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arXiv 1409.7659cond-mat.quant-gas
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振幅调制抛物光晶格中非相互作用超冷玻色子的单粒子分析

Single-particle Analysis of Non-interacting Ultracold Bosons in Amplitude Modulated Parabolic Optical Lattice

Tomotake Yamakoshi, Shinichi Watanabe

摘要:

在抛物阱和光晶格的联合势场中的超冷原子被认为是一种很有前途的对物质波包进行相干操纵的工具。最近的奥胡斯实验[P.L. Pedersen等人,物理学修订版A。88,023620(2013)]通过将光晶格的振幅调制应用于$^{87}$ Rb的玻色-爱因斯坦凝聚体(BEC)来产生波包。本文用单粒子分析的方法对实验产生的波包及其随时间的演化作了理论解释。我们专注于一维非相互作用玻色子系统作为一个基本的出发点,精确的量子分析和进一步调查类似的实验。我们发现,一个简单的Rabi振荡模型可以很好地描述带间跃迁的波包产生,而一阶微扰理论证明是不够的,即最近的实验已经达到了高阶耦合的境界。作为一个自然的扩展,我们证明了增强的波包生产的两步拉比振荡方法,使用单频或双频。我们借助严格的量子时间传播以及汉堡实验早期利用的半经典理论[J. Heinze et al.,PRL 107,135303(2011)]。自由演化过程中波包的复杂反射和分裂很大程度上是这两种效应交织的结果。

英文摘要:

Ultracold atoms in the combined potential of a parabolic trap and an optical lattice is considered a promising tool for coherent manipulation of matter wave packets. The recent Aarhus experiment[P. L. Pedersen et al., Phys. Rev. A. 88, 023620 (2013)] produced wave packets by applying the optical lattice's amplitude modulation to a Bose-Einstein condensate (BEC) of $^{87}$Rb. The present paper renders a theoretical account with single-particle analysis of this experimental production of the wave packets and their subsequent time-evolution. We focus on the one-dimensional non-interacting bosonic system as a fundamental starting point for accurate quantum analysis and for further investigation of similar experiments. We show that a simple Rabi-oscillation model gives a good description of the wave packet production in terms of the inter-band transition while the first-order perturbation theory proves inadequate, that is the recent experiment already reached the realm of high-order couplings. As a natural extension, we demonstrate enhancement of the wave packet production by the two-step Rabi-oscillation method using either single frequency or dual frequencies. We assess the high-order Bragg reflection and Landau-Zener transition at a band gap with the aid of rigorous quantum time-propagation as well as the semi-classical theory exploited earlier by the Hamburg experiment [J. Heinze et al., PRL 107, 135303(2011)]. Complicated reflections and splittings of the wave packet during free evolution may be largely attributed to the intertwining of these two effects.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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