Time-dependent density-functional and reduced density-matrix methods for few electrons: Exact versus adiabatic approximations

NICOLE HELBIG; JOHANNA I FUKS; ILYA V. TOKATLY; HEIKO APPEL; E.K.U. GROSS; ANGEL RUBIO

JOURNAL OF CHEMICAL PHYSICS

AMER INST PHYSICS

Lugar: New York; Año: 2011 vol. 391

0021-9606

To address the impact of electron correlations in the linear and non-linear response regimes of interactingmany-electron systems exposed to time-dependent external fields, we study one-dimensional (1D)systems where the interacting problem is solved exactly by exploiting the mapping of the 1D N-electronproblem onto an N-dimensional single electron problem. We analyze the performance of the recentlyderived 1D local density approximation as well as the exact-exchange orbital functional for thosesystems. We show that the interaction with an external resonant laser field shows Rabi oscillations whichare detuned due to the lack of memory in adiabatic approximations. To investigate situations where staticcorrelations play a role, we consider the time-evolution of the natural occupation numbers associated tothe reduced one-body density matrix. Those studies shed light on the non-locality and time-dependenceof the exchange and correlation functionals in time-dependent density and density-matrix functionaltheories