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Analytical Results of Eigenstates and Eigenenergies by Mixing Models of Five Bosonic Modes

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Chinese Physics Letters 2004年第6期21卷 1003-1005页

作者： LIWei-Bin ZHANZhi-Ming XIEXiao-Tao LUOJin-Ming WUXuan DepartmentofPhysics HuazhongUniversityofScienceandTechnologyWuhan430074 StateKeyLaboratoryofLaserTechnology HuazhongUniversityofScienceandTechnologyWuhan430074

The analytical expressions of eigenstates and eigenenergies are demonstrated using a parameter λ without the assumption of Bethe ansatz for two kinds of five-mode mixing models. It is found that the parameter can be determined by the roots of a simple polynomial. We also illustrate the exact analytical expressions of eigenstates and energies without any unknown parameter.

关键词： quantum gases liquids and solids Mathematical physics Statistical physics and nonlinear systems

Stability of Bright Solitons in Bose-Einstein Condensates

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Chinese Physics Letters 2004年第10期21卷 1881-1883页

作者：俞慧友颜家壬谢琼涛 DepartmentofPhysics HunanNormalUniversityChangsha410081

We investigate the stability of bright solitons in Bose-Einstein condensates by including a feeding term and a loss one in the Gross-Pitaevskii equation. Based on the direct approach of perturbation theory for the nonlinear Schrodinger equation, we give the explicit dependence of the height and other related quantities of bright solitons on the feeding and loss term. It is found that the three-body recombination loss plays a crucial role in stabilizing bright solitons.

关键词： quantum gases liquids and solids quantum information and quantum mechanics

Ground State Density Distribution of Bose-Fermi Mixture in a One-Dimensional Harmonic Trap

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Chinese Physics Letters 2011年第1期28卷 16-19页

作者： HAO Ya- Jiang Department of Physics University of Science and Technology Beijing Beijing 100083

By the density-functional calculation we investigate the ground-state properties of Bose-Fermi mixture confined in one-dimensional harmonic traps. The homogeneous mixture of bosons and polarized fermions with contact interaction can be exactly solved by the Bethe-ansatz method. After giving the exact formula of ground state en- ergy density, we employ the local-density approximation to determine the density distribution of each component. It is shown that with the increase in interaction, the total density distribution evolves to Fermi-like distribution and the system exhibits phase separation between finite. While in the infinite interaction limit both distributions and phase separation disappears. two components when the interaction is strong enough but bosons and fermions display the completely same Fermi-like

关键词： quantum gases liquids and solids Mathematical physics Statistical physics and nonlinear systems

Analysis of Runaway Evaporation and Bose-Einstein Condensation by Time-of-Flight Absorption Imaging

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Chinese Physics Letters 2004年第11期21卷 2105-2108页

作者：陈帅周小计杨帆夏林孙亚亚王义道陈徐宗 KeyLaboratoryforquantumInformationandMeasurementsofMinistryofEducation PekingUniversityBeijing100871

The achievement of Bose--Einstein condensation (BEC) in our experiment is reported. The process of BEC formation is observed by detecting the image after free expansion, in which the effectiveness of runaway evaporative cooling is shown by measuring the optical density of the atom cloud. About 2×105 87Rb atoms in the |F=2, mF=2> state are condensed into the condensate. The ratio of axial-to-radial size of the condensate released from the magnetic trap is investigated in theory and experiment.

关键词： quantum gases liquids and solids Atomic and molecular physics Optics quantum optics and lasers

Possible Origin of Magnetic Fields in Very Dense Stars

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Chinese Physics Letters 2004年第11期21卷 2117-2119页

作者： A.PérezMartínez H.PérezRojas H.J.MosqueraCuesta GrupodeFisicaTeorica ICIMAFCalleENo.309VedadoLaHabanaCuba CentroBrasileirodePesquisasFísicas LaboratóriodeCosmologiaeFísicaExperimentaldeAltasEnergiasRuaDr.XavierSigaud150Cep22290-180.UrcaRiodeJaneiroRJBrazil

We discuss the bosonization of a relativistic very dense Fermi gas in a magnetic field and the consequent Bose-Einstein condensation of the resulting relativistic vector gas of charged particles. The model may be applied to paired spin-up electrons. We show that such systems may maintain self-consistently magnetic fields of order 10(10) - 10(13) G. That pairing could be the origin of large magnetic fields in some white dwarfs and neutron stars. For fields large enough (similar to10(13) for white dwarfs), the system becomes unstable and collapses.

关键词： quantum gases liquids and solids Gravitation and cosmology Statistical physics and nonlinear systems Astrophysics and astroparticles

Exact Eigenstates for a Class of Models Describing Multiphoton Processes in the Presence of Six Bosonic Modes

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Chinese Physics Letters 2004年第6期21卷 983-986页

作者： ZHANZhi-Ming LIWei-Bin LIJia-Hua YANGWen-Xing CHENAi-Xi StateKeyLaboratoryofLaserTechnology HuazhongUniversityofScienceandTechnologyWuhan430074 DepartmentofPhysics HuazhongUniversityofScienceandTechnologyWuhan430074 CentreforColdAtomPhysics ChineseAcademyofSciencesWuhan430071

We present an efficient approach to study the spectra and eigenstates for the model describing six multiphoton processes in the presence of bosonic modes without using the assumption of the Bethe ansatz. The exact analytical results of all the eigenstates and eigenvalues are in terms of a parameter λ for a class of models describing the six-mode multiphoton processes. The parameter is determined by the roots of a polynomial and is solvable analytically or numerically.

关键词： quantum gases liquids and solids Mathematical physics Optics quantum optics and lasers quantum information and quantum mechanics Statistical physics and nonlinear systems

Evolution and Collision of Bose-Condensed gases in an Infinitely Deep Square Well

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Chinese Physics Letters 2004年第2期21卷 239-242页

作者：徐志君刘淑娟黄琳武强熊宏伟 DepartmentofAppliedPhysics ZhejiangUniversityofTechnologyHangzhou310032

The evolution and collision of Bose-condensed gases in one-dimensional optical lattices are investigated in the presence of an infinitely deep square well crested by two far-off resonant laser beams. The two far off resonant laser beams are superimposed on the combined potential consisting of a magnetic trap and one-dimensional optical lattices. After the combined potential is switched off, the analytical result of the evolution of the density distribution of the Bose-condensed gas is given by using the propagator method. The collisions between the condensate and the infinitely deep square well are shown in the present work.

关键词： quantum gases liquids and solids Optics quantum optics and lasers Statistical physics and nonlinear systems

Effects of the Scattering Length on the Yrast Spectrum for a Two-Component Bose-Einstein Condensates

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Chinese Physics Letters 2004年第12期21卷 2351-2354页

作者：于洋罗斌刘琨周小计陈徐宗 SchoolofElectronicEngineeringandComputerScience PekingUniversityBeijing100871//KeyLaboratoryforQuantumInformationandMeasurementsofMinistryofEducationPekingUniversityBeijing100871

We study the energy eigenvalue and the yrast states for a harmonically two-component weak-interacting Bose--Einstein condensate (BEC) when the intra-species and interspecies scattering length are different. The energy shift for different energy eigenvalues related to intra- and interspecies scattering lengths is calculated with the perturbation method. The actual yrast spectrum is more complicated than that when intra-species and interspecies scattering length are equal. The degenerated features disappear and so do the perfect symmetric features.

关键词： quantum gases liquids and solids Atomic and molecular physics Statistical physics and nonlinear systems

Topological Aspects in an Interacting Mixture of a Charged and a Neutral Superfluid in Neutron Stars

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Chinese Physics Letters 2009年第7期26卷 392-396页

作者：任继荣郭恒张欣会李然 Institute of TheoreticaJ Physics Lanzhou University Lanzhou 730000

By making use of the decomposition of U（1） gauge potential theory and the C-mapping method we discuss a mixture of interacting neutral and charged Bose condensates, which is supposed to be realized in the interior of neutron stars in the form of a coexistent neutron superfluid and protonie superconductor. We propose that this system possesses vortex line knotted solitons and the topological charges of vortex lines are characterized by the winding numbers of the C-mapping. Furthermore the spatial bifurcation of vortices is also discussed.

关键词： quantum gases liquids and solids Astrophysics and astroparticles