Berlin 2015 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 91: Frontiers of electronic structure theory: Many-body effects, methods
HL 91.3: Talk
Thursday, March 19, 2015, 15:45–16:00, MA 004
Exact functionals for a lattice model — •Tanja Dimitrov1, Heiko Appel1,3, and Angel Rubio1,2,3 — 1Fritz-Haber-Institut der MPG, Berlin — 2Nano-bio Spectroscopy Group/ETSF Scientific Development Centre, Universidad del Pais Vasco UPV/EHU, San Sebastian — 3MPI for the Structure and Dynamics of Matter, Hamburg
Standard local exchange-correlation and semi-local functionals in ground-state density functional
theory are known for their shortcomings in describing correct charge transfer,
dissociation energies of molecular ions, and barriers
of chemical reactions [1,2]. To understand the failures of approximate functionals, to gain insight into the
behavior of the exact functional, and to devise new approximations, we investigate the
exact solution of the many-body Schrödinger equation in Fock space for a lattice model
with a softened Coulomb interaction term.
Using quadratic optimization with quadratic constraints,
or alternatively exact diagonalization, we explicitely construct the exact
density-to-potential and density-to-wave-function map. We discuss the behavior of functionals in
the low-density limit.
[1] A. J. Cohen et al. Science 321, 792 (2008).
[2] P. Mori-Sanchez et al., Phys. Rev. Lett. 100, 146401 (2008).