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Chinese Physics C 2021年第2期45卷 631-640页

作者：刘鹏牛超张承勇 Department of Physics and Siyuan Laboratory Jinan UniversityGuangzhou 510632China

We study the linear instability of the charged massless scalar perturbation in regularized 4D charged Einstein-Gauss-Bonnet-AdS black holes by exploring their quasinormal modes.We find that the linear instability is triggered by superradiance.The charged massless scalar perturbation becomes more unstable with increasing Gauss-Bonnet coupling constant or black hole charge.Decreasing the AdS radius,on the other hand,will make the charged massless scalar perturbation more stable.The stable region in parameter space(α,Q,Λ)is given.Moreover,we find that the charged massless scalar perturbation is more unstable for larger scalar charge.The modes of multipoles are more stable than that of the monopole.

关键词： black hole quasinormal mode Einstein-Gauss-Bonnet

Instability of regularized 4D charged Einstein-Gauss-Bonnet de-Sitter black holes

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Chinese Physics C 2021年第2期45卷 568-577页

作者：刘鹏牛超张承勇 Department of Physics and Siyuan Laboratory Jinan UniversityGuangzhou 510632China

We studied the instability of regularized 4D charged Einstein-Gauss-Bonnet de-Sitter black holes under charged scalar perturbations.The unstable modes satisfy the superradiant condition,but not all of the modes satisfying the superradiant condition are unstable.The instability occurs when the cosmological constant is small and the black hole charge is not too large.The Gauss-Bonnet coupling constant further destabilizes black holes when both the black hole charge and the cosmological constant are small and further stabilizes black holes when the black hole charge is large.

关键词： black hole Einstein-Gauss-Bonnet instability

Static Dielectric Function and Interaction Potential in Strong Coupling with AdS/CFT

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Communications in Theoretical Physics 2014年第7期61卷 61-65页

作者：刘恋操宣敏刘绘 Department of Physics and Siyuan Laboratory Jinan University

In this paper, we study the static dielectric function and interaction potential in strong coupling limit with AdS/CFT correspondence. The dielectric function is depressed compared with that in weak coupling. The interaction potential then presents a weaker screening characteristics in strong coupling, which indicates a smaller Debye mass compared with weak coupling.

关键词： AdS/CFT QGP finite-temperature field theory

Heat Transport in Double-Bond Linear Chains of Fullerenes

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Chinese Physics Letters 2015年第7期32卷 118-120页

作者：魏亮徐志成郑冬琴张伟钟伟荣 Department of Physics and Siyuan Laboratory Jinan University

Heat transport in one kind of double-bond linear chains of fullerenes （C60＇s） is investigated by the classical nonequilibrium molecular dynamics method. It is found that the negative differential thermal resistance （NDTR） is more likely to occur at larger temperature difference and shorter length. In addition, with the increase of the length, the thermal conductivity of the chains increases, and NDTR region shrinks and vanishes in the end. The temperature profiles reveal that a large temperature jump exists at a high-temperature boundary of the chains when NDTR occurs. These results may be helpful for designing thermal devices where low-dimensional C60 polymers can be used.

关键词： Heat Transport in Double-Bond Linear Chains of Fullerenes

QCD phase diagram at finite isospin chemical potential and temperature in an IR-improved soft-wall AdS/QCD model

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Chinese Physics C 2020年第8期44卷 67-77页

作者：操宣敏刘绘李丹凝欧冠宁 Department of Physics and Siyuan Laboratory Jinan UniversityGuangzhou 510632China

We study the phase transition between the pion condensed phase and normal phase,as well as chiral phase transition in a two flavor(Nf=2)IR-improved soft-wall AdS/QCD model at finite isospin chemical potentialμI and temperature T.By self-consistently solving the equations of motion,we obtain the phase diagram in the plane ofμI and T.The pion condensation appears together with a massless Nambu-Goldstone boson mπ1(Tc,μcI)=0,which is very likely to be a second-order phase transition with mean-field critical exponents in the smallμI region.When T=0,the critical isospin chemical potential approximates to vacuum pion massμcI≈m0.The pion condensed phase exists in an arched area,and the boundary of the chiral crossover intersects the pion condensed phase at a tri-critical point.Qualitatively,the results are in good agreement with previous studies on lattice simulations and model calculations.

关键词： finite isospin chemical potential pion condensation chiral condensation soft-wall AdS/QCD model

Statistical Law of High-Energy Fullerene and Its Derivatives Passing Through Graphene

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Communications in Theoretical Physics 2016年第3期65卷 361-365页

作者：徐志成温家乐钟伟荣魏亮 Department of Physics and Siyuan Laboratory College of Science and EngineeringJinan University

The behavior of graphene bombarded by fullerene(C60 and C70)and its derivatives through using nonequilibrium molecular dynamics method are studied.The microscopic mechanism of passing through graphene is obviously related to the initial structure of destroying carbon-carbon bonds and the strong interaction between the circular region of graphene and the cluster.The probability of passing through graphene depends on the incident velocity of clusters,the species of clusters,the temperature of heat baths,and the defect of graphene.Our results can provide a perspective for further understanding the mechanism of generating nanopores in graphene.The clusters used here may also bring about some potential utilities in tie functionalization of graphene and the production of nanopores.

关键词：衍生物富勒烯石墨统计规律高能量分子动力学方法微观机制强相互作用

Low Thermal Conductivity of Paperclip-Shaped Graphene Superlattice Nanoribbons

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Chinese Physics Letters 2015年第9期32卷 105-107页

作者：陆星钟伟荣 Department of Physics and Siyuan Laboratory College of Science and EngineeringJinan University

We design some graphene superlattice structures with ultra-low thermal conductivity 121 W//mK, which is only 6~ of the straight graphene nanoribbons. The thermal conductivity of graphene superlattice nanoribbons （GSNRs） is investigated by using molecular dynamics simulations. It is reported that the thermal conductivity of graphene superlattiee nanoribbons is significantly lower than that of the straight graphene nanoribbons （GNRs）. Compared with the phonon spectra of straight GNRs, GSNRs have more forbidden bands. The overlap of phonon spectra between two supercells is shrinking.

关键词： Th length Low Thermal Conductivity of Paperclip-Shaped Graphene Superlattice Nanoribbons

One-dimensional mass transport with dynamic external potentials

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Chinese Physics B 2019年第2期28卷 161-166页

作者：张星星郑冬琴钟伟荣 Siyuan Laboratory Department of PhysicsJinan University

Using non-equilibrium molecular dynamics and the Monte Carlo method, we simulated mass transport in a onedimensional channel with dynamic external potentials. This study focuses on the influence of the dynamic external potential field on the mass transport. Traveling wave and standing wave potential fields have been employed as our dynamic potential field. We found that mass transport can be promoted by the traveling wave field when the external potential moves along the direction of the mass current. When the standing wave field is exerted on the channel, the channel is found to work like a switch. The mass current can be "on" or "off" by adjusting the standing wave frequency. The effects of the period number,the amplitude and the velocity of the external potential on the mass transport are also discussed. Our research provides valuable advice for the control o particle transport through one-dimensional channels.

关键词： dynamic external potentials traveling wave standing wave mass transport

Collective transport of Lennard-Jones particles through one-dimensional periodic potentials

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Chinese Physics B 2017年第7期26卷 7-14页

作者：何健辉温家乐陈沛荣郑冬琴钟伟荣 Siyuan Laboratory Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy MaterialsDepartment of Physics Jinan University

The surrounding media in which transport occurs contains various kinds of fields, such as particle potentials and external potentials. One of the important questions is how elements work and how position and momentum are redistributed in the diffusion under these conditions. For enriching Fick＇s law, ordinary non-equilibrium statistical physics can be used to understand the complex process. This study attempts to discuss particle transport in the one-dimensional channel under external potential fields. Two kinds of potentials—the potential well and barrier—which do not change the potential in total, are built during the diffusion process. There are quite distinct phenomena because of the different one-dimensional periodic potentials. By the combination of a Monte Carlo method and molecular dynamics, we meticulously explore why an external potential field impacts transport by the subsection and statistical method. Besides, one piece of evidence of the Maxwell velocity distribution is confirmed under the assumption of local equilibrium. The simple model is based on the key concept that relates the flux to sectional statistics of position and momentum and could be referenced in similar transport problems.

关键词： transport external potential collective diffusion Maxwell velocity distribution

Spin Thermoelectric Effects in a Three-Terminal Double-Dot Interferometer

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Communications in Theoretical Physics 2018年第11期69卷 625-632页

作者：梁峰高本领宋光古宇 Department of Applied Physics Huaiyin Institute of Technology Department of Physics and Siyuan Laboratory Jinan University

We theoretically investigate the thermoelectric properties of a three-terminal double-dot interferometer with Rashba spin-orbit interaction. It is found that with some temperature distributions a thermal spin current can even be produced without the help of magnetic flux and by tuning the spin interference effect in the system, a pure spin or fully spin-polarized current can be driven by temperature differences. For the cases that two of the terminals are held at the same temperature, the charge (spin) thermopower and the charge (spin) figure of merit are defined and calculated in the linear response regime. With some choices of the system parameters the calculated spin and charge thermopowers are of the same order of magnitude and the charge figure of merit can exceed 1.

关键词： thermoelectric effects thermal spin current Rashba spin-orbit interaction,interferometer nonequilibrium Green's function method