Tools for Thermal Density Functional Theory

Exact conditions have been used in ground-state density functional theory (DFT) for development and analysis of approximations. New exact conditions, as presented here, are vital to developing good approximations for thermal ensembles. Similar to methods used in the ground state, scaling leads to bounds and limiting behaviors and allows investigation of the thermal adiabatic connection. Analysis of common thermal DFT approximations using exact conditions will be discussed.