Thermodynamics of the three-dimensional Hubbard model: Implications for cooling cold atomic gases in optical lattices
Thermodynamics of the three-dimensional Hubbard model: Implications for cooling cold atomic gases in optical lattices
复制标题
三维哈伯德模型的热力学：对光学晶格中冷原子气体冷却的影响
DOI：
10.1103/physreva.83.023606
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发表时间：
2010
影响因子：
2.9
通讯作者：
V. Scarola
中科院分区：
文献类型：
--
作者：
L. D. Leo;Jean;C. Kollath;A. Georges;V. Scarola
我们对三维费米子Hubbard模型的热力学性质进行了全面的研究，并将其应用于具有光学晶格和囚禁势的冷费米子原子。我们的研究集中在当前实验感兴趣的温度范围内。我们使用了两种理论方法--动态平均场理论和高温序列--并进行了比较基准来界定它们各自的有效范围。特别注意了解该系统的热力学性质对冷却的影响。考虑到非均匀晶格中局域占位的分布函数，我们证明了在绝热演化下，任何可观测到的量(如温度)的变化可以方便地分解为两个不同的贡献。第一个贡献是由于在演化过程中陷阱中原子的重新分布，第二个贡献来自于能观量的本征变化。最后，我们给出了最近提出的一种基于空间熵分离的冷却过程的简化图景，并将该方法应用于一个理想化的模型。
We present a comprehensive study of the thermodynamic properties of the three-dimensional fermionic Hubbard model, with application to cold fermionic atoms subject to an optical lattice and a trapping potential. Our study is focused on the temperature range of current experimental interest. We employ two theoretical methods - dynamical mean-field theory and high-temperature series - and perform comparative benchmarks to delimit their respective range of validity. Special attention is devoted to understand the implications that thermodynamic properties of this system have on cooling. Considering the distribution function of local occupancies in the inhomogeneous lattice, we show that, under adiabatic evolution, the variation of any observable (e.g., temperature) can be conveniently disentangled into two distinct contributions. The first contribution is due to the redistribution of atoms in the trap during the evolution, while the second one comes from the intrinsic change of the observable. Finally, we provide a simplified picture of a recently proposed cooling procedure, based on spatial entropy separation, by applying this method to an idealized model.