The Schrodinger-Poisson-Xalpha (S-P-Xalpha)
model is a "local one particle approximation" of the time dependent
Hartree-Fock equations. It describes the time evolution of electrons
in a quantum model respecting the Pauli principle in an approximate
fashion which yields an effective potential that is the difference
of the nonlocal Coulomb potential and the third root of the local
density. We sketch the formal derivation, existence and uniqueness
analysis of the S-P-Xalpha model with/without an external
potential.
In this paper we deal with numerical simulations based on a time-splitting
spectral method, which was used and studied recently for the nonlinear
Schrodinger (NLS) equation in the semi-classical regime and shows much
better spatial and temporal resolution than finite difference methods.
Extensive numerical results of position density an Winger measures in
1d, 2d, and 3d for the S-P-Xalpha model with/without an
external potential are presented. These results give an insight to
understand the interplay between the nonlocal ("weak") and the local
("strong") nonlinearity.