Tensor hypercontracted ppRPA: Reducing the cost of the particle-particle random phase approximation from O(r 6) to O(r 4)
Exchange-correlation energy from pairing matrix fluctuation and the particle-particle random phase approximation
Double, Rydberg and charge transfer excitations from pairing matrix fluctuation and particle-particle random phase approximation
Exchange-correlation energy from pairing matrix fluctuation and the particle-particle random-phase approximation