检索结果-南通市图书馆

Topological phase transitions and Majorana zero modes induced by the periodic potential in an antiferromagnetic chain

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2023年第8期75卷 156-162页

作者： K W Shen Q Chen College of Physics and Mechanical&Electrical Engineering Jishou UniversityJishou 416000China School of Computational Science and Electronics Hunan Institute of EngineeringXiangtan 411104China

We investigate the topological properties of an antiferromagnetic(AFM)chain with an on-site periodic potential,considering the intrinsic spin–orbit coupling and an external Zeeman field along with the *** results indicate that Majorana zero modes(MZMs)can be observed by adjusting the strength of the periodic *** have calculated the energy spectrum,the wave-function and transport properties,and all these results support the existence of MZMs in the AFM ***,multiple topological phase transitions occur as the strength of the periodic potential changes,and several regions support MZMs.

关键词： AFM chain Majorana zero modes topological phase transitions periodic potential

Numerical Solution for a Non-Fickian Diffusion in a periodic potential

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Communications in Computational Physics 2013年第2期13卷 502-525页

作者： Adérito Araújo Amal K.Das Cidália Neves Ercília Sousa CMUC Department of MathematicsUniversity of Coimbra3001-454 CoimbraPortugal Department of Physics DalhousieUniversityHalifaxNova Scotia B3H3J5Canada ISCAC Polytechnic Institute of Coimbra3040-316 CoimbraPortugal

Numerical solutions of a non-Fickian diffusion equation belonging to a hyperbolic type are presented in one space *** Brownian particle modelled by this diffusion equation is subjected to a symmetric periodic potential whose spatial shape can be varied by a single *** consider a numerical method which consists of applying Laplace transform in time;we then obtain an elliptic diffusion equation which is discretized using a finite difference *** analyze some aspects of the convergence of the *** results for particle density,flux and mean-square-displacement(covering both inertial and diffusive regimes)are presented.

关键词： Numerical methods Laplace transform telegraph equation periodic potential non-Fickian diffusion

A Simple Model for the Calculation of Diffusion Coefficient in a periodic potential

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Physics 2021年第2期12卷 91-98页

作者： Chunhui Zhang Zhanwu Bai Department of Mathematics and Physics North China Electric Power University Baoding China

Motivated by developing a simple model to calculate the diffusion coefficient in moderate friction region, a simplified model is proposed to deal with the diffusion of Brownian particles in a periodic potential. Where the internal noise is a Gaussian white noise, and the basic cell of the periodic potential is composed of a parabolic potential linked with a harmonic potential. When the particles cross the joint point of the potential, a time coarse-graining scheme is used to obtain a simple analytical expression of the probability distribution. The particles drift and diffuse from the first barrier to the second barrier, the passing probability over the second barrier corresponding to the escape rate becomes decrease serves as the long-jump probability. The theoretical result is confirmed by numerical simulation results. The approach can be extended to color noise case.

关键词： Diffusion Coefficient periodic potential Brownian Motion

Electron-hole hybridization in bilayer graphene

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2020年第2期7卷 248-253页

作者： Siqi Wang Mervin Zhao Changjian Zhang Sui Yang Yuan Wang Kenji Watanabe Takashi Taniguchi James Hone Xiang Zhang NSF Nanoscale Science and Engineering Center (NSEC) University of California Materials Sciences Division Lawrence Berkeley National Laboratory Department of Mechanical Engineering Columbia University National Institute for Materials Science Faculties of Sciences and Engineering University of Hong Kong

Band structure determines the motion of electrons in a solid, giving rise to exotic phenomena when properly engineered. Drawing an analogy between electrons and photons, artificially designed optical lattices indicate the possibility of a similar band modulation effect in graphene systems. Yet due to the fermionic nature of electrons, modulated electronic systems promise far richer categories of behaviors than those found in optical lattices. Here, we uncovered a strong modulation of electronic states in bilayer graphene subject to periodic potentials. We observed for the first time the hybridization of electron and hole sub-bands, resulting in local band gaps at both primary and secondary charge neutrality points. Such hybridization leads to the formation of flat bands, enabling the study of correlated effects in graphene systems. This work may provide a novel way to manipulate electronic states in layered systems, which is important to both fundamental research and application.

关键词： band modulation periodic potential bilayer graphene

Two-dimensional matter-wave solitons and vortices in competing cubic-quintic nonlinear lattices

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Frontiers of physics 2018年第1期13卷 153-161页

作者： Xuzhen Gao Jianhua Zeng State Key Laboratory of Transient Optics and Photonics Xi'an Institute of Optics and Precision Mechanics of CAS Xi'an 710119 China University of Chinese Academy of Sciences Beijing 100084China

The nonlinear lattice - a new and nonlinear class of periodic potentials - was recently introduced to generate various nonlinear localized modes. Several attempts failed to stabilize two-dimensional （2D） solitons against their intrinsic critical collapse in Kerr media. Here, we provide a possibility for supporting 2D matter-wave solitons and vortices in an extended setting - the cubic and quintic model - by introducing another nonlinear lattice whose period is controllable and can be different from its cubic counterpart, to its quintic nonlinearity, therefore making a fully ＂nonlinear quasi-crystal＂. A variational approximation based on Gaussian ansatz is developed for the fundamental solitons and in particular, their stability exactly follows the inverted Vakhitov-Kolokolov stability criterion, whereas the vortex solitons are only studied by means of numerical methods. Stability regions for two types of localized mode -- the fundamental and vortex solitons -- are provided. A noteworthy feature of the localized solutions is that the vortex solitons are stable only when the period of the quintic nonlinear lattice is the same as the cubic one or when the quintic nonlinearity is constant, while the stable fundamental solitons can be created under looser conditions. Our physical setting （cubic-quintic model） is in the framework of the Gross-Pitaevskii equation or nonlinear Schr6dinger equation, the predicted localized modes thus may be implemented in Bose-Einstein condensates and nonlinear optical media with tunable cubic and quintic nonlinearities.

关键词： soliton vortex Bose Einstein condensate periodic potential

A Two-Parameter Continuation Method for Rotating Two-Component Bose-Einstein Condensates in Optical Lattices

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2013年第2期13卷 442-460页

作者： Y.-S.Wang B.-W.Jeng C.-S.Chien Department of Applied Mathematics National Chung Hsing UniversityTaichung 402Taiwan Department of Mathematics Education National Taichung University of EducationTaichung 403Taiwan Department of Computer Science and Information Engineering Ching Yun UniversityJungli 320Taiwan

We study efficient spectral-collocation and continuation methods(SCCM)for rotating two-component Bose-Einstein condensates(BECs)and rotating two-component BECs in optical lattices,where the second kind Chebyshev polynomials are used as the basis functions for the trial function space.A novel two-parameter continuation algorithm is proposed for computing the ground state and first excited state solutions of the governing Gross-Pitaevskii equations(GPEs),where the classical tangent vector is split into two constraint conditions for the bordered linear *** results on rotating two-component BECs and rotating two-component BECs in optical lattices are *** results on the former are consistent with the published numerical results.

关键词： Spectral collocation method second kind Chebyshev polynomials periodic potential bifurcation