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arXiv · 1509.03097

Exact thermal density functional theory for a model system: Correlation components and accuracy of the zero-temperature exchange-correlation approximation

Justin C Smith·Aurora Pribram-Jones·Kieron Burke
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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.

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Justin C Smith, Aurora Pribram-Jones, Kieron Burke. 2016-06-27. Exact thermal density functional theory for a model system: Correlation components and accuracy of the zero-temperature exchange-correlation approximation. https://doi.org/10.1103/physrevb.93.245131

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