Kiel 2011 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 18: Poster: Theorie/Simulation dichter und stark gekoppelter Plasmen

P 18.3: Poster

Mittwoch, 30. März 2011, 16:30–18:30, Foyer

Time-dependent second Born calculations for model atoms and molecules in external fields — •Karsten Balzer, Sebastian Bauch, and Michael Bonitz — ITAP, Christian-Albrechts-Universität Kiel, Leibnizstr. 15, 24098 Kiel

Nonequilibrium Green function (NEGF) techniques attract more and more attention when correlated quantum many-particle dynamics is under investigation. Thereby, the solution of the Kadanoff-Baym equation (KBE) imposes strong challenges on the numerics—especially when applied to finite systems. This mainly affects the direct propagation of the KBE whereas obtaining equilibrium properties is conceptually relatively simple. Here, we extend previous work [1] to nonequilibrium and propagate the NEGF in the two-time domain. To render calculations possible, an efficient distributed memory algorithm has been developed enabling parallel and well-scalable computation of the NEGF. Also, the use of finite elements in combination with the discrete variable representation greatly simplifies summations over parts of Feynman diagrams. By comparing the density and the dipole moment to time-dependent Hartree-Fock results and the full solution of the time-dependent Schrödinger equation, we demonstrate that the time-dependent second Born approximation carries valuable information about correlation effects in atoms and molecules exposed to external fields [2]. As examples, we present results for helium, hydrogen and lithium hydride modeled in one spatial dimension. [1] K. Balzer, S. Bauch, and M. Bonitz, Phys. Rev. A 81, 022510 (2010). [2] K. Balzer, S. Bauch, and M. Bonitz, Phys. Rev. A 82, 033427 (2010).