Accurate high-harmonic spectra from time-dependent two-particle reduced density matrix theory

TL;DR

This paper introduces a three-dimensional implementation of the time-dependent two-particle reduced density matrix method for many-electron atoms, providing accurate high-harmonic spectra and capturing electron-correlation effects efficiently.

Contribution

The paper presents a novel 3D implementation of TD-2RDM for atoms, enabling accurate non-linear response calculations with reduced computational complexity.

Findings

TD-2RDM accurately reproduces harmonic spectra of beryllium and neon.

The method effectively captures electron-correlation effects in atomic responses.

Benchmarking shows strong agreement with MCTDHF results.

Abstract

The accurate description of the non-linear response of many-electron systems to strong-laser fields remains a major challenge. Methods that bypass the unfavorable exponential scaling with particle number are required to address larger systems. In this paper we present a fully three-dimensional implementation of the time-dependent two-particle reduced density matrix (TD-2RDM) method for many-electron atoms. We benchmark this approach by a comparison with multi-configurational time-dependent Hartree-Fock (MCTDHF) results for the harmonic spectra of beryllium and neon. We show that the TD-2RDM is very well-suited to describe the non-linear atomic response and to reveal the influence of electron-correlation effects.