Nonequilibrium Green functions in Time-Dependent Density
Functional Theory

Robert van Leeuwen (Groningen)

We give an overview of the underlying concepts of time-dependent
current-density functional theory. The basic one-to-one 
mappings between (current) densities and (vector) potentials
are discussed. Some fundamental difficulties associated with
the time-dependent action principle are discussed and we show how
these difficulties can be resolved by use of a nonequilibrium
Green function formalism. We further demonstrate how the
formalism can be used to derive explicit equations for
the exchange-correlation (vector) potentials for the 
time-dependent Kohn-Sham equations.

References:
R.van Leeuwen, Int.J.Mod.Phys.B15, 1969 (2001)
R.van Leeuwen, Phys.Rev.Lett.80, 1280 (1998)
R.van Leeuwen, Phys.Rev.Lett.76, 3610 (1996)