Harsha Gaurav, Henderson Thomas M, Scuseria Gustavo E
Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA.
J Chem Phys. 2020 Sep 28;153(12):124115. doi: 10.1063/5.0022702.
We present a wave function representation for the canonical ensemble thermal density matrix by projecting the thermofield double state against the desired number of particles. The resulting canonical thermal state obeys an imaginary-time evolution equation. Starting with the mean-field approximation, where the canonical thermal state becomes an antisymmetrized geminal power (AGP) wave function, we explore two different schemes to add correlation: by number-projecting a correlated grand-canonical thermal state and by adding correlation to the number-projected mean-field state. As benchmark examples, we use number-projected configuration interaction and an AGP-based perturbation theory to study the hydrogen molecule in a minimal basis and the six-site Hubbard model.
我们通过将热场双重态投影到所需的粒子数上，给出了正则系综热密度矩阵的波函数表示。由此得到的正则热态服从一个虚时演化方程。从平均场近似出发，在该近似下正则热态成为反对称双粒子幂（AGP）波函数，我们探索了两种不同的添加关联的方案：通过对关联的巨正则热态进行数投影，以及通过对已进行数投影的平均场态添加关联。作为基准示例，我们使用数投影组态相互作用和基于AGP的微扰理论来研究最小基组下的氢分子和六格点哈伯德模型。
