论文标题
$ t $ -matrix近似中的静态和动态的伯特 - 盐分方程
Static and Dynamic Bethe-Salpeter Equations in the $T$-Matrix Approximation
论文作者
论文摘要
尽管良好的$ GW $近似近似对应于直接环图的重新启动，并且特别适合弱相关的系统，但$ t $ -matrix的近似值确实是无限级的阶梯图，并且在存在强相关的情况下据称更合适。在这里，当人们考虑$ t $ -matrix Quasiparticle Energies以及基于$ t $ -matrix的内核时，我们首次得出并实现了静态和动态的伯特盐方程。通过计算分子系统的中性激发态来评估静态方案及其扰动动力校正的性能。还报道了与更多常规方案以及其他波功能方法的比较。我们的结果表明，基于$ t $ matrix的形式主义在电子密度保持较低的几个电子系统中表现最好。
While the well-established $GW$ approximation corresponds to a resummation of the direct ring diagrams and is particularly well suited for weakly-correlated systems, the $T$-matrix approximation does sum ladder diagrams up to infinity and is supposedly more appropriate in the presence of strong correlation. Here, we derive and implement, for the first time, the static and dynamic Bethe-Salpeter equations when one considers $T$-matrix quasiparticle energies as well as a $T$-matrix-based kernel. The performance of the static scheme and its perturbative dynamical correction are assessed by computing the neutral excited states of molecular systems. Comparison with more conventional schemes as well as other wave function methods are also reported. Our results suggest that the $T$-matrix-based formalism performs best in few-electron systems where the electron density remains low.
