共查询到19条相似文献,搜索用时 203 毫秒
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李玉山 《原子与分子物理学报》2014,31(4):683-686
基于Thomas-Fermi半经典近似研究了谐振子势阱约束下任意维理想玻色气体的玻色-爱因斯坦凝聚(BEC).导出了玻色气体的BEC转变温度、基态粒子占据比例、内能和热容量等物理量的解析表达式,讨论了空间维度和谐振子势阱的影响.以二维和三维玻色系统为例,数值计算了上述热力学量,并与解析结果进行了对比,二者获得了较好的吻合. 相似文献
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李玉山 《原子与分子物理学报》2015,32(6)
基于Thomas-Fermi半经典近似方法研究了谐振子势阱约束下任意维理想玻色气体的玻色-爱因斯坦凝聚(BEC).导出了玻色气体的BEC转变温度、基态粒子占据比例、内能和热容量等物理量的解析表达式,讨论了空间维度和谐振子势阱的影响.以二维和三维玻色系统为例,数值计算了上述热力学量,并与解析结果进行了对比,二者获得了较好的吻合. 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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采用半经典近似方法,研究简谐势阱中二维理想带电玻色气体的磁性质.推导出了该体系的热力学势、相变温度、内能、比热、磁场强度和磁化率随外加磁场的变化关系,进而分析了约束势阱对理想带电玻色气体热力学性质的影响. 相似文献
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研究了玻色-费米超流混合体系中的相互作用调制隧穿动力学特性,其中玻色子位于对称双势阱中,费米子位于对称双势阱中心的简谐势阱中.采用双模近似方法得到描述双势阱玻色-爱因斯坦凝聚的动力学特性方程组,并将其与简谐势阱中分子玻色-爱因斯坦凝聚的Gross-Pitaevskii方程进行耦合.通过对不同参数下玻色-费米混合体系中的隧穿现象进行数值研究,发现简谐势阱中费米子与双势阱中玻色子的相互作用使双势阱玻色-爱因斯坦凝聚的隧穿动力学特性更加丰富.不但驱使双势阱中玻色-爱因斯坦凝聚从类约瑟夫森振荡转变为宏观量子自囚禁,而且宏观量子自囚禁表现为三种不同的形式:相位与时间呈负相关并随时间单调减小的自囚禁、相位随时间演化有界的自囚禁以及相位与时间呈正相关并随时间单调增大的自囚禁. 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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求出了γ维空间中理想玻色气体的态密度,采用Thomas-Fermi近似,导出了γ维广义幂律势阱中粒子数密度的空间分布.在此基础上,求出了原子激射器的空间有效增益范围(即γ维势阱中玻色-爱因斯坦凝聚的空间有效范围),并对其产生影响的相关因素进行了讨论. 相似文献
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Hideo Hasegawa 《Physica A》2010,389(12):2358-2499
Recently it has been shown by the present author [H. Hasegawa, Phys. Rev. E 80 (2009) 011126] that the interpolation approximation (IA) to the generalized Bose-Einstein and Fermi-Dirac distributions yields good results in agreement with the exact ones within the O(q−1) and in high- and low-temperature limits, where (q−1) expresses the nonextensivity: the case of q=1 corresponding to the conventional quantal distributions. This paper reports applications of the IA to four nonextensive quantum subjects: (i) the black-body radiation, (ii) the Bose-Einstein condensation, (iii) the BCS superconductivity and (iv) itinerant-electron (metallic) ferromagnetism. Effects of the nonextensivity on physical quantities in these nonextensive quantum systems have been investigated. Comparisons between the calculated results and available observed data are made for the subjects (ii) and (iii). It has been pointed out that the factorization approximation (FA) which has been so far applied to many nonextensive systems, overestimates the nonextensivity and that it leads to inappropriate results for fermion systems like the subjects (iii) and (iv). 相似文献
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《Physics letters. A》2006,359(5):357-358
Analytical expressions for Bose–Einstein condensation of an ideal Bose gas analyzed within the strictures of nonextensive, generalized thermostatistics are here obtained. 相似文献
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We study a one-dimensional gas of Bosons interacting through Neumann hard cores of diametera. Attractive boundary conditions are imposed on the system, so that whena = 0 the model exhibits Bose-Einstein condensation and singular thermodynamic functions. In the presence of a hard core (a>0), the free energy density retains its singularity, but Bose-Einstein condensation does not persist, even in the generalized sense. 相似文献
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利用推广 Gross- Pitaevskii方程 ,分别研究了 (2 +1 )维时空和 3维空间的 Bose- Einstein凝聚体中涡旋的拓扑结构 .这一推广的方程能够被用于非均匀并且高度非线形的 Bose- Einstein凝聚系统 .利用Φ映射拓扑流理论 ,给出了基于序参数的涡旋速度场,以及该速度场的拓扑结构 .最后 ,仔细地探讨了这两种 Bose- Einstein系统中涡旋的各种分支条件.We studied the topological structure of vortex in the Bose-Einstein condensation with a generalized Gross-Pitaevskii equation in (2+1)-dimensional space-time and 3-dimensional space, respectively. Such equation can be used in discussing Bose-Einstein condensates in heterogeneous and highly nonlinear systems. An explicit expression for the vortex velocity field as a function of the order parameter field is derived in terms of the Φ -mapping theory, and the topological structure of ... 相似文献
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Lavagno A Swamy PN 《Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics》2000,61(2):1218-1226
We show that a natural realization of the thermostatistics of q bosons can be built on the formalism of q calculus, and that the entire structure of thermodynamics is preserved if we use an appropriate Jackson derivative in place of the ordinary thermodynamics derivative. This framework allows us to obtain a generalized q boson entropy which depends on the q basic number. We study the ideal q boson gas in the thermodynamic limit which is shown to exhibit Bose-Einstein condensation with a higher critical temperature and a discontinuous specific heat. 相似文献
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The equation of state is discussed for a system of degenerate fermions. The formation of bound states is allowed for; the latter may exhibit the Bose-Einstein condensation. A complex representation is given which includes bound and scattering two-particle states as well. Different (generalized) representations in terms of scattering quantities are given for the continuum contribution. 相似文献
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We derive generalized two-superfluid continuity equations for the BEC-BCS crossover in the presence of a Feshbach resonance at T=0. In addition, we calculate the velocity of sound throughout both BCS and Bose-Einstein condensation (BEC) regimes. 相似文献
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By considering generalized logarithm and exponential functions used in nonextensive statistics, the four usual algebraic operators: addition, subtraction, product and division, are generalized. The properties of the generalized operators are investigated. Some standard properties are preserved, e.g. associativity, commutativity and existence of neutral elements. On the contrary, the distributivity law and the opposite element are no more universal within the generalized algebra. 相似文献