A real-time approach to the optical properties of solids and nano-structures: the time-dependent Bethe-Salpeter equation

TL;DR

This paper introduces a real-time computational method based on the Bethe-Salpeter equation to analyze both linear and nonlinear optical properties of solids and nano-structures, enabling the study of Coulomb correlation effects beyond linear response.

Contribution

A novel real-time approach that extends the Bethe-Salpeter equation to nonlinear regimes for studying optical properties of materials.

Findings

Successfully calculated dielectric constants of bulk h-BN.

Analyzed the effect of strong pulse excitation on optical properties.

Demonstrated numerical stability and flexibility of the method.

Abstract

Many-body effects are known to play a crucial role in the electronic and optical properties of solids and nano-structures. Nevertheless the majority of theoretical and numerical approaches able to capture the influence of Coulomb correlations are restricted to the linear response regime. In this work we introduce a novel approach based on a real-time solution of the electronic dynamics.The proposed approach reduces to the well-known Bethe-Salpeter equation in the linear limit regime and it makes possible, at the same time, to investigate correlation effects in nonlinear phenomena. We show the flexibility and numerical stability of the proposed approach by calculating the dielectric constants and the effect of a strong pulse excitation in bulk {\it h}-BN.