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arXiv · 1309.2406

Density-matrix functionals from Greens functions

Peter E. Blöchl·Thomas Pruschke·Michael Potthoff
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Abstract

The exact reduced density-matrix functional is derived from the Luttinger-Ward functional of the single-particle Green's function. Thereby, a formal link is provided between diagrammatic many-body approaches using Green's functions on the one hand and theories based on many-body wave functions on the other. This link can be used to explicitly construct approximations for the density-matrix functional that are equivalent to standard diagrammatic re-summation techniques and to non-perturbative dynamical mean-field theory in particular. Contrary to functionals of the Green's-function, the exact density-matrix functional is convex and thus provides a true minimum principle which facilitates the calculation of the grand potential and derived equilibrium properties. The benefits of the proposed Green's-function-based density-matrix functional theory for geometrical structure optimization of strongly correlated materials are discussed.

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Peter E. Blöchl, Thomas Pruschke, Michael Potthoff. 2013-09-10. Density-matrix functionals from Greens functions. https://doi.org/10.1103/physrevb.88.205139

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