Starts 15 May 2013 17:00

Ends 15 May 2013 20:00

Central European Time

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Joint ICTP/SISSA Colloquium on Condensed Matter Physics: "Correlated electron calculations with polynomial scaling"

Starts 15 May 2013 17:00

Ends 15 May 2013 20:00

Central European Time

ICTP

Leonardo da Vinci Building Luigi Stasi Seminar Room

Strada Costiera, 11
I - 34151 Trieste (Italy)

Due to its simplicity and numerical efficiency, density functional theory (DFT) is the most popular approach for calculating the electronic structure of large molecules and materials. Nevertheless, the accuracy of DFT is not always satisfactory and the search for improved approximations that avoid self-interaction and capture strong electron correlations faces severe difficulties. In this talk I will present an alternative approach in which the one- and two-particle density matrices needed to compute the ground-state energy, are explicit functionals of the natural spin orbital states and their joint occupation probabilities. The scheme is parameter-free and not affected by self-interaction error. In its simplest formulation, restricted to the seniority zero sector of the many-particle Hilbert space, it has the same scaling of Hartree-Fock theory. Yet, it describes strong correlations as demonstrated by calculating the dissociation energy curves of diatomic molecules and linear chains of hydrogen atoms. Improved approximations that retain polynomial cost but are not limited to seniority zero will be also discussed.

- M. Poropat