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On the Riemann–Hilbert problem for the reverse space-time nonlocal Hirota equation with step-like initial data

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Communications in Theoretical physics 2025年第2期77卷 32-40页

作者： Bei-Bei Hu Ling Zhang Zu-Yi Shen Ji Lin School of Mathematics and Finance Chuzhou University applied Mathematics Research center Chuzhou University department of physics Zhejiang Normal University

In this paper, we use the Riemann–Hilbert(RH) method to investigate the Cauchy problem of the reverse space-time nonlocal Hirota equation with step-like initial data: q(z, 0) = o(1) as z →-∞ and q(z, 0) = δ + o(1) as z → ∞, where δ is an arbitrary positive constant. We show that the solution of the Cauchy problem can be determined by the solution of the corresponding matrix RH problem established on the plane of complex spectral parameter λ. As an example, we construct an exact solution of the reverse space-time nonlocal Hirota equation in a special case via this RH problem.

关键词： nonlocal Hirota equation Cauchy problem Riemann-Hilbert problem step-like initial data

Overcoming bandwidth limitations in space-coiled acoustic metamaterials through inclined perforated plate design

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Chinese physics B 2025年第1期34卷 374-379页

作者： Jixin Liu Fengmin Wu Ting Li Junjun Wang Xinye Zou Dong Zhang department of applied physics School of ScienceHarbin University of Science and TechnologyHarbin 150080China Key Laboratory of Modern Acoustics(MOE) Department of PhysicsCollaborative Innovation Center of Advanced MicrostructureNanjing UniversityNanjing 210093China Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093China

Traditional space-coiled acoustic metamaterials have been widely used in the fields of low-frequency sound absorption and noise ***,they have limitations in terms of low-frequency absorption bandwidth,and the weak coupling effect under complex coiled structures also limits their *** this work,we introduce the composite structure changing the characteristic impedance of acoustic metamaterials to enhance the coupling ***,the perforated plates with inclined design instead of traditional partitions greatly improve the sound *** model and method designed in this paper show significant innovation in enhancing low-frequency absorption performance.

关键词： metamaterials composite structure over-damped modes coupling sound absorption

New Taub-NUT black holes with massive spin-2 hair

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Science China(physics,Mechanics & Astronomy) 2025年第2期68卷 51-58页

作者： Yu-Qi Chen Hai-Shan Liu center for Joint Quantum Studies and department of physics School of ScienceTianjin UniversityTianjin 300350China

We consider Einstein gravity extended with quadratic curvature invariants,within which the well-known Ricci-flat Taub-NUT black hole remains a *** analysis of the unstable Lichnerowicz modes in the Taub-NUT background enables us to identify the mass and NUT parameters(m,n)where new Taub-NUT black holes can *** then adopt numerical techniques to construct these new Taub-NUT black holes,which bifurcate away from the Ricci-flat *** the Ricci-flat Taub-NUT,there can exist two new black holes for an appropriate given temperature,making it a total of three if we include the Ricci-flat one.

关键词： higher derivative gravity black hole solution Taub-NUT spacetime

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Supersymmetric hybrid inflation in light of CMB experiments and swampland conjectures

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Chinese physics C 2025年第1期49卷 114-126页

作者： Waqas Ahmed Shabbar Raza center for Fundamental physics and School of Mathematics and physics Hubei Polytechnic UniversityHuangshi 435003China department of physics Federal Urdu University of ArtsScience and TechnologyKarachi 75300Pakistan

In this study,we revisit supersymmetric(SUSY)hybrid inflation within the context of considering the latest Cosmic Microwave Background(CMB)observations and swampland *** demonstrate that SUSY hybrid inflation remains consistent with Planck 2018 data when radiative,soft mass,and supergravity(SUGRA)corrections are applied to the scalar *** is commonly perceived that SUSY hybrid inflation with a minimal Kahler potential results in a gauge symmetry breaking scale M of O(10^(15))GeV,leading to issues with the proton decay *** our analysis,we introduce a novel parameter space that alleviates the proton decay issue by achieving M~10^(16) GeV with M_(S)^(2)*** scenario necessitates a soft SUSY breaking scale|M_(S)|■10^(6) ***,we find that the tensor-to-scalar ratio r spans from 10^(-16) to 10^(-6),indicating a very small *** small ratio allows the modified swampland criteria to hold,although satisfying the trans-Planckian censorship conjecture(TCC)remains *** address this,we also explo non-minimal Kahler *** fixing the spectral index at n_(S)=0.9665,consistent with the central value of Planck 2018 data,and setting M=2×10^(16)GeV,we present our *** show that the canonical measure of primordial gravitational waves,r,for M_(S)=1 TeV,m_(3/2)=1 TeV,and k_(S)<0 for N=1 and N=2,ranges from 10^(-5) to 0.01,rendering it detectable by Planck and upcoming experiments such as LiteBIRD,Simons Observatory,PRISM,PIXIE,CORE,CMB-S4,and ***,we outline the parametric space and provide benchmark points for the non-minimal case to ensure compatibility with both the modified swampland conjecture and TCC.

关键词： suppersymmetry hybrid inflation swampland conjectures

Toward Analytical Homogenized Relaxation Modulus for Fibrous Composite Material with Reduced Order Homogenization Method

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Computers, Materials & Continua 2025年第1期82卷 193-222页

作者： Huilin Jia Shanqiao Huang Zifeng Yuan HEDPS Center for Applied Physics and Technology(CAPT)Department of Mechanics and Engineering SciencePeking UniversityBeijing100871China State Key Laboratory for Turbulence and Complex Systems Peking UniversityBeijing100871China

In this manuscript,we propose an analytical equivalent linear viscoelastic constitutive model for fiber-reinforced composites,bypassing general computational *** method is based on the reduced-order homogenization(ROH)*** ROH method typically involves solving multiple finite element problems under periodic conditions to evaluate elastic strain and eigenstrain influence functions in an‘off-line’stage,which offers substantial cost savings compared to direct computational homogenization *** to the unique structure of the fibrous unit cell,“off-line”stage calculation can be eliminated by influence functions obtained *** the standard solid model to the ROH method enables the creation of a comprehensive analytical homogeneous viscoelastic constitutive *** method treats fibrous composite materials as homogeneous,anisotropic viscoelastic materials,significantly reducing computational time due to its analytical *** approach also enables precise determination of a homogenized anisotropic relaxation modulus and accurate capture of various viscoelastic responses under different loading *** sets of numerical examples,including unit cell tests,three-point beam bending tests,and torsion tests,are given to demonstrate the predictive performance of the homogenized viscoelastic ***,the model is validated against experimental measurements,confirming its accuracy and reliability.

关键词： Homogenized relaxation modulus viscoelastic standard solid model reduced order homogenization fibrous composite material

Strong coupling between a quasi-two-dimensional perovskite and a honeycomb plasmonic nanocone array

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photonics Research 2025年第1期13卷 80-86页

作者： ZIXUAN SONG XUEXUAN HUANG LINGYAO LI LEYI ZHAO JIAMIN XIAO JIAZHI YUAN ZHIHANG WANG CHENGHAO BI WENXIN WANG Qingdao Innovation and Development center of Harbin Engineering University College of physics and Optoelectronic Engineering Harbin Engineering University department of applied physics The Hong Kong Polytechnic University

Recently organic-inorganic perovskite has been established as a promising platform for achieving room temperature exciton-polaritons, attributable to its superior optical coherence and robust exciton binding ***, when interfaced with metallic surfaces, the rapid degradation and quenching effect in perovskite have presented significant challenges, which critically hinders the exploration of light-matter interactions within metallic plasmonic structures. In this study, we report a quasi-two-dimensional lead halide perovskite that demonstrates a pronounced strong coupling phenomenon within an array of aluminum nanocones. The investigated quasi-two-dimensional perovskite structure exhibits high photoluminescence quantum efficiency and improved stability against metallic-induced degradation. Interestingly, the periodical arraying in honeycomb formation of plasmonic structure has advantages in angle-dependent dispersions and the loss neutralizing effectively. Besides,the plasmonic cone lattice characterized by its collective surface lattice resonance, features an exceptionally small mode volume and high quality, enhancing its interaction with the perovskite. A significant Rabi splitting of243 meV is observed at an incident angle of 30°. The dynamics of the Rabi oscillation is revealed by transient absorption spectra and theoretically analyzed by cavity quantum electrodynamics. This advancement in polariton research paves the way for novel applications, including quantum sources, enhanced photon-electron conversion efficiencies, and low-threshold lasing.

关键词： Cavity quantum electrodynamics Light matter interactions Optical constants Quantum efficiency Surface plasmon resonance Ti:sapphire lasers

Spin magnetization in unconventional antiferromagnets with collinear and non-collinear spins

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Science China(physics,Mechanics & Astronomy) 2025年第04期Mechanics & Astronomy) .卷 165-174页

作者： Lun-Hui Hu Song-Bo Zhang center for Correlated Matter and School of physics Zhejiang University department of applied physics School of Science Aalto University Hefei National Laboratory International center for Quantum Design of Functional Materials (ICQD) University of Science and Technology of China

Unconventional antiferromagnets(AFMs) with non-relativistic spin-splitting, such as the recently discovered altermagnet, have recently gained significant interest due to their potential for novel quantum phenomena and spintronic applications. The compensated magnetization in unconventional AFMs is protected by spin-space symmetries. In this work, we explore the symmetrybreaking effects and identify three distinct mechanisms for inducing net spin magnetizations in unconventional AFMs with collinear or non-collinear spins:(1) finite size effect,(2) extrinsic spin canting effect, and(3) irradiation with circularly polarized light. We show that the induced spin magnetizations are controllable and manifest as diverse intriguing phenomena. For the finite size system, the confined direction of a two-dimensional AM creates quantum-well-like subbands that determine the spin magnetization. This effect can be experimentally probed by measuring the spin density of states and the spin-polarization of Andreev-bound states within planar Josephson junctions. In the case of spin canting effect, it leads to peculiar anisotropic and non-monotonic behaviors in the superconducting proximity effect. Lastly, with circularly polarized light, spin magnetization is driven by the polarized light and the chirality of non-collinear magnetic order, thus offering a direct means of detecting the chirality of magnetic order in real materials. Our findings provide valuable insight into understanding and probing the spin magnetization in unconventional AFM materials.

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Decision making module based on stochastic magnetic tunnel junctions

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Science China(physics,Mechanics & Astronomy) 2025年第1期68卷 198-205页

作者： Yifan Miao Li Zhao Yajun Zhang Zhe Yuan center for Advanced Quantum Studies and department of physics Beijing Normal UniversityBeijing 100875China Institute for Nanoelectric Devices and Quantum Computing Fudan UniversityShanghai 200433China Interdisciplinary center for Theoretical physics and Information Sciences Fudan UniversityShanghai 200433China

In biological neural systems,noise is ubiquitous but does not affect the correct decisions made in the complex cognitive ***-making in biological neural system is typically achieved by accumulating input information over a period of *** by recent developments in neurosciences,we design a decision-making module based on spintronic devices,utilizing superparamagnetic tunnel junctions as artificial *** feasibility of this decision-making module is verified through circuit *** a multi-layer perceptron as an example,the module significantly improves the accuracy of the perceptron in the handwritten digit recognition ***,the spintronic decision-making module offers advantages over the conventional pooling methods,such as adaptive decision time,high performance and the absence of analog-to-digital *** decision-making module is flexible to be integrated into artificial neural networks and provides a general yet effective solution to enhance performance against device noise.

关键词： neuromorphic computing spintronics magnetic tunnel junction neural networks

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Anisotropic transport properties and topological Hall effect in the annealed kagome antiferromagnet FeGe

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Science China(physics,Mechanics & Astronomy) 2025年第3期68卷 153-160页

作者： Jiajun Ma Chenfei Shi Yantao Cao Yuwei Zhang Yazhou Li Jiaxing Liao Jialu Wang Wenhe Jiao Hanjie Guo Chenchao Xu Shixun Cao Jianhui Dai Jin-Ke Bao Yuke Li School of physics Hangzhou Key Laboratory of Quantum MattersHangzhou Normal UniversityHangzhou311121China department of physics Materials Genome Institute and International Center for Quantum and Molecular StructuresShanghai UniversityShanghai200444China Key Laboratory of Quantum Precision Measurement of Zhejiang Province Department of Applied PhysicsZhejiang University of TechnologyHangzhou310023China Songshan Lake Materials Laboratory Dongguan523808China School of Physical Science and Technology Lanzhou UniversityLanzhou730000China

Electron correlation often gives birth to various orders in quantum ***,a strongly correlated kagome antiferromagnet Fe Ge is discovered to undergo a charge density wave transition inside the A-type antiferromagnetic state,providing an opportunity to explore the interplay between charge order and ***,we reported the observation of anisotropic resistivity and Hall effect,along with a topological Hall effect,in the annealed Fe Ge *** the current flows along the abplane,the temperature dependence ofρ_(ab)exhibits a distinct resistivity loop related to a first-order transition at T_(cdw).The applied magnetic fields do not alter T_(cdw)but can induce a spin-flop transition at H_(sf).Consequently,a field-induced large topological Hall effect is observed in the canting antiferromagnetic(CAFM)state below T_(cant),which is possibly attributed to the non-trivial spin texture during the spin-flop ***,as current is parallel to c-axis,both the field-induced transitions inρ_(c)andχ_(c)***,the Hall resistivity in the annealed Fe Ge significantly exhibits a deviation from the linear *** findings provide valuable insight into revealing the interplay among magnetism,charge order and topology in the kagome magnets.

关键词： charge density wave Hall effect transport properties kagome magnet

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