论文标题
累积格林功能的实时耦合群集方法
Real-time coupled-cluster approach for the cumulant Green's function
论文作者
论文摘要
多体扰动理论中格林的功能方法为治疗激发态中的电子相关性提供了一个通用框架。在这里，我们根据我们先前研究的扩展，基于运动方法的耦合群集方程来研究单电子绿色功能的累积形式。该方法以对一组耦合的一阶，非线性微分方程的求解为累积剂产生非扰动表达。因此，该方法将非线性校正添加到自我能量中线性的传统累积方法中。该方法应用于核心孔绿色的功能，并用于许多小分子系统。对于这些系统，我们发现非线性贡献导致了准粒子特性（例如核心水平结合能，以及与光发射光谱中观察到的非弹性损失相对应的卫星）的显着改善。
Green's function methods within many-body perturbation theory provide a general framework for treating electronic correlations in excited states. Here we investigate the cumulant form of the one-electron Green's function based on the coupled-cluster equation of motion approach in an extension of our previous study. The approach yields a non-perturbative expression for the cumulant in terms of the solution to a set of coupled first order, non-linear differential equations. The method thereby adds non-linear corrections to traditional cumulant methods linear in the self energy. The approach is applied to the core-hole Green's function and illustrated for a number of small molecular systems. For these systems we find that the non-linear contributions lead to significant improvements both for quasiparticle properties such as core-level binding energies, as well as the satellites corresponding to inelastic losses observed in photoemission spectra.
