Time-dependent density-functional theory beyond the adiabatic approximation: insights from a two-electron model system
Abstract
Most applications of time-dependent density-functional theory (TDDFT) use the adiabatic local-density approximation (ALDA) for the dynamical exchange-correlation potential Vxc(r,t). An exact (i.e., nonadiabatic) extension of the ground-state LDA into the dynamical regime leads to a Vxc(r,t) with a memory, which causes the electron dynamics to become dissipative. To illustrate and explain this nonadiabatic behavior, this paper studies the dynamics of two interacting electrons on a two-dimensional quantum strip of finite size, comparing TDDFT within and beyond the ALDA with numerical solutions of the two-electron time-dependent Schroedinger equation. It is shown explicitly how dissipation arises through multiple particle-hole excitations, and how the nonadiabatic extension of the ALDA fails for finite systems, but becomes correct in the thermodynamic limit.
Keywords
Cite
@article{arxiv.cond-mat/0610341,
title = {Time-dependent density-functional theory beyond the adiabatic approximation: insights from a two-electron model system},
author = {C. A. Ullrich},
journal= {arXiv preprint arXiv:cond-mat/0610341},
year = {2015}
}
Comments
10 pages, 7 figures