Regensburg 2016 – scientific programme

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PV: Plenarvorträge

PV XIX

PV XIX: Plenary Talk

Thursday, March 10, 2016, 08:30–09:15, H1

Many body methods for materials: current status and future developments — •Georg Kresse — University of Vienna, Faculty of Physics, Austria

The properties of all materials arise from the quantum mechanics of their constituent electrons in the field of the nuclei. The solution of the underlying many-electron Schrödinger equation is a non-polynomial hard problem, owing to the interplay of the electron-electron repulsion and the Pauli exclusion principle. The dominant computational method for describing materials has been density functional theory, although this approach involves uncontrolled approximations.

Methods based on an explicit ansatz for the many-electron wavefunction are potentially more accurate and systematically improvable. This talk discusses recent breakthroughs covering quantum chemistry methods as well as many body perturbation theory. Results for a hierarchy of techniques ranging from low order perturbational methods over coupled cluster techniques, up to configuration interaction quantum Monte Carlo are presented for a variety of solids. As for molecular systems, coupled cluster methods are found to be very accurate for weakly correlated electrons, however, the steep increase of the computational cost makes predictions for materials still very timeconsuming. Simpler methods that recover the important ingredients of the many electron solution, such as the random phase approximation to the correlation energy, are discussed alongside illustrative examples for important materials. I finish with an outlook on the challenges lying on the road towards validated first principles predictions.