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arXiv 1809.10967cond-mat.quant-gas
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有限粒子数二维玻色气体超流密度普适跳跃的特征

Signatures of a universal jump in the superfluid density in two-dimensional Bose gas with finite number of particles

Krzysztof Gawryluk, Mirosław Brewczyk

摘要:

在经典场近似下,研究了有限个原子的二维弱相互作用均匀玻色气体。通过使用一个大正则系综形式主义,我们表明,这样的系统表现出,除了Berezinskiii-Kosterlitz无(BKT)和热相,中间区域。这一区域的特点是在低动量的电流-电流相关性的衰减和一阶相关性的代数衰减,其指数大于BKT理论预测的临界值。当原子数增加时,在将BKT相从中间区域分离的温度下,超流部分的密度接近Nelson和Kosterlitz在二维超流中发现的密度。

英文摘要:

We study, within the classical fields approximation, a two-dimensional weakly interacting uniform Bose gas of a finite number of atoms. By using a grand canonical ensemble formalism we show that such systems exhibit, in addition to the Berezinskii-Kosterlitz-Thouless (BKT) and thermal phases, the intermediate region. This region is characterized by a decay of current-current correlations at low momenta and by an algebraic decay of the first-order correlations with an exponent being larger than the critical value predicted by the BKT theory. The density of the superfluid fraction at the temperature which separates the BKT phase from the intermediate region approaches the one found by Nelson and Kosterlitz for two-dimensional superfluids while the number of atoms is increased.

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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