近实频率轴上的动力学平均场论方程
Dynamical Mean Field Theory equations on nearly real frequency axis
摘要：
在近似实频率下，求解了半填充哈伯德模型的动力学平均场论（DMFT）的迭代微扰理论（IPT）方程，研究了有限温度下金属-绝缘体相变（MIT）的性质.这种方法避免了与臭名昭著的Padé解析延拓相关的不稳定性，并揭示了在有限温度下MIT的精细结构，这{ \em不能被捕获}通过传统的方法求解松原频率上的DMFT方程。我们的方法表明，在有限的温度下，在准粒子（近藤）峰的高度在$U_c$的临界值突然下降，到一个非零，但小的凸块，逐渐抑制，因为一个移动到{ \em坏}绝缘体制度更深。与Vollhardt等人[J. Phys. Soc. Jpn. { \bf 74}（2005）136]，下至半带宽的$T=0.01$，我们发现没有$T^*$将不良绝缘体与真正的莫特绝缘体分开。
英文摘要：
The Iterated Perturbation Theory (IPT) equations of the Dynamical Mean Field Theory (DMFT) for the half-filled Hubbard model, are solved on nearly real frequencies at various values of the Hubbard parameters $U$, to investigate the nature of metal-insulator transition (MIT) at finite temperatures. This method avoids the instabilities associated with the infamous Padé analytic continuation and reveals fine structures across the MIT at finite temperatures, which {\em can not be captured} by conventional methods for solving DMFT equations on Matsubara frequencies. Our method suggests that at finite temperatures, there is an abrupt decrease in the height of the quasi-particle (Kondo) peak at a critical value of $U_c$, to a non-zero but small bump which gradually suppresses as one moves deeper into the {\em bad} insulator regime. In contrast to Vollhardt and coworkers [J. Phys. Soc. Jpn. {\bf 74} (2005) 136], down to $T=0.01$ of the half-bandwidth we find no $T^*$ separating bad insulator from a true Mott insulator.
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