilya S. Pavarini, Eva Damascelli, Andrea Quantum Matter Institute University of British Columbia VancouverBCV6T 1Z4 Canada Department of Physics and Astronomy University of British Columbia VancouverBCV6T 1Z1 Canada Max Planck Institute for Chemical Physics of Solids Nöthnitzer Straße 40 Dresden01187 Germany Key Laboratory of Materials Physics Institute of Solid State Physics Hfips Chinese Academy of Sciences Hefei230031 China Advanced Light Source Lawrence Berkeley National Laboratory BerkeleyCA94720 United States -CNR Laboratorio Tasc Area Science Park S.S.14 Km 163.5 TriesteI-34149 Italy Dipartimento di Fisica Universitá di Milano Via Celoria 16 MilanoI-20133 Italy Department of Physics Pohang University of Science and Technology Pohang790-784 Korea Republic of 77 Cheongam-Ro Pohang790-784 Korea Republic of Max Planck Institute for Solid State Research Heisenbergstraße 1 StuttgartD-70569 Germany Institute for Advanced Simulation Forschungszentrum Jülich JülichD-52425 Germany Jara High-Performance Computing Forschungszentrum Jülich Jülich Germany

Sr2IrO4has often been described via a simple, one-band pseudo-spin 1/2 model, subject to electron-electron interactions, on a square lattice, fostering analogies with cuprate superconductors, believed to be well described by a similar model. In this work we argue - based on a detailed study of the low-energy electronic structure by circularly polarized spin and angle-resolved photoemission spectroscopy combined with dynamical mean-field theory calculations - that a pseudo-spin 1/2 model fails to capture the full complexity of the system. We show instead that a realistic multi-band Hubbard Hamiltonian, accounting for the full correlated t2gmanifold, provides a detailed description of the interplay between spin-orbital entanglement and electron-electron interactions, and yields quantitative agreement with experiments. Our analysis establishes that the j3/2states make up a substantial percentage of the low energy spectral weight, i.e. approximately 74% as determined from the integration of the j-resolved spectral function in the 0 to -1.64 eV energy range. The results in our work are not only of relevance to iridium based materials, but more generally to the study of multi-orbital materials with closely spaced energy scales. © 2022, CC BY-NC-ND.

关键词： Electron-electron interactions

Enhanced luminescence performance of NIR phosphor via energy transfer for NIR pc-LEDs

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Enhanced luminescence performance of NIR phosphor via energy...

第九届国际稀土开发与应用研讨会暨2019中国稀土学会学术年会

作者： Tongyu Gao Weidong Zhuang Ronghui Liu Yuanhong Liu Chunpei Yan Junhang Tian Guantong Chen Xiaoxia Chen Yaling Zheng Ligen Wang National Engineering Research Center for Rare Earth Materials General Research Institute for Nonferrous Metalsand Grirem Advanced Materials Co.Ltd. Center for Computing and Simulation of Advanced Materials and State Key Laboratory of Nonferrous Metals and Processes General Research Institute for Nonferrous Metals

Super broadband near-infrared(NIR) phosphor is demanded for food testing, the technique works by sending a broad NIR emission on food stuffs that contains compounds such as sugar with characteristic wide NIR absorption. Unfortunately, the phosphor still suffers from low efficient in practical applications. Herein,the luminescence performance of a super broadband NIR phosphor has been enhanced via energy transfer. It is of great importance that the PLE spectra of the phosphor strongly overlap with the emission of commercial blue LED chips, verifying its potential in the application of blue-pumped LEDs. The preferential crystallographic site of emission center is demonstrated on the basis of EPR spectrum, Rietveld refinement and the first-principles DFT calculations. Furthermore, the optimized phosphor is employed for fabricating a blue based NIR phosphor-converted LEDs(NIR pc-LEDs), the forward voltage and the intensity of LED hardly change after thermal aging for 500 hours under high temperature/high humidity condition,indicating its great reliability for NIR pc-LEDs. These results indicate the phosphor to be a promising candidate for NIR pc-LEDs in view of its capability for blue to enhanced broadband NIR conversion.

关键词： NIR phosphor Energy Transfer

swTVM: Towards Optimized Tensor Code Generation for Deep Learning on Sunway Many-Core Processor

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arXiv 2019年

作者： Li, Mingzhen Liu, Changxi Liao, Jianjin Zheng, Xuegui Yang, Hailong Sun, Rujun Xu, Jun Gan, Lin Yang, Guangwen Luan, Zhongzhi Qian, Depei School of Computer Science and Engineering Beihang University Beijing China State Key Laboratory of Software Development Environment Beijing China National University of Singapore Singapore Singapore State Key Laboratory of Mathematical Engineering and Advanced Computing Wuxi China Science and Technology on Special System Simulation Laboratory Beijing Simulation Center Beijing China Department of Computer Science and Technology Tsinghua University Beijing China

The flourish of deep learning frameworks and hardware platforms has been demanding an efficient compiler that can shield the diversity in both software and hardware in order to provide application portability. Among the existing deep learning compilers, TVM is well known for its efficiency in code generation and optimization across diverse hardware devices. In the meanwhile, the Sunway many-core processor renders itself as a competitive candidate for its attractive computational power in both scientific computing and deep learning workloads. This paper combines the trends in these two directions. Specifically, we propose swTVM that extends the original TVM to support ahead-of-time compilation for architecture requiring cross-compilation such as Sunway. In addition, we leverage the architecture features during the compilation such as core group for massive parallelism, DMA for high bandwidth memory transfer and local device memory for data locality, in order to generate efficient codes for deep learning workloads on Sunway. The experiment results show that the codes generated by swTVM achieves 1.79× on average compared to the state-of-the-art deep learning framework on Sunway, across six representative benchmarks. This work is the first attempt from the compiler perspective to bridge the gap of deep learning and Sunway processor particularly with productivity and efficiency in mind. We believe this work will encourage more people to embrace the power of deep learning and Sunway many-core processor. Copyright © 2019, The Authors. All rights reserved.

关键词： Program compilers

Quantum simulation for High-Energy Physics

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PRX Quantum 2023年第2期4卷 027001-027001页

作者： Christian W. Bauer Zohreh Davoudi A. Baha Balantekin Tanmoy Bhattacharya Marcela Carena Wibe A. de Jong Patrick Draper Aida El-Khadra Nate Gemelke Masanori Hanada Dmitri Kharzeev Henry Lamm Ying-Ying Li Junyu Liu Mikhail Lukin Yannick Meurice Christopher Monroe Benjamin Nachman Guido Pagano John Preskill Enrico Rinaldi Alessandro Roggero David I. Santiago Martin J. Savage Irfan Siddiqi George Siopsis David Van Zanten Nathan Wiebe Yukari Yamauchi Kübra Yeter-Aydeniz Silvia Zorzetti Physics Division Lawrence Berkeley National Laboratory Berkeley California 94720 USA Department of Physics Maryland Center for Fundamental Physics and the NSF Institute for Robust Quantum Simulation University of Maryland College Park Maryland 20742 USA Department of Physics University of Wisconsin Madison Wisconsin 53706 USA T-2 Los Alamos National Laboratory Los Alamos New Mexico 87545 USA Fermi National Accelerator Laboratory Batavia Illinois 60510 USA Enrico Fermi Institute University of Chicago Chicago Illinois 60637 USA Kavli Institute for Cosmological Physics University of Chicago Chicago Illinois 60637 USA Department of Physics University of Chicago Chicago Illinois 60637 USA Department of Physics and Illinois Center for the Advanced Study of the Universe and Illinois Quantum Information Science and Technology Center University of Illinois Urbana Illinois 61801 USA QuEra Computing Inc Boston Massachusetts 02135 USA Department of Mathematics University of Surrey Guildford Surrey GU2 7XH United Kingdom Center for Nuclear Theory Department of Physics and Astronomy Stony Brook University New York 11794-3800 USA Department of Physics Brookhaven National Laboratory Upton New York 11973 USA Peng Huanwu Center for Fundamental Theory Hefei Anhui 230026 China Interdisciplinary Center for Theoretical Study University of Science and Technology of China Hefei Anhui 230026 China Pritzker School of Molecular Engineering Chicago Quantum Exchange and Kadanoff Center for Theoretical Physics University of Chicago Illinois 60637 USA qBraid Co. Harper Court 5235 Chicago Illinois 60615 USA Department of Physics Harvard University Cambridge Massachusetts 02138 USA Department of Physics and Astronomy University of Iowa Iowa City Iowa 52242 USA Duke Quantum Center Duke University Durham North Carolina 27701 USA Department of Electrical and Computer Engineering Duke University Durham North Carolina 27708 USA Department of Physics Duke University

It is for the first time that quantum simulation for high-energy physics (HEP) is studied in the U.S. decadal particle-physics community planning, and in fact until recently, this was not considered a mainstream topic in the community. This fact speaks of a remarkable rate of growth of this subfield over the past few years, stimulated by the impressive advancements in quantum information sciences (QIS) and associated technologies over the past decade, and the significant investment in this area by the government and private sectors in the U.S. and other countries. High-energy physicists have quickly identified problems of importance to our understanding of nature at the most fundamental level, from tiniest distances to cosmological extents, that are intractable with classical computers but may benefit from quantum advantage. They have initiated, and continue to carry out, a vigorous program in theory, algorithm, and hardware co-design for simulations of relevance to the HEP mission. This Roadmap is an attempt to bring this exciting and yet challenging area of research to the spotlight, and to elaborate on what the promises, requirements, challenges, and potential solutions are over the next decade and beyond.

关键词： Quantum simulation