12 citations · 18 across the 8 of their papers we have counts for
8 papers
Small distance behavior of one-particle Green's functions in electronic structure theory
Heinz-Juergen Flad, Michael Griebel
Within the framework of many-particle perturbation theory, we develop an analytical approach that allows us to determine the small distance behavior of Green's functions and relate…
Fundamental Solutions and Green's Functions for certain Elliptic Differential Operators from a Pseudo-Differential Algebra
Heinz-Jürgen Flad, Gohar Flad-Harutyunyan
We have studied possible applications of a particular pseudo-differential algebra in singular analysis for the construction of fundamental solutions and Green's functions of a cert…
Singular analysis of RPA diagrams in coupled cluster theory
Heinz-Jürgen Flad, Gohar Flad-Harutyunyan
Coupled cluster theory provides hierarchical many-particle models and is presently considered as the ultimate benchmark in quantum chemistry. Despite is practical significance, a r…
Explicit Green operators for quantum mechanical Hamiltonians.~II.~ Edge type singularities of the helium atom
Heinz-Juergen Flad, Gohar Flad-Harutyunyan, Bert-Wolfgang Schulze
We extend our approach of asymptotic parametrix construction for Hamiltonian operators from conical to edge-type singularities which is applicable to coalescence points of two part…
Ellipticity of quantum mechanical Hamiltonians in the edge algebra
Heinz-Juergen Flad, Gohar Harutyunyan
We have studied the ellipticity of quantum mechanical Hamiltonians, in particular of the helium atom, in order to prove existence of a parametrix and corresponding Green operator.…
Asymptotic Parametrices of Elliptic Edge Operators
H. -J. Flad, G. Harutyunyan, B. -W. Schulze
We study operators on a singular manifold, here of conical or edge type, and develop a new general approach of representing asymptotics of solutions to elliptic equations close to…