Adiabatic connection fluctuation dissipation theorem density functionals beyond the random phase approximation

The random phase approximation (RPA) is an increasingly popular starting point for the construction of improved correlation energy functionals. As opposed to semi-local approximations, RPA-based functionals do not suffer from Coulomb self-interaction and naturally include van der Waals interactions; the price is higher computational cost. To compete with traditional correlated wavefunction methods, it is necessary to go beyond the bare RPA. I will analyze successes and failures of recent attempts to do so [1,2], and outline promising future directions. \newline [1] Z. Yan, J. P. Perdew, and S. Kurth, \textit{Phys. Rev. B} \textbf{61} (2000), 16430. \newline [2] F. Furche and T. Van Voorhis, \textit{J. Chem. Phys.} \textbf{122} (2005), 164106.