Exact thermal density functional theory for a model system: Correlation components and accuracy of the zero-temperature exchange-correlation approximation
Strongly Correlated Electrons
2016-06-29 v2 Materials Science
Abstract
Thermal density functional theory calculations often use the Mermin-Kohn-Sham scheme, but employ ground-state approximations to the exchange-correlation (XC) free energy. In the simplest solvable nontrivial model, an asymmetric Hubbard dimer, we calculate the exact many-body energies and the exact Mermin-Kohn-Sham functionals for this system and extract the exact XC free energy. For moderate temperatures and weak correlation, we find this approximation to be excellent. We extract various exact free-energy correlation components and the exact adiabatic connection formula.
Cite
@article{arxiv.1509.03097,
title = {Exact thermal density functional theory for a model system: Correlation components and accuracy of the zero-temperature exchange-correlation approximation},
author = {Justin C Smith and Aurora Pribram-Jones and Kieron Burke},
journal= {arXiv preprint arXiv:1509.03097},
year = {2016}
}