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Adiabatic tunneling of Bose–Einstein condensates with modulated atom interaction in a double-well potential 下载免费PDF全文
We study the adiabatic tunneling of Bose–Einstein condensates in a symmetric double-well potential when the interaction strength between the atoms is modulated linearly or in a cosine periodic form. It is shown that the system evolves along a nonlinear eigenstate path. In the case of linear modulation under the adiabatic approximation conditions, the tunneling probability of the condensate atoms to the other potential well is half. However, when the system is periodically scanned in the adiabatic process, we find an interesting phenomenon. A small change in the cycle period can lead to the condensate atoms returning to the right well or tunneling to the left well. The system comes from a linear eigenstate back to a nonlinear one, which is completely different from the linear eigenstate evolution. We explain the results by using the energy level and the phase diagram. 相似文献
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讨论了用遗传算法优化设计普通激光器谐振腔参量的方法.以典型的50 cm长的氦氖(He-Ne)激光器为例,进行了具体计算.结果表明:对于输出相同的激光功率,模拟优化的谐振腔参量与传统局域化设计(非优化)的结果基本一致.通过适当匹配谐振腔参量,仍可提高激光(单模)的输出功率. 相似文献
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Evolution and Collision of Bose—Condensed Gas in One—Dimensional Optical Lattices and a Far—Off Resonant Laser Beam 下载免费PDF全文
Evolution of a Bose-condensed gas in one-dimensional optical lattices is investigated in the presence of a potentialbarrier created by a far-off resonant laser beam. After the magnetic trap and optical lattices are switched off,by using the propagator method, the analytical result of the evolution of the density distribution of the Bose-condensed gas is given. In particular, the collision between the condensate and the potential barrier is shown inthis paper. 相似文献
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光栅衍射实验的误差分析及改进途径 总被引:4,自引:0,他引:4
平行光未能严格垂直入射光栅将形成误差,常用的对称测量法只能消除误差的一阶修正项,仍存在二阶修正项误差。采用测量最小衍射角的方法能有效地消除一阶、二阶修正项的误差,而且能观测到更高级次的衍射条纹,从而减少读数误差,提高实验精度。 相似文献
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Based on the energy functional and variational method, we present a new method to investigate the ground state properties for a weakly interacting Bose-condensed gas in an anisotropic harmonic trap at zero temperature. With this method we are able to find the analytic expression of the ground-state wavefunction and to explore the relevant quantities, such as energy, chemical potential, and the aspect ratio of the velocity distribution. These results agree well with previous ground state numerical solutions of the Gross-Pitaevskii equation given by Dalfovo et al. [Phys. Rev. A 53 (1996) 2477] This new method is simple compared to other methods used to solve numerically the Gross-Pitaevskii equation, and one can obtain analytic and reliable results. 相似文献
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对囚禁在轴对称谐振势阱中的玻色凝聚气体,提出一种新的试探波函数,运用Gross-Pitaevskii(G-P)平均场能量泛函和变分的方法,得到玻色凝聚气体基态和单涡旋态波函数的解析表达式,并计算出凝聚原子的平均能量、原子云轴向和径向尺度比,以及产生单涡旋态的临界角速度等重要物理量与凝聚原子数N之间的关系.其结果与Dalfovo等人直接数值求解G-P方程所得到的结果相一致.
关键词:
玻色凝聚气体
G-P泛函
波函数
谐振势阱 相似文献