International Workshop on 'New challenges in Reduced Density Matrix Functional Theory: Symmetries, time-evolution and entanglement'
Combining methods without double counting in RDMFT contextAndreas Savin
Ideas that were presented as seamlessly combining wave function methods with density functionals can be seen from a reduced density matrix perspective:
• some derivations appear natural in this context,
• the wave function part can be replaced by a reduced density matrix part .
The usage of density functionals can be motivated by the slow convergence of the kinetic energy with basis set size, due to the singularity in the Coulomb potential . Two strategies are discussed: (a) using natural orbitals [3, 4] and (b) using orbital spaces [5, 6]. Furthermore, the adiabatic connection can be reformulated, and applied from different perspectives:
• for computing the correlation energy using the kinetic energy evolution [7, 8, 9],
• by using extrapolation [10, 11, 12].
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