Adiabatic connection at negative coupling strengths

Abstract

The adiabatic connection of density functional theory (DFT) for electronic systems is generalized here to negative values of the coupling strength $\alpha$ (with {\em attractive} electrons). In the extreme limit $\alpha \to -\infty$ a simple physical solution is presented and its implications for DFT (as well as its limitations) are discussed. For two-electron systems (a case in which the present solution can be calculated exactly), we find that an interpolation between the limit $\alpha \to -\infty$ and the opposite limit of infinitely strong repulsion ($\alpha \to +\infty$) yields a rather accurate estimate of the second-order correlation energy $E\cor\glt[ρ]$ for several different densities $\rho$, without using virtual orbitals. The same procedure is also applied to the Be isoelectronic series, analyzing the effects of near-degeneracy.

9 pages, submitted to PRA

References in corpus (8)

• Density functional theory for strongly interacting electrons
• Strong correlations via constrained-pairing mean-field theory
• Two electrons on a hypersphere: a quasi-exactly solvable model
• Ground state of two electrons on a sphere
• Adiabatic Connection in the Low-Density Limit
• Correlation energy of two electrons in the high-density limit
• Adiabatic Connection for Strictly-Correlated Electrons
• Accurate Adiabatic Connection Curve Beyond the Physical Interaction Strength

Cited by in corpus (8)

• Excited states of spherium
• Hooke's law correlation in two-electron systems
• Challenging the Lieb-Oxford Bound in a systematic way
• Ground state of two electrons on concentric spheres
• Quantifying errors of the electron-proton/muon correlation functionals through the Kohn-Sham inversion of a two-component model system
• Restoring the Point-and-Charge Gradient Expansion for the Strong Interaction Density Functionals
• Exotic Harmonium Model: Exploring Correlation Effects of Attractive Coulomb Interaction
• Transient Uniform Electron Gases