Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 20: Poster Session: Correlated Electrons 2
TT 20.7: Poster
Montag, 20. März 2017, 15:00–19:00, P2-OG1
Reduced Density-Matrix Functionals from Green's Functions — •Heike Eisenlohr1, Ebad Kamil1, Robert Schade2, and Peter Blöchl2 — 1Institute for Theoretical Physics, University of Goettingen, Goettingen, Germany — 2Institute for Theoretical Physics, Clausthal University of Technology, Clausthal, Germany
A new method for the electronic structure calculations of strongly correlated materials is explored. The long-term goal is the efficient simulation of such materials in the context of first-principles calculations. The method rests on an exact theorem, which expresses the one-particle reduced density-matrix functional by many-particle Green's functions via the Luttinger-Ward functional [1]. This theorem makes contact between ground state approaches such as reduced density matrix functional theory (rDMFT) and Feynman diagrams and even non-perturbative many-particle methods. The theorem suggests new approximate methods for the construction of density matrix functionals, namely to first establish an empirical Green's function as a direct function of the reduced density matrix, and secondly to evaluate the energy for this Green's function with many-particle methods. We present results based on a diagrammatic expansion and discuss difficulties and successes on the example of the Hubbard dimer.
This work is supported by the Deutsche Forschungsgemeinschaft via FOR1346 through project P9.
[1] P. E. Blöchl et al., Phys. Rev. B 88, 205139 (2013).