The random-phase approximation (RPA) for the electron correlation energy, combined with the exact-exchange (EX) energy, represents the state-of-the-art exchange-correlation functional within density-functional theory. However, the standard RPA practice--evaluating both the EX and the RPA correlation energies using Kohn-Sham (KS) orbitals from local or semilocal exchange-correlation functionals-...

We present a controlled method for computing the exchange coupling in strongly correlated onedimensional electron systems. The asymptotically exact relation between the exchange constant and the pair-correlation function of spinless electrons is derived. Explicit results are obtained for thin quantum rings with realistic Coulomb interactions, by calculating this function via a many-body instant...

The study of warm dense matter, widely existing in nature and laboratories, is challenging due to the interplay quantum classical fluctuations. We develop a variational diagrammatic Monte Carlo method determine exchange-correlation kernel $K_{\rm XC}(q;T)$ electron gas for broad range temperature $T$ momentum $q$. observe several interesting physics, including $T$-dependent evolution hump struc...

We compare two different approaches to investigations of many-electron systems. The first is the Hartree-Fock (HF) method and the second is the Density Functional Theory (DFT). Overview of the main features and peculiar properties of the HF method are presented. A way to realize the HF method within the Kohn-Sham (KS) approach of the DFT is discussed. We show that this is impossible without inc...

Submitted for the MAR16 Meeting of The American Physical Society Study of adiabatic connection in ground-state density functional theory MANOJ HARBOLA, RABEET CHAUHAN, Indian Inst of Tech-Kanpur, RABEET S. CHAUHAN COLLABORATION — By employing modified [1] variational form of Le-Sech wavefunctions [2] for two-electron systems, accurate wavefunctions for He-like atoms corresponding to their groun...