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The global monopole spacetime and its topological charge

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Chinese Physics B 2018年第3期27卷 146-152页

作者： Hongwei Tan Jinbo yang Jingyi Zhang Tangmei He Center for Astrophysics Guangzhou University Guangzhou 510006 China

We show that the global monopole spacetime is one of the exact solutions of the Einstein equations by treating the matter field as a non-linear sigma model, without the weak field approximation applied in the original derivation by Barriola and Vilenkin. Furthermore, we find the physical origin of the topological charge in the global monopole spacetime. Finally, we generalize the proposal which generates spacetime from thermodynamical laws to the case of spacetime with global monopole charge.

关键词： global monopole spacetime exact solution topological charge thermodynamics

Settled fast measurement of topological charge by direct extraction of plane wave from vortex beam

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Chinese Physics B 2021年第10期30卷 306-317页

作者： Xiao-Bo Yang Jin Hu School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China Institute of Information Engineering Chinese Academy of SciencesBeijing 100195China China Beijing Key Laboratory of Fractional Signals and Systems Beijing 100081China

A method of measuring the vortex beam topological charge(TC)is proposed based on a device that can directly extract the plane wave form from the vortex beam in which the different propagation angles of the plane waves are uniquely related to the different *** the TC can be obtained by simply comparing the energy values perceived by two fixed sensors in the detection location with the help of twin omnidirectional energy absorbers(OEAs).Because the settled detection relies only on the simple quantitative value at two fixed positions,neither pattern recognition nor field analysis procedure is applied,thus allowing faster *** features of the methodology are investigated,and the numerical simulations verify the feasibility and robustness of the system.

关键词： vortex beam topological charge settled measurement

Spin-orbit-locked hyperbolic polariton vortices carrying reconfigurable topological charges

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eLight 2022年第1期2卷 143-153页

作者： Mingsong Wang Guangwei Hu Saroj Chand Michele Cotrufo Yohannes Abate Kenji Watanabe Takashi Taniguchi Gabriele Grosso Cheng‑Wei Qiu Andrea Alù Photonics Initiative Advanced Science Research CenterCity University of New YorkNew York CityNY 10031USA Department of Electrical and Computer Engineering National University of SingaporeSingapore 116083Singapore Department of Physics and Astronomy The University of GeorgiaAthensGA 30602USA Research Center for Functional Materials National Institute for Materials ScienceTsukubaIbaraki 305‑0044Japan International Center for Materials Nanoarchitectonics National Institute for Materials ScienceTsukubaIbaraki 305‑0044Japan Physics Program Graduate CenterCity University of New YorkNew YorkNY 10016USA

The topological features of optical vortices have been opening opportunities for free-space and on-chip photonic technologies,e.g.,for multiplexed optical communications and robust information *** a parallel but disjoint effort,polar anisotropic van der Waals nanomaterials supporting hyperbolic phonon polaritons(HP2s)have been leveraged to drastically boost light-matter *** far HP2 studies have been mainly focusing on the control of their amplitude and scale *** we report the generation and observation of mid-infrared hyperbolic polariton vortices(HP2Vs)associated with reconfigurable topological ***-shaped gold disks coated with a flake of hexagonal boron nitride are exploited to tailor spin-orbit interactions and realise deeply subwavelength *** complex interplay between excitation spin,spiral geometry and HP2 dispersion enables robust reconfigurability of the associated topological *** results reveal unique opportunities to extend the application of HP2s into topological photonics,quantum information processing by integrating these phenomena with single-photon emitters,robust on-chip optical applications,sensing and nanoparticle manipulation.

关键词： Hyperbolic polariton vortex Light-matter interactions Spin-orbit interaction topological charge Reconfigurability

Study of topological Structure of Vacuum by Lattice QCD

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Communications in Theoretical Physics 2007年第3期47卷 535-538页

作者： WANG Zi-Qing Lü Xiao-Fu WANG Fan Department of Physics Sichuan University Chengdu 610064 China Department of Physics Nanjing University Nanjing 210093 China Institute of Theoretical Physics The Chinese Academy of Sciences Beijing 100080 China CCAST （World Laboratory） P.O. Box 8730 Beijing 100080 China

Overlap fermions and improved 5Li cooling are compared, which exhibits that these two filter methods can produce similar structures. Then the overlap fermions and improved 5Li cooling are combined to calculate the top... 详细信息

关键词： overlap fermions improved 5Li cooling topological charge structure of the vacuum instanton liquid model

Evolution of polarization singularities accompanied by avoided crossing in plasmonic system

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Chinese Physics B 2023年第1期32卷 305-310页

作者：彭一啸宋前举胡鹏崔大健向红韩德专 Chongqing University Chongqing 400044China School of Science Southwest University of Science and TechnologyMianyang 621010China Chongqing Key Laboratory of Core Optoelectronic Devices for Quantum Communication Chongqing Optoelectronics Research InstituteChongqing 400060China

The evolution of polarization singularities supported in a one-dimensional periodic plasmonic system is *** lateral inversion symmetry of the system,which breaks the in-plane inversion symmetry and up-down mirror symmetry simultaneously,yields abundant polarization states.A complete evolution process with geometry for the polarization states is *** the evolution,circularly polarized points(C points)can stem from 3 different *** addition to the previously reported processes occurring in an isolated band,a new type of C point appearing in two bands simultaneously due to the avoided band crossing,is *** the dielectric system with a similar structure which only supports at-Γbound states in the continuum(BICs),accidental BICs off theΓpoint are realized in this plasmonic *** work provides a new scheme of polarization manipulation for the plasmonic systems.

关键词： polarization singularities topological charge avoided crossing inversion symmetry

Composite optical vortices in noncollinear Laguerre–Gaussian beams and their propagation in free space

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Chinese Physics B 2008年第5期17卷 1743-1751页

作者：程科刘普生吕百达 Institute of Laser Physics and Chemistry Sichuan University

Taking two Laguerre-Gaussian beams with topological charge 1 = ±1 as an example, this paper studies the composite optical vortices formed by two noncollinear Laguerre-Gaussian beams with different phases, amplitudes, waist widths, off-axis distances, and their propagation in free space. It is shown by detailed numerical illustrative examples that the number and location of composite vortices at the waist plane are variable by varying the relative phase β, amplitude ratio η, waist width ratio ξ, or off-axis distance ratio μ. The net topological charge lnet is not always equal to the sum lsum of charges of the two component beams. The motion, creation and annihilation of composite vortices take place in the free-space propagation, and the net charge during the propagation remains unchanged and equals to the net charge at the waist plane.

关键词： composite optical vortex Laguerre-Gaussian beam topological charge creation and annihilation

Generation of elliptical airy vortex beams based on all-dielectric metasurface

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Chinese Physics B 2023年第2期32卷 347-353页

作者：薛晓菊徐弼军吴白瑞汪小刚俞昕宁林露李宏强 School of Science Zhejiang University of Science and TechnologyHangzhou 310023China Tongji University Shanghai 200092China Institute of Dongguan-Tongji University Dongguan 523808China

Elliptical airy vortex beams(EAVBs) can spontaneously form easily identifiable topological charge focal spots. They are used for topological charge detection of vortex beams because they have the abruptly autofocusing properties of circular airy vortex beams and exhibit unique propagation characteristics. We study the use of the dynamic phase and Pancharatnam–Berry phase principles for generation and modulation of EAVBs by designing complex-amplitude metasurface and phase-only metasurface, at an operating wavelength of 1500 nm. It is found that the focusing pattern of EAVBs in the autofocusing plane splits into |m| + 1 tilted bright spots from the original ring, and the tilted direction is related to the sign of the topological charge number m. Due to the advantages of ultra-thin, ultra-light, and small size of the metasurface, our designed metasurface device has potential applications in improving the channel capacity based on orbital angular momentum communication, information coding, and particle capture compared to spatial light modulation systems that generate EAVBs.

关键词： elliptical airy vortex beams(EAVBs) metasurface topological charge

Partially coherent vortex beams:Fundamentals and applications

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Science China(Physics,Mechanics & Astronomy) 2021年第2期64卷 32-50页

作者： Miao Dong ChengLiang Zhao YangJian Cai YuanJie Yang School of Physics University of Electronic Science and Technology of ChinaChengdu611731China School of Physical Science and Technology Soochow UniversitySuzhou215006China Shandong Provincial Engineering and Technical Centre of Light Manipulations&Shandong Provincial Key Laboratory of Optics and Photonic Device School of Physics and ElectronicsShandong Normal UniversityJinan250014China

It has been over 30 years since the concept of optical vortices was first proposed by Coullet et *** 1989,and the field of structured beams has grown *** the last two decades,partially coherent vortex beams(PCVBs)have received increasing interest in the fields of optical manipulation,optical communication,optical imaging,etc.,and great progress has been made in the area of the coherence singularities,generation methods,topological charge measurements,and promising applications of *** this review,we firstly outline the basic concepts of *** explicate the relationship between the coherence vortices and optical vortices,and the evolution behavior of optical vortices to coherence vortices is summarized in *** discuss a special form of coherence singularity,ring dislocation,mathematically and *** ring dislocation in the correlation functions under low coherence is dependent on the mode indices,which provide a feasible approach to measure mode indices of ***,we summarize the various methods for measuring the topological charge of PCVBs,highlight the measurement method based on the cross-correlation function,and a physical explanation on the relation between ring dislocation and topological charge is *** that,we review the recent advances on experimental generation of several kinds of ***,we give an overview on the potential applications of PCVBs.

关键词： coherence singularities coherence vortices vortex beams topological charge

Measuring orbital angular momentum of acoustic vortices based on Fraunhofer's diffraction

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Chinese Physics B 2020年第10期29卷 315-320页

作者： Chao-Fan Gong Jing-Jing Li Kai Guo Hong-Ping Zhou Zhong-Yi Guo School of Computer and Information Hefei University of TechnologyHefei 230009China

Acoustic vortex (AV) beam is triggering the significant research interest in information and communication sciences due to its infinite and mutual orthogonal orbital angular momentums (OAMs). Therefore, measuring the topological charges of an AV beams become a task with great significance. In this work, we present a Fraunhofer diffraction (FD) pattern of an AV beam that can be used to quantitatively detect the OAMs of AV beams. We both theoretically and numerically investigate the FD patterns of AV beams passing through a multipoint interferometer (MPI). It is demonstrated that the topological charges of the AV beams can be determined from the interference intensity patterns. The proposed method may pave the way to the practical applications of AV beams.

关键词： acoustic vortex multipoint interferometer(MPI) topological charge Fraunhofer diffraction(FD)