title: Exact time-dependent density functional theory for impurity models.
abstract: We employ the density matrix renormalization group to construct the exact time-dependent exchange-correlation potential for an impurity model with an applied transport voltage. Even for short-ranged interaction we find an infinitely long-ranged exchange-correlation potential which is built up instantly after switching on the voltage. Our result demonstrates the fundamental difficulties of transport calculations based on time-dependent density functional theory. While formally the approach works, important information can be missing in the ground-state functionals and may be hidden in the usually unknown non-equilibrium functionals.
authors.affiliation: Institute of Nanotechnology, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Schmitteckert
authors.forename: Michael
authors.initials: M
authors.lastname: Dzierzawa
authors.forename: Peter
authors.initials: P
authors.lastname: Schwab