论文标题
跨绝缘体到超导体过渡的光谱功能
Spectral functions across an Insulator to Superconductor Transition
论文作者
论文摘要
在最小的2波段模型中，在费米子之间具有吸引人的相互作用，我们将差距计算为单个和两粒子激发，依赖带依赖的光谱函数，使用量子蒙特卡洛（QMC）方法的超流体密度和可压缩性。我们发现，在单粒子光谱函数中明显具有初期配对的签名的费米和玻色绝缘阶段，以及具有三个不同频谱函数的超导状态：（i）两个频段均显示“ BCS”行为，其中最小间隙基因座在下层Fermi表面上发生在封闭的轮廓上； （ii）两个频段均显示“ BEC”行为，其中最小差距在某个点发生； （iii）频带选择性光谱特征，其中一个频段显示“ BCS”，而另一个频段显示“ BEC”行为。在大型相互作用下，我们发现了梯形玻色子的莫特阶段，其中填充是每两个位置的一个玻色子，一半是莫特绝缘子的典型密度约束。
In a minimal 2-band model with attractive interactions between fermions, we calculate the gap to single and two-particle excitations, the band-dependent spectral functions, the superfluid density and compressibility using quantum Monte Carlo (QMC) methods. We find Fermi and Bose insulating phases with signatures of incipient pairing evident in the single-particle spectral functions, and a superconducting state with three different spectral functions: (i) both bands show "BCS" behavior in which the minimum gap locus occurs on a closed contour on the underlying Fermi surface; (ii) both bands show "BEC" behavior in which the minimum gap occurs at a point; and (iii) band selective spectral characteristics, in which one band shows "BCS" while the other shows "BEC" behavior. At large interactions, we find a Mott phase of rung bosons in which the filling is one boson for every two sites, half the typical density constraint for Mott insulators.
