Time-Dependent Two-Particle Reduced Density Matrix Theory: Application to High-Harmonic Generation

30th International Conference on Photonic, Electronic, and Atomic Collisions

Lackner, Fabian^1 ; Bezinová, Iva^1 ; Sato, Takeshi^2,3 ; Ishikawa, Kenichi L.^2,3 ; Burgdörfer, Joachim^1

Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10/136, EU, Vienna

1040, Austria^1

Photon Science Center, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo

113-8656, Japan^2

Department of Nuclear Engineering and Management, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo

113-8656, Japan^3

关键词: Accurate calculations;    Closure approximation;    High harmonic generation;    Ionization dynamics;    Reduced density-matrix theories;    Reduced-density matrix;    Time dependent density functional theory;    Time-dependent hartree-fock;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/875/2/012011/pdf
DOI  :  10.1088/1742-6596/875/2/012011

来源: IOP

【 摘 要 】

We simulate the electronic response of atoms to strong laser pulses by propagating the time-dependent two-particle reduced density matrix (TD-2RDM). The propagation of the 2RDM requires carefully designed closure approximations to decouple the equation of motion for the 2RDM from the higher members of the Bogoliubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy. Recent improvements in the closure approximation allow the accurate calculation of high-harmonic spectra from beryllium and neon targets where mean field theories such as time-dependent Hartree-Fock and time-dependent density functional theory show sizable discrepancies to multiconfigurational time-dependent Hartree-Fock (MCTDHF) reference calculations. We trace these differences back to the ionization dynamics. We find that the accurate description of the ionization dynamics is the key to achieve agreement with high-harmonic spectra from MCTDHF.