arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0908.4589cond-mat.quant-gascond-mat.str-el
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光晶格上轻费米子-重玻色子混合体的动力学平均场论

Dynamical mean-field theory for light fermion--heavy boson mixtures on optical lattices

M. Iskin, J. K. Freericks

摘要:

我们从理论上分析了由轻费米子和重玻色子组成的费米-玻色混合物,它们被加载到光晶格中(忽略捕获势)。为了描述这样的混合物,我们考虑费米玻色版本的Falicov-Kimball模型的周期晶格。该模型可以精确地映射到零温度下的Fermi-Fermi Falicov-Kimball模型,只要混合物是热力学稳定的。我们利用动力学平均场论研究了Fermi-Bose Falicov-Kimball模型在高温下的演化。我们计算延迟格林函数和自能的谱矩和规则,并使用它们来基准我们的数值计算的准确性,以及通过精确地包括无穷求和或乘积的尾部来降低计算成本。我们展示了如何占有的玻色子,费米子的单粒子多体态密度,动量分布,和平均动能随温度的演变。最后,我们简要讨论了如何在超冷原子系统中实验实现费米-玻色Falicov-Kimball模型。

英文摘要:

We theoretically analyze Fermi-Bose mixtures consisting of light fermions and heavy bosons that are loaded into optical lattices (ignoring the trapping potential). To describe such mixtures, we consider the Fermi-Bose version of the Falicov-Kimball model on a periodic lattice. This model can be exactly mapped onto the spinless Fermi-Fermi Falicov-Kimball model at zero temperature for all parameter space as long as the mixture is thermodynamically stable. We employ dynamical mean-field theory to investigate the evolution of the Fermi-Bose Falicov-Kimball model at higher temperatures. We calculate spectral moment sum rules for the retarded Green's function and self-energy, and use them to benchmark the accuracy of our numerical calculations, as well as to reduce the computational cost by exactly including the tails of infinite summations or products. We show how the occupancy of the bosons, single-particle many-body density of states for the fermions, momentum distribution, and the average kinetic energy evolve with temperature. We end by briefly discussing how to experimentally realize the Fermi-Bose Falicov-Kimball model in ultracold atomic systems.

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