arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0909.2166quant-phcond-mat.quant-gas
收藏

与玻色-爱因斯坦凝聚体耦合的冷原子的集体退相干

Collective decoherence of cold atoms coupled to a Bose-Einstein condensate

M. A. Cirone, G. De Chiara, G. M. Palma, A. Recati

备注：
18 pages, 6 figures, two references added
发表信息：
New J. Phys. 11 (2009) 103055
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

我们研究了冷原子（杂质）与简并玻色子量子气体环境相互作用的时间演化。杂质原子不同于环境原子，属于不同的种类。这使得一个可以同时捕获两个独立的捕获势，每个捕获势只对一种原子有效，而对另一种原子透明。当环境是均匀的，杂质被限制在由一组双阱组成的势中时，系统可以用有效的自旋玻色子模型来描述，其中每个位置的左或右阱的占据代表两个（伪）自旋态。本文精确地研究了这类系统的不可逆动力学，即，而不是用马尔可夫主方程单杂质和双杂质的动力学在自旋玻色子系统的标准退相干方面是显著不同的。我们特别展示了：i）相干振荡的出现，i）与自旋玻色子模型的标准相干态不同的超和次退相干态的存在，以及iii）系统中的相干性在长时间内的持久性。我们表明，这种行为是由于这样一个事实，即pseudospins有一个内部的空间结构。我们认为，集体退相干也提示环境的相关长度的信息。在一维构型中，仅通过调节浴的相互作用，就可以更强地改变退相的定性行为。

英文摘要：

We examine the time evolution of cold atoms (impurities) interacting with an environment consisting of a degenerate bosonic quantum gas. The impurity atoms differ from the environment atoms, being of a different species. This allows one to superimpose two independent trapping potentials, each being effective only on one atomic kind, while transparent to the other. When the environment is homogeneous and the impurities are confined in a potential consisting of a set of double wells, the system can be described in terms of an effective spin-boson model, where the occupation of the left or right well of each site represents the two (pseudo)-spin states. The irreversible dynamics of such system is here studied exactly, i.e., not in terms of a Markovian master equation. The dynamics of one and two impurities is remarkably different in respect of the standard decoherence of the spin - boson system. In particular we show: i) the appearance of coherence oscillations, i) the presence of super and sub decoherent states which differ from the standard ones of the spin boson model, and iii) the persistence of coherence in the system at long times. We show that this behaviour is due to the fact that the pseudospins have an internal spatial structure. We argue that collective decoherence also prompts information about the correlation length of the environment. In a one dimensional configuration one can change even stronger the qualitative behaviour of the dephasing just by tuning the interaction of the bath.

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。

↑