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arXiv 0904.4110cond-mat.quant-gas
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光晶格中自旋1玻色子的Phase Diagrams

Phase Diagrams for Spin-1 Bosons in an Optical Lattice

Ming-Chiang Chung, Sungkit Yip

摘要:

本文利用平均场论,得到了具有线性和二次塞曼效应的三维光晶格中自旋为1的极性玻色气体在零温和有限温下的相图。根据二次塞曼效应$Q$的大小,可以将相图重新分组为两个不同的参数区域。对于大的$Q$,只有一个一阶相变从磁(NM)阶段的全磁(FM)阶段被发现,而在小的$Q$的情况下,一个一阶相变从磁(PM)阶段的部分(PM)阶段,加上一个二阶相变从PM阶段到FM阶段被获得。如果系统中存在净磁化,则一阶相变导致两相共存和相分离:对于大的$Q$,NM和FM相,以及对于小的$Q$,NM和PM相。还得到了以净磁化强度表示的相图。

英文摘要:

In this paper, the phase diagrams of a polar spin-1 Bose gas in a three-dimensional optical lattice with linear and quadratic Zeeman effects both at zero and finite temperatures are obtained within mean-field theory. The phase diagrams can be regrouped to two different parameter regimes depending on the magnitude of the quadratic Zeeman effect $Q$. For large $Q$, only a first-order phase transition from the nematic (NM) phase to the fully magnetic (FM) phase is found, while in the case of small $Q$, a first-order phase transition from the nematic phase to the partially magnetic (PM) phase, plus a second-order phase transition from the PM phase to the FM phase is obtained. If a net magnetization in the system exists, the first-order phase transition causes a coexistence of two phases and phase separation: for large $Q$, NM and FM phases and for small $Q$, NM and PM phases. The phase diagrams in terms of net magnetization are also obtained.

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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