Berlin 2014 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 40: Interaction with strong or short laser pulses III

A 40.1: Vortrag

Donnerstag, 20. März 2014, 14:00–14:15, BEBEL E34

Time-dependent renormalized natural orbital theory applied to correlated two-electron dynamics — •Martins Brics, Julius Rapp, and Dieter Bauer — Institut für Physik, Universität Rostock, 18051 Rostock

Time-dependent density functional theory (TDDFT) with practicable exchange-correlation functionals fails in capturing highly correlated electron dynamics. In particular, the description of doubly-excited states requires exchange-correlation functionals with memory, which are both unknown and numerically unfavorable. Time-dependent renormalized natural orbital theory (TDRNOT) [1] is a promising approach to circumvent this problem while still overcoming the so-called “exponential wall”. In TDRNOT, the renormalized eigenfunctions of the one-body reduced density matrix, natural orbitals, are the basic variables (instead of the single-particle density, as in TDDFT).

The laser-driven two-electron spin-singlet system is known to be the “worst case” testing ground for TDDFT. Therefore we employ the widely used, numerically exactly solvable, one-dimensional helium model atom (in a laser field) to benchmark the TDRNOT approach. The method is almost as inexpensive numerically as adiabatic TDDFT, but is capable of describing correlated phenomena such as doubly excited states, autoionization, Fano profiles in the photoelectron spectra, and resonant processes such as Rabi oscillations.

[1] M. Brics, D. Bauer, Phys. Rev. A 88, 052514 (2013).