Systematic construction of density functionals based on matrix product state computations

MICHAEL LUBASCH; JOHANNA I FUKS; IGNACIO CIRAC; ANGEL RUBIO

NEW JOURNAL OF PHYSICS

IOP PUBLISHING LTD

Año: 2016 vol. 18

1367-2630

We propose a systematic procedure for the approximation of density functionals in density functionaltheory that consists of two parts. First, for the efficient approximation of a general density functional,we introduce an efficient ansatz whose non-locality can be increased systematically. Second, wepresent a fitting strategy that is based on systematically increasing a reasonably chosen set of trainingdensities. We investigate our procedure in the context of strongly correlated fermions on a one-dimensional lattice in which we compute accurate training densities with the help of matrix productstates. Focusing on the exchange-correlation energy, we demonstrate how an efficient approximationcan be found that includes and systematically improves beyond the local density approximation.Importantly, this systematic improvement is shown for target densities that are quite different fromthe training densities.