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Skyrmions in nanorings: a versatile platform for Skyrmionics

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arXiv 2023年

作者： Kechrakos, Dimitris Puliafito, Vito Riveros, Alejandro Liu, Jiahao Jiang, Wanjun Carpentieri, Mario Tomasello, Riccardo Finocchio, Giovanni Athens Greece Department of Electrical and Information Engineering Technical University of Bari Bari70125 Italy Escuela de Ingeniería Universidad Central de Chile Santiago8330601 Chile Department of Mathematical and Computer Sciences Physical Sciences and Earth Sciences University of Messina MessinaI-98166 Italy State Key Laboratory of Low-Dimensional Quantum Physics Department of Physics Tsinghua University Beijing100084 China Frontier Science Center for Quantum Information Tsinghua University Beijing100084 China College of Advanced Interdisciplinary Studies & Hunan Provincial Key Laboratory of Novel Nano-Optoelectronic Information Materials and Devices National University of Defense Technology Hunan Changsha410073 China

The dynamical properties of skyrmions can be exploited to build devices with new functionalities. Here, we first investigate a skyrmion-based ring-shaped device by means of micromagnetic simulations and Thiele’s equation. We subsequently show three applications scenarios: (1) a clock with tunable frequency that is biased with an electrical current having a radial spatial distribution, (2) an alternator, where the skyrmion circular motion driven by an engineered anisotropy gradient is converted into an electrical signal, and (3) an energy harvester, where the skyrmion motion driven by a thermal gradient is converted into an electrical signal, thus providing a heat recovery operation. We also show how to precisely tune the frequency and amplitude of the output electrical signals by varying material parameters, geometrical parameters, number and velocity of skyrmions, and we further prove the correct device functionality under realistic conditions given by room temperature and internal material defects. Our results open a new route for the realization of energy efficient nanoscale clocks, generators, and energy harvesters. © 2023, CC BY.

关键词： Clocks

Poison over troubled forwarders: a cache poisoning attack targeting DNS forwarding device 20

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Poison over troubled forwarders: a cache poisoning attack ta...

Proceedings of the 29th USENIX Conference on Security Symposium

作者： Xiaofeng Zheng Chaoyi Lu Jian Peng Qiushi Yang Dongjie Zhou Baojun Liu keyu Man Shuang Hao Haixin Duan Zhiyun Qian Tsinghua University and Qi An Xin Technology Research Institute Tsinghua University Qi An Xin Technology Research Institute State Key Laboratory of Mathematical Engineering and Advanced Computing University of California Riverside University of Texas at Dallas

ISBN: (纸本)9781939133175

In today's DNS infrastructure, DNS forwarders are devices standing in between DNS clients and recursive resolvers. The devices often serve as ingress servers for DNS clients, and instead of resolving queries, they pass the DNS requests to other servers. Because of the advantages and several use cases, DNS forwarders are widely deployed and queried by Internet users. However, studies have shown that DNS forwarders can be more vulnerable devices in the DNS *** this paper, we present a cache poisoning attack targeting DNS forwarders. Through this attack, attackers can inject rogue records of arbitrary victim domain names using a controlled domain, and circumvent widely-deployed cache poisoning defences. By performing tests on popular home router models and DNS software, we find several vulnerable implementations, including those of large vendors (e.g., D-Link, Linksys, dnsmasq and MS DNS). Further, through a nationwide measurement, we estimate the population of Chinese mobile clients which are using vulnerable DNS forwarders. We have been reporting the issue to the affected vendors, and so far have received positive feedback from three of them. Our work further demonstrates that DNS forwarders can be a soft spot in the DNS infrastructure, and calls for attention as well as implementation guidelines from the community.

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A review of cryptographic algorithm recognition technology for binary code

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Journal of Physics: Conference Series 2021年第1期1856卷

作者： Chenxia Zhao Fei Kang Ju Yang Hui Shu Zhengzhou University Zhengzhou Henan 450001 China State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou Henan 450001 China

Aiming at the cryptographic algorithm that may be contained in the binary program, combined with existing research results, several cryptographic algorithm identification techniques are analyzed, including control flow graphs, data flow graphs, feature matching, selection of command statistical attributes, and semantic-based behavior analysis. The recognition effects of related technologies are discussed respectively.

关键词：

Nonreciprocal Single-Photon Band Structure

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Physical Review Letters 2022年第20期128卷 203602-203602页

作者： Jiang-Shan Tang Wei Nie Lei Tang Mingyuan Chen Xin Su Yanqing Lu Franco Nori keyu Xia College of Engineering and Applied Sciences National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210023 China School of Physics Nanjing University Nanjing 210023 China RIKEN Quantum Computing Center RIKEN Cluster for Pioneering Research Wako-shi Saitama 351-0198 Japan Center for Joint Quantum Studies and Department of Physics School of Science Tianjin University Tianjin 300350 China School of Electronic Science and Engineering Nanjing University Nanjing 210023 China Physics Department The University of Michigan Ann Arbor Michigan 48109-1040 USA Jiangsu Key Laboratory of Artificial Functional Materials Nanjing University Nanjing 210023 China Key Laboratory of Intelligent Optical Sensing and Manipulation (Nanjing University) Ministry of Education Nanjing 210023 China

We study a single-photon band structure in a one-dimensional coupled-resonator optical waveguide that chirally couples to an array of two-level quantum emitters (QEs). The chiral interaction between the resonator mode and the QE can break the time-reversal symmetry without the magneto-optical effect and an external or synthetic magnetic field. As a result, nonreciprocal single-photon edge states, band gaps, and flat bands appear. By using such a chiral QE coupled-resonator optical waveguide system, including a finite number of unit cells and working in the nonreciprocal band gap, we achieve frequency-multiplexed single-photon circulators with high fidelity and low insertion loss. The chiral QE-light interaction can also protect one-way propagation of single photons against backscattering. Our work opens a new door for studying unconventional photonic band structures without electronic counterparts in condensed matter and exploring its applications in the quantum regime.

关键词： Cavity quantum electrodynamics Light propagation, transmission & absorption Quantum description of light-matter interaction Topological effects in photonic systems

Stabilization of continuous-time Markov/semi-Markov jump linear systems via finite data-rate feedback

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arXiv 2021年

作者： Wang, Jingyi Feng, Jianwen Xu, Chen Wu, Xiaoqun Lü, Jinhu College of Mathematics and Statistics Shenzhen University Shenzhen518060 China School of Mathematics and Statistics Hubei Key Laboratory of Computational Science Wuhan University Wuhan China State Key Laboratory of Software Development Environment School of Automation Science and Electrical Engineering Beijing Advanced Innovation Center for Big Data and Brain Computing Beihang University Beijing China

This paper investigates almost sure exponential stabilization of continuous-time Markov jump linear systems (MJLSs) under communication data-rate constraints by introducing sampling and quantization into the feedback control. Different from previous works, the sampling times and the jump times are independent of each other in this paper. The quantization is recursively adjusted on the sampling time, and its updating strategy does not depend on the switching in a sampling interval. In other words, the explicit value of the switching signal in a sampling interval is not necessary. The numerically testable condition is developed to ensure almost sure exponential stabilization of MJLSs under the proposed communication and control protocols. We also drop the assumption of stabilizability of all individual modes required in previous works about the switched systems. Moreover, we extend the result to the case of continuous-time semi-Markov jump linear systems (semi-MJLSs) via the semi-Markov kernel approach. Finally, some numerical examples are presented to illustrate the effectiveness on stabilization of the proposed communication and control *** Codes 93D15 © 2021, CC BY.

关键词： Markov processes

A Security-Sensitive Function Mining Framework for Source Code 1

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5th International Conference on Artificial Intelligence and Security, ICAIS 2019

作者： Chen, Lin Yang, Chunfang Liu, Fenlin Gong, Daofu Ding, Shichang Zhengzhou Science and Technology Institute Zhengzhou450001 China State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou450001 China University of Göttingen Goldschmidtstr. 7 Göttingen37077 Germany

ISBN: (数字)9783030242688

ISBN: (纸本)9783030242671

The security-sensitive functions can be effectively used to improve the efficiency of vulnerability mining techniques, but mining security-sensitive functions of the large-scale code base is difficult. An automatic mining framework for security-sensitive functions is proposed. Firstly, a class of high-resolution code features is used to extract suspected security-sensitive function sets, and then a class of code features is applied to measure the sensitivity of each suspected security-sensitive function. Ultimately, the final security-sensitive function set is ensured based on the measurement result. Established along the framework, a mining algorithm for a type security-sensitive function is proposed. Through the mining experiments on three well-known open source codes, the performance of this algorithm is better than the existing methods. © 2019, Springer Nature Switzerland AG.

关键词： Open source software

Moment-Based Space-Variant Shack–Hartmann Wavefront Reconstruction

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SSRN

SSRN 2023年

作者： Feng, Fan Liang, Chen Chen, Dongdong Du, Ke Yang, Runjia Lu, Chang Chen, Shumin He, Wenting Xu, Pingyong Chen, Liangyi Tao, Louis Mao, Heng Center for Bioinformatics National Laboratory of Protein Engineering and Plant Genetic Engineering School of Life Sciences Peking University Beijing100871 China GBA Institute of Collaborative Innovation Guangzhou510300 China LMAM School of Mathematical Sciences Peking University Beijing100871 China School of Software and Microelectronics Peking University Beijing100871 China State Key Laboratory of Membrane Biology Beijing Key Laboratory of Cardiometabolic Molecular Medicine Institute of Molecular Medicine Center for Life Sciences College of Future Technology Peking University Beijing100871 China School of Instrumentation and Optoelectronic Engineering Beihang University Beijing100191 China Key Laboratory of RNA Biology Institute of Biophysics Chinese Academy of Sciences Beijing100101 China National Laboratory of Biomacromolecules Institute of Biophysics Chinese Academy of Sciences Beijing100101 China PKU-IDG/McGovern Institute for Brain Research Beijing100871 China Beijing Academy of Artificial Intelligence Beijing100871 China Center for Quantitative Biology Peking University Beijing100871 China Beijing Advanced Innovation Center for Imaging Theory and Technology Capital Normal University Beijing100871 China

Based on image moment theory, an approach for space-variant Shack–Hartmann wavefront reconstruction is presented in this article. The relation between the moment of a pair of subimages and the local transformation coefficients is derived. The square guide ‘star’ is used to obtain a special solution from this relation. The moment-based wavefront reconstruction has a reduced computational complexity compared to the iteration-based algorithm. Image restorations are executed by the tiling strategy with 5 × 5 PSFs as well as the conventional strategy with a global average PSF. Visual and quantitative evaluations support our approach. © 2023, The Authors. All rights reserved.

关键词： Adaptive optics

Moment-based Space-variant Shack-Hartmann Wavefront Reconstruction

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arXiv 2023年

This article presents an approach for space-variant Shack-Hartmann wavefront reconstruction based on image moment theory. We derive the relation between the moment of a pair of subimages and the local transformation coefficients. A special solution is obtained from this relation using the square guide 'star'. Our moment-based wavefront reconstruction has reduced computational complexity compared to the iteration-based algorithm. We execute image restorations using both the tiling strategy with 5 × 5 PSFs and the conventional strategy with a global average PSF. Our approach is supported by visual and quantitative evaluations. © 2023, CC BY-NC-SA.

关键词： Adaptive optics

Virasoro Generators in the Fibonacci Model Tensor Network — Tackling Finite Size Effects

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arXiv 2022年

作者： Zeng, Xiangdong Wang, Ruoshui Shen, Ce Hung, Ling-Yan State Key Laboratory of Surface Physics Fudan University Shanghai200433 China Department of Physics Center for Field Theory and Particle Physics Fudan University Shanghai200433 China Cornell University IthacaNY14853 United States Institute for Advanced Study Tsinghua University Beijing100084 China Institute for Nanoelectronic devices and Quantum computing Fudan University Shanghai200433 China Yau Mathematical Sciences Center Tsinghua University Beijing100084 China

In this paper, we extend the method implementing Virasoro operators in a tensor network we proposed in [1] and test it on the Fibonacci model, which is known to suffer from far more finite size effects. To pick up the "seed" state that would flow to the stress tensor in the thermodynamic limit, we make use of the topological idempotent that projects the transfer matrix to the trivial sector. Combined with an optimization method, the seed state can be identified. We demonstrate that the descendant states in the Fibonacci model can be correctly generated with this approximate stress tensor, giving further evidence that the method applies more generally. Copyright © 2022, The Authors. All rights reserved.

关键词： Stress tensor