Efficient evaluation of AGP reduced density matrices.
@article{Khamoshi2019EfficientEO, title={Efficient evaluation of AGP reduced density matrices.}, author={Armin Khamoshi and Thomas M. Henderson and Gustavo E. Scuseria}, journal={The Journal of chemical physics}, year={2019}, volume={151 18}, pages={ 184103 } }
We propose and implement an algorithm to calculate the norm and reduced density matrices (RDMs) of the antisymmetrized geminal power of any rank with polynomial cost. Our method scales quadratically per element of the RDMs. Numerical tests indicate that our method is very fast and capable of treating systems with a few thousand orbitals and hundreds of electrons reliably in double-precision. In addition, we present reconstruction formulas that allow one to decompose higher order RDMs in terms…
15 Citations
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References
SHOWING 1-10 OF 32 REFERENCES
Optimization of density matrix functionals by the Hartree–Fock–Bogoliubov method
- Chemistry
- 2002
It is demonstrated that the “corrected Hartree–Fock” (CHF) density matrix functional proposed by Csanyi and Arias is identical with the Hartree–Fock–Bogoliubov (HFB) functional of the generalized…
Calculation of optimal generalized antisymmetrized geminal-power (projected—Bardeen-Cooper-Schrieffer) functions and their associated excitation spectrum
- Physics
- 1980
The generalized antisymmetrized geminal-power (GAGP) function, shown to be the ground state for the oneparticle-hole propagator, can be computed using the rather simple properties of its reduced…
Geminal-based configuration interaction
- Computer ScienceThe Journal of Chemical Physics
- 2019
This work considers a form of configuration interaction based upon the AGP wave function and taking advantage of its killing operators to construct an excitation manifold, reducing to standard single-determinant--based CI in the limit in which AGP reduces to a single determinant.
A New Mean-Field Method Suitable for Strongly Correlated Electrons: Computationally Facile Antisymmetric Products of Nonorthogonal Geminals.
- PhysicsJournal of chemical theory and computation
- 2013
This work focuses on an approach where, in each geminal, only one of the orbitals in a reference Slater determinant is occupied, and gives good results for atoms and small molecules.
Structure of Fermion Density Matrices. II. Antisymmetrized Geminal Powers
- Physics
- 1965
Functions which can be expressed as an antisymmetrized power of a single two‐particle function (a geminal) occur in the BCS ansatz. They constitute a comparatively tractable generalization of a…
Projected quasiparticle theory for molecular electronic structure.
- PhysicsThe Journal of chemical physics
- 2011
This work derives and implements symmetry-projected Hartree-Fock-Bogoliubov equations and applies them to the molecular electronic structure problem, showing that the resulting method yields a comprehensive black-box treatment of static correlations with effective one-electron (mean-field) computational cost.
Seniority and orbital symmetry as tools for establishing a full configuration interaction hierarchy.
- PhysicsThe Journal of chemical physics
- 2011
It is found that the symmetry constraints that are normally placed on the spatial orbitals greatly affect the convergence rate of the FCI expansion, and the energy relevance of the seniority zero sector increases dramatically if orbitals of broken spatial symmetry are allowed in the wave function construction.
A new approach to density matrix functional theory
- Chemistry, Physics
- 2003
Starting from a pair-excitation multiconfiguration self-consistent field approach considering pairwise excitations of two electrons of opposite spin from a single occupied molecular orbital to a…