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Localization of chiral edge states by the non-Hermitian skin effect

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arXiv 2023年

作者： Liu, Gui-Geng Mandal, Subhaskar Zhou, Peiheng Xi, Xiang Banerjee, Rimi Hu, Yuan-Hang Wei, Minggui Wang, Maoren Wang, Qiang Gao, Zhen Chen, Hongsheng Yang, Yihao Chong, Yidong Zhang, Baile Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link Singapore637371 Singapore National Engineering Research Center of Electromagnetic Radiation Control Materials State Key Laboratory of Electronic Thin Film and Integrated Devices University of Electronic Science and Technology of China Chengdu610054 China Department of Electrical and Electronic Engineering Southern University of Science and Technology Shenzhen518055 China School of Physics Collaborative Innovation Center of Advanced Microstructures Nanjing University Jiangsu Nanjing210093 China Interdisciplinary Center for Quantum Information State Key Laboratory of Modern Optical Instrumentation ZJU-Hangzhou Global Science and Technology Innovation Center College of Information Science and Electronic Engineering Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang ZJU-UIUC Institute Zhejiang University Hangzhou310027 China Centre for Disruptive Photonic Technologies The Photonics Institute Nanyang Technological University 50 Nanyang Avenue Singapore639798 Singapore

Quantum Hall systems host chiral edge states extending along the one-dimensional boundary of any two-dimensional sample. In solid state materials, the edge states serve as perfectly robust transport channels that produce a quantised Hall conductance;due to their chirality, and the topological protection by the Chern number of the bulk bandstructure, they cannot be spatially localized by defects or disorder. Here, we show experimentally that the chiral edge states of a lossy quantum Hall system can be localized. In a gyromagnetic photonic crystal exhibiting the quantum Hall topological phase, an appropriately structured loss configuration imparts the edge states’ complex energy spectrum with a feature known as point-gap winding. This intrinsically non-Hermitian topological invariant is distinct from the Chern number invariant of the bulk (which remains intact) and induces mode localization via the "non-Hermitian skin effect". The interplay of the two topological phenomena – the Chern number and point-gap winding – gives rise to a non-Hermitian generalisation of the paradigmatic Chern-type bulk-boundary correspondence principle. Compared to previous realisations of the non-Hermitian skin effect, the skin modes in this system have superior robustness against local defects and disorders. Copyright © 2023, The Authors. All rights reserved.

关键词： Topology

Create Manufacturing Service with GAN

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Create Manufacturing Service with GAN

2019 IEEE International Conference on Smart Manufacturing, Industrial and Logistics engineering, SMILE 2019

作者： Chen, Shengkai Fang, Shuiliang Tang, Renzhong Key Lab. of Advanced Manufacturing Technology of Zhejiang Province College of Mechanical Engineering Zhejiang University Hangzhou China State Key Laboratory of Fluid Power Transmission and Control College of Mechanical Engineering Zhejiang University Hangzhou China

ISBN: (纸本)9781538679982

A generative adversarial network based manufacturing service instance generator is proposed in this paper. During the training of the generative adversarial network model, we adopt Word2Vec model to represent manufacturing services in the form of numerical vectors. The accuracy of the generator gets 0.76 after training, and the synthesized data are good enough to extend the current datasets for the further study on manufacturing services. © 2019 IEEE.

关键词： Generative adversarial networks

An Advanced control Strategy for Bidirectional Isolated Three Phase AC/DC Dual-Active-Bridge Converter in Hybrid Microgrid

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An Advanced Control Strategy for Bidirectional Isolated Thre...

IEEE Conference on Energy Internet and Energy System Integration (EI2)

作者： Dongxin Guo Panbao Wang Jiansheng Kong Jinjie Tian Chunguang Ren Xiangqi Meng Yanbing Jia Yue Qin Zeqi Wang Shanxi Key Lab. of Power System Operation and Control Taiyuan University of Technology Taiyuan China Harbin Institute of Technology Harbin China Datong Power Supply Company State Grid Shanxi Electric Power Company Datong China School of Electrical and Power Engineering Taiyuan University of Technology Taiyuan China

ISBN: (纸本)9781665434263

This paper proposes an advanced control strategy consisting of current stress optimization based on triple-phase-shifting (TPS) modulation for front-end DAB converter and 33% PWM method for back-end three-phase full bridge inverter. Compared with the traditional phase shift control, the control strategy proposed for the front-end DAB converter achieves linear control and significantly reduces current stress. In addition, it reduces the DC-Link capacitance, which improves the safety of the equipment. The 33% modulation method adopted by the full bridge inverter at the back-end reduces the switching loss of semiconductor devices. The principle, derivation and realization of the proposed control strategy are described in detail. Simulation results are presented to validate the effectiveness of the proposed strategy.

关键词： Solid modeling Phase modulation Switching frequency Bridge circuits Switching loss System integration Capacitance

Demonstration of broadband topological slow light

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arXiv 2022年

作者： Chen, Fujia Xue, Haoran Pan, Yuang Wang, Maoren Hu, Yuanhang Zhang, Li Chen, Qiaolu Han, Song Liu, Gui-Geng Gao, Zhen Zhou, Peiheng Yin, Wenyan Chen, Hongsheng Zhang, Baile Yang, Yihao Interdisciplinary Center for Quantum Information State Key Lab. of Modern Optical Instrumentation College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China ZJU-Hangzhou Global Science and Technology Innovation Center Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang ZJU-UIUC Institute Zhejiang University Hangzhou310027 China Jinhua Institute of Zhejiang University Zhejiang University Jinhua321099 China Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link Singapore637371 Singapore Centre for Disruptive Photonic Technologies The Photonics Institute Nanyang Technological University 50 Nanyang Avenue Singapore639798 Singapore National Engineering Research Center of Electromagnetic Radiation Control Materials State Key Laboratory of Electronic Thin Film and Integrated Devices University of Electronic Science and Technology of China Chengdu610054 China Department of Electrical and Electronic Engineering Southern University of Science and Technology Shenzhen518055 China

Slow-light devices are able to significantly enhance light-matter interaction due to the reduced group velocity of light, but a very low group velocity is usually achieved in a narrow bandwidth, accompanied by extreme sensitivity to imperfections that causes increased disorder-induced attenuation. Recent theories have suggested an ideal solution to this problem—unidirectional chiral photonic states, previously discovered in structures known as photonic topological insulators, not only resist backscattering from imperfections but can also be slowed down in the entire topological bandgap with multiple windings in the Brillouin zone. Here, we report on the experimental demonstration of broadband topological slow light in a photonic topological insulator. When coupled with periodic resonators that form flat bands, the chiral photonic states can wind many times around the Brillouin zone, achieving an ultra-low group velocity in the entire topological bandgap. This demonstration extends the scope of topological photonics into slow light engineering, and opens a unique avenue in the dispersion manipulation of chiral photonic states. © 2022, CC BY.

关键词： Slow light

Low doping strategy in amorphous alumina: Harnessing oxygen vacancies and retaining structural disorder for advanced low-temperature ceramics fuel cell

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Journal of Colloid and Interface Science 2025年 699卷

作者： Muhammad Ahsan Masood Muhammad Shahid Sharif Sajid Rauf Zuhra Tayyab M.A.K. Yousaf Shah Yibin Tian Aljawhara H. Almuqrin Bushra Bibi College of Mechatronics and Control Engineering & State Key Lab of Radio Frequency Heterogeneous Integration Shenzhen University Shenzhen 518060 China Energy Storage Joint Research Center School of Energy and Environment Southeast University Nanjing 210096 People's Republic of China Department of Physics College of Science Princess Nourah Bint Abdulrahman University P.O. Box 84428 Riyadh 11671 Saudi Arabia

Amorphous alumina has emerged as a compelling candidate for ceramic fuel cells (CFCs) due to its intrinsic structural disorder, which promotes low-energy ionic transport pathways. However, generating oxygen vacancies without altering the amorphous nature is critical for practical applications. In this study, we report a low-doping strategy using cobalt (3 % and 6 %) to enhance the ionic conductivity of amorphous alumina without compromising its disordered structure. Advanced structural and chemical characterizations confirm the retention of the amorphous phase and reveal the role of cobalt doping in inducing oxygen vacancies, respectively. Electrochemical performance evaluations demonstrate a significant leap in power density of the fuel cell, with pure alumina delivering 512 mW cm −2 , while 3 % and 6 % cobalt-doped alumina (3-CAO & 6-CAO) achieve 672 mW cm −2 and 773 mW cm −2 , respectively, at 550 °C. Enhanced ionic conductivity, reaching 0.17 S cm −1 for 6-CAO compared to 0.078 S cm −1 for pure alumina at 550 °C, underscores the efficacy of this approach. The functionality of dual oxidation states of cobalt and alternating oxidation states of Co between Co 2+ and Co 3+ assists subcutaneously in generating oxygen vacancies that enhance ionic transport while retaining the beneficial disorder of the amorphous matrix. The dominant presence of proton conductivity in 6-CAO electrolytes and their experimental confirmation assures the superior electrolytic functionality. This innovative low-doping strategy advances high-performance low-temperature CFCs, showcasing the potential of disordered ionic conductors for next-generation energy technologies.

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A novel energy-saving train operation strategy based on particle swarm algorithms

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A novel energy-saving train operation strategy based on part...

Chinese Automation Congress (CAC)

作者： Hao Wang Yuxuan Li Hongli Zhao Xinjun Gao China Railway Siyuan Survey and Designing Group CO. LTD Wuhan China State Key Lab. of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China School of Electronics and Information Engineering Beijing Jiaotong University Beijing P.R China Sciences Signal and Communication Research Institute China Academy of Railway Beijing China

ISBN: (纸本)9781665426480

To effectively reduce the energy consumption of urban rail transit trains and optimize the operation strategy, based on the dynamic model of the urban rail transit train, the energy consumption model of four-stage manipulation strategy is constructed respectively, and the particle swarm optimization algorithm is used to solve the model. In this paper, an Atype train with four driving and two pallets are selected as the research object, and a case design is carried out on a flat ramp. The operation strategy is analyzed for the difference between vehicle traction energy consumption, regenerative braking energy storage, and total energy consumption. The corresponding speed-distance curve is obtained by simulation. The results show that the four-stage control strategy is generally helpful to achieve better energy-saving optimization effects.

关键词： Rails Energy consumption Heuristic algorithms Force Particle swarm optimization Vehicle dynamics Pallets

Breakdown of effective-medium theory by a photonic spin Hall effect

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arXiv 2023年

作者： Yuan, Shuaijie Zhou, Xinxing Chen, Yu Zhong, Yuhan Sheng, Lijuan Hu, Hao Chen, Hongsheng Kaminer, Ido Lin, Xiao Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Synergetic Innovation Center for Quantum Effects and Applications School of Physics and Electronics Hunan Normal University Changsha410081 China International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology Engineering Technology Research Center for 2D Material Information Function Devices and Systems of Guangdong Province Institute of Microscale Optoelectronics Shenzhen University Shenzhen518060 China Interdisciplinary Center for Quantum Information State Key Laboratory of Extreme Photonics Instrumentation ZJU-Hangzhou Global Scientific and Technological Innovation Center Zhejiang University Hangzhou310027 China International Joint Innovation Center The Electromagnetics Academy Zhejiang University Zhejiang University Haining314400 China School of Electrical and Electronic Engineering Nanyang Technological University 50 Nanyang Avenue Singapore639798 Singapore Key Laboratory of Radar Imaging and Microwave Photonics Ministry of Education College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics Nanjing211106 China Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang Jinhua Institute of Zhejiang University Zhejiang University Jinhua321099 China Shaoxing Institute of Zhejiang University Zhejiang University Shaoxing312000 China Department of Electrical Engineering Technion-Israel Institute of Technology Haifa32000 Israel

Effective-medium theory pertains to the theoretical modelling of homogenization, which aims to replace an inhomogeneous structure of subwavelength-scale constituents with a homogeneous effective medium. The effective-medium theory is fundamental to various realms, including electromagnetics and material science, since it can largely decrease the complexity in the exploration of light-matter interactions by providing simple acceptable approximation. Generally, the effective-medium theory is thought to be applicable to any all-dielectric system with deep-subwavelength constituents, under the condition that the effective medium does not have a critical angle, at which the total internal reflection occurs. Here we reveal a fundamental breakdown of the effective-medium theory that can be applied in very general conditions: showing it for deep-subwavelength all-dielectric multilayers even without critical angle. Our finding relies on an exotic photonic spin Hall effect, which is shown to be ultra-sensitive to the stacking order of deep-subwavelength dielectric layers, since the spin-orbit interaction of light is dependent on slight phase accumulations during the wave propagation. Our results indicate that the photonic spin Hall effect could provide a promising and powerful tool for measuring structural defects for all-dielectric systems even in the extreme nanometer scale. Copyright © 2023, The Authors. All rights reserved.

关键词： Spin Hall effect

Applications of Game Theory in Vehicular Networks: A Survey

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arXiv 2021年

作者： Sun, Zemin Liu, Yanheng Wang, Jian Li, Guofa Anil, Carie Li, Keqiang Guo, Xinyu Sun, Geng Tian, Daxin Cao, Dongpu College of Computer Science and Technology Jilin University Changchun130012 China Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education Jilin University Changchun130012 China Institute of Human Factors and Ergonomics College of Mechatronics and Control Engineering Shenzhen University Guangdong Shenzhen518060 China School of Computer Science and Engineering VIT-AP Andhra Pradesh Amaravati522237 India College of Engineering Nanjing Agricultural University Nanjing210031 China State Key Laboratory of Automotive Safety and Energy Department of Automotive Engineering Tsinghua University Beijing100084 China Beijing Advanced Innovation Center for Big Data and Brain Computing Beijing Key Laboratory for Cooperative Vehicle Infrastructure Systems and Safety Control School of Transportation Science and Engineering Beihang University Beijing100191 China Waterloo Cognitive Autonomous Driving Lab University of Waterloo N2L 3G1 Canada

In the Internet of things (IoT) era, vehicles and other intelligent components in an intelligent transportation system (ITS) are connected, forming vehicular networks (VNs) that provide efficient and safe traffic and ubiquitous access to various applications. However, as the number of nodes in an ITS increases, it is challenging to satisfy a varied and large number of service requests with different quality of service (QoS) and security requirements in highly dynamic VNs. Intelligent nodes in VNs can compete or cooperate for limited network resources to achieve the objective for either an individual or a group. Game theory (GT), a theoretical framework designed for strategic interactions among rational decision makers sharing scarce resources, can be used to model and analyze individual or group behaviors of communicating entities in VNs. This paper primarily surveys the recent developments of GT in solving various challenges of VNs. This survey starts with an introduction to the background of VNs. A review of GT models studied in the VNs is then introduced, including the basic concepts, classifications, and applicable vehicular issues. After discussing the requirements of VNs and the motivation of using GT, a comprehensive literature review on GT applications in dealing with the challenges of current VNs is provided. Furthermore, recent contributions of GT to VNs that are integrated with diverse emerging 5G technologies are surveyed. Finally, the lessons learned are given, and several key research challenges and possible solutions of applying GT in VNs are outlined. Copyright © 2021, The Authors. All rights reserved.

关键词： Quality of service

A Novel Framework to Collect Use Cases for the Evaluation of the Adaptability to Future Sustainable Transportation of IEC Standard System

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A Novel Framework to Collect Use Cases for the Evaluation of...

Information Science, Computer Technology and Transportation (ISCTT), International Conference on

作者： Jiahong Jin Feng Ni Lili Li Lizong Zhang Wei Xiao Xinmei Yuan State Grid Shaoxing Power Supply Company Shaoxing China State Grid Electric Power Research Institute Nanjing China Sichuan Energy Internet Research Institute Chengdu China College of Automotive Engineering State Key Lab. of Automotive Simulation and Control Jilin University Changchun China

ISBN: (数字)9781728185750

ISBN: (纸本)9781728185767

With the development of modern technologies and the environmental requirements, the revolution of sustainable transport systems in the future is inevitable. Standardization plays a key role in providing the ability of information sharing which will be required to enable the development of new applications for a future sustainable transport system. The collection of use cases is a fundamental step to comprehensively analyze the standardization requirements for future sustainable transport. In this paper, the enablers of future transport systems are found, a system model of future sustainable transport is proposed. Based on the framework of the combination of enablers and transport system model, use cases are given, and the aspects required to be focused for future sustainable transport standardization with priorities become clearer.

关键词： Adaptation models Information science Transportation IEC Information management IEC Standards Standards