论文标题
双层谱机中相关性的有限温度研究
Finite temperature study of correlations in bilayer band-insulator
论文作者
论文摘要
我们对半填充的双层方形晶格的有吸引力的哈伯德模型执行有限的量子量子蒙特卡洛模拟。光学晶格实验的最新进展使我们研究了各种单粒子特性，例如动量分布和双重占用，应在冷原子实验中易于测量。成对对和密度密度相关性已经进行了详细研究，通过有限尺寸的缩放，我们表明在双层谱机模型中没有竞争性的电荷密度波顺序，并且超氟相位是交互作用范围$ \ abs {u}/t = 5-10 $的稳定相。当我们增加了有吸引力的相互作用，一个管理相干性，另一个与分子形成相对应的过程中，我们显示了系统中两个能量尺度的存在。最后，我们绘制了完整的$ t-u $相图，并比较通过平均场分析获得的$ T_C $。我们观察到，对于$ \ abs {u}/t = 6 $，最大$ t_c/t（= 0.27）$发生，大约是单层有吸引力的Hubbard型号报告的$ T_C $的两倍。
We perform the finite-temperature determinant quantum Monte Carlo simulation for the attractive Hubbard model on the half-filled bilayer square lattice. Recent progress on optical lattice experiments lead us to investigate various single-particle properties such as momentum distribution and double occupancies which should be easily measured in cold-atom experiments. The pair-pair and the density-density correlations have been studied in detail, and through finite-size scaling, we show that there is no competing charge density wave order in the bilayer band-insulator model and that the superfluid phase is the stable phase for the interaction range $\abs{U}/t = 5-10$. We show the existence of two energy scales in the system as we increase the attractive interaction, one governing the phase coherence and the other one corresponding to the molecule formation. In the end, we map out the full $T-U$ phase diagram and compare the $T_c$ obtained through the mean-field analysis. We observe that the maximum $T_c/t(= 0.27)$ occurs for $\abs{U}/t = 6$, which is roughly twice the reported $T_c$ of the single-layer attractive Hubbard model.
