共查询到20条相似文献,搜索用时 343 毫秒
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用量子主方程的平均场近似和代数动力学研究玻色-爱因斯坦凝聚体的sympathetic cooling; 用玻色-爱因斯坦凝聚体波函数的运动方程的平均场近似 非线性薛定谔方程研究玻色 爱因斯坦凝聚体的暗孤子和明孤子激发. 相似文献
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本文从G-P平均势场理论出发,探讨了三维球对称非谐势阱中玻色-爱因斯坦凝聚(BEC)的G-P方程;用数值计算方法研究了三维球对称非谐势阱中原子间有相互作用的玻色-爱因斯坦凝聚气体的基态解;分析了非谐振势能项对玻色-爱因斯坦凝聚体的分布、能量和化学势的影响. 相似文献
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文章简要地介绍了玻色-爱因斯坦凝聚体中出现的涡旋和铬原子玻色-爱因斯坦凝聚体的实验研究进展,还介绍了文章作者的一项最新的理论工作。研究指出,由于铬原子磁偶极相互作用的影响,凝聚体中将出现奇特的各向异性的涡旋晶格结构。 相似文献
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本文介绍了北京大学建立的玻色-爱因斯坦凝聚实验平台,实现了玻色-爱因斯坦凝聚(图1),获得了原子数为五十万个,温度为50纳开尔文的玻色凝聚体。在此基础上我们精密测量了玻色-爱因斯坦凝聚的相变温度,还利用玻色-爱因斯坦凝聚实验平台通过马越让那跃迁获得了可控的多量子态玻色爱因斯坦凝聚体。并利用四种方法获得了原子激光(图2),其中有三种方法是国际上第一次使用。另外,我们提出了将玻色一爱因斯坦凝聚转入Magic光晶格阱,实现精度优于10^-17的新型原子钟的设想。 相似文献
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对最近提出的具有纠缠序参量的玻色-爱因斯坦凝聚体作通俗简要的介绍.在这个凝聚体中,不同种原子间形成自旋纠缠的原子对,而系统就在这个纠缠对上发生玻色-爱因斯坦凝聚. 相似文献
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本文从G-P平均势场理论出发,探讨了三维球对称非谐势阱中玻色-爱因斯坦凝聚(BEC)的G-P方程;用数值计算方法研究了三维球对称非谐势阱中原子间有相互作用的玻色-爱因斯坦凝聚气体的基态解;分析了非谐振势能项对玻色-爱因斯坦凝聚体的分布、能量和化学势的影响。 相似文献
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Shyamal Biswas 《Physics letters. A》2008,372(10):1574-1578
Bose-Einstein statistics is derived in the thermodynamic limit when the ratio of system size to thermal de Broglie wavelength goes to infinity. However, according to the experimental setup of Bose-Einstein condensation of harmonically trapped Bose gas of alkali atoms, the ratio near the condensation temperature (To) is 30-50. And, at ultralow temperatures well below To, this ratio becomes comparable to 1. We argue that finite size as well as the ultralow temperature induces corrections to Bose-Einstein statistics. From the corrected statistics we plot condensation fraction versus temperature graph. This theoretical plot satisfies well with the experimental plot [A. Griesmaier et al., Phys. Rev. Lett. 94 (2005) 160401]. 相似文献
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V. I. Yukalov 《Laser Physics》2012,22(7):1145-1168
The peculiarities in the Bose-Einstein condensation of particles and quasiparticles are discussed. The difference between the condensation of conserved and unconserved particles is analyzed. A classification of quasiparticles is given. The emphasis is made on the ability of particles and quasiparticles to condense. Illustrations include: general Bose-condensed atomic systems, such as ensembles of trapped atoms, Bose gases with conserved and unconserved number of atoms, vibrating atoms in double-well lattices, Holstein-Primakoff magnons, Schwinger bosons, slave bosons, and the condensation of singletons and triplons. The basic difference is that the system of particles, whose total number is conserved, can form equilibrium as well as nonequilibrium condensates, while unconserved particles can condense only in a nonequilibrium system subject to external pumping supporting the density of these particles sufficient for their condensation. The examples of such a nonequilibrium condensation of unconserved particles are the Bose-Einstein condensation of excitons, polaritons, and photons. Elementary collective excitations, such as bogolons and phonons, being self-consistently defined, do not condense. Magnons cannot condense in equilibrium systems. Controversies, existing in literature with regard to the Bose-Einstein condensation of some quasiparticles, are explained. Pushing a system out of equilibrium may favor the condensation of unconserved quasiparticles, but suppresses the condensate fraction of conserved particles. 相似文献
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H. Stolz 《Physica A》1977,86(1):111-129
A self-consistent theory of an interacting many-boson system is presented in the framework of the formalism of thermodynamic Green's functions without introducing anomalous propagators referring to the concept of a restricted average or any other symmetry-breaking assumption. Depending on the interaction, the theory comprises both phenomena of Bose-Einstein condensation and of boson pairing without a macroscopic occupation of the zero-momentum single-particle state. The results are discussed with reference to the problem of Bose-Einstein condensation of 4He II and to the phenomenon of exciton condensation and exciton pairing in highly excited semiconductors. 相似文献
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In this paper, we investigate excited characteristic of the weakly interacting quasi-one-dimensional (1D) and quasi-two-dimensional (2D) Bose-Einstein condensation (BEC) in harmonic potential trap. The energy spectrum and the analytical expression of the sound velocity are obtained and analyzed. Compared with 3-Dimensional homogeneous Bose-condensed gas occasion, the sound velocity of 2D Bose-Einstein condensation in harmonic potential trap is smaller. 相似文献
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Observation of Bose-Einstein condensation of molecules 总被引:1,自引:0,他引:1
Zwierlein MW Stan CA Schunck CH Raupach SM Gupta S Hadzibabic Z Ketterle W 《Physical review letters》2003,91(25):250401
We have observed Bose-Einstein condensation of molecules. When a spin mixture of fermionic 6Li atoms was evaporatively cooled in an optical dipole trap near a Feshbach resonance, the atomic gas was converted into 6Li2 molecules. Below 600 nK, a Bose-Einstein condensate of up to 900 000 molecules was identified by the sudden onset of a bimodal density distribution. This condensate realizes the limit of tightly bound fermion pairs in the crossover between BCS superfluidity and Bose-Einstein condensation. 相似文献