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arXiv 1704.07623cond-mat.quant-gasquant-ph
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玻色极化子是量子布朗运动的一个例子

Bose polaron as an instance of quantum Brownian motion

Aniello Lampo, Soon Hoe Lim, Miguel Ángel García-March, Maciej Lewenstein

摘要:

在量子布朗运动模型的框架下,研究了玻色-爱因斯坦凝聚体中量子杂质的动力学行为。我们推导出一个广义朗之万方程的位置的杂质。朗之万方程是一个包含记忆核的积分微分方程,由色噪声驱动。这些结果从考虑环境中所给出的量子气体的自由度,从而取决于它的参数,例如玻色子之间的相互作用强度,温度等,我们研究的作用的内存上的动态杂质。当杂质未被捕获时,我们发现它在长时间内表现出超扩散行为。我们发现,在进化过程中,环境和杂质之间的能量回流发生。当粒子被捕获时,我们计算位置和动量的方差,以确定它们与海森堡极限的比较。本文的一个重要结果是发现了囚禁杂质在长时间内的位置压缩。我们确定我们的模型的有效性和参数,这些影响可以在现实的实验中观察到的制度。

英文摘要:

We study the dynamics of a quantum impurity immersed in a Bose-Einstein condensate as an open quantum system in the framework of the quantum Brownian motion model. We derive a generalized Langevin equation for the position of the impurity. The Langevin equation is an integrodifferential equation that contains a memory kernel and is driven by a colored noise. These result from considering the environment as given by the degrees of freedom of the quantum gas, and thus depend on its parameters, e.g. interaction strength between the bosons, temperature, etc. We study the role of the memory on the dynamics of the impurity. When the impurity is untrapped, we find that it exhibits a super-diffusive behavior at long times. We find that back-flow in energy between the environment and the impurity occurs during evolution. When the particle is trapped, we calculate the variance of the position and momentum to determine how they compare with the Heisenberg limit. One important result of this paper is that we find position squeezing for the trapped impurity at long times. We determine the regime of validity of our model and the parameters in which these effects can be observed in realistic experiments.

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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