Density-matrix functionals from Green's functions

Peter E. Blöchl

doi:10.1103/PhysRevB.88.205139

Density-matrix functionals from Green's functions

2013-11-26

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DOI：10.1103/PhysRevB.88.205139

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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 resummation techniques and to nonperturbative 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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NATURAL SPIN-ORBITALS

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Density-matrix functionals from Green's functions

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