Perturbation-Adapted Perturbation Theory

Abstract

A new general approach is introduced for definining an optimum zero-order Hamiltonian for Rayleigh-Schrödinger perturbation theory. Instead of taking the operator directly from a model problem, it is constructed to be a best fit to the exact Hamiltonian within any desired functional form. When applied to many-body perturbation theory for electrons, strongly improved convergence is observed in cases where the conventional Fock hamiltonian leads to divergence or slow convergence.

arXiv comment4 pages, 2 figures, minor revisions

References in corpus (4)

• A driven similarity renormalization group approach to quantum many-body problems
• A numerical canonical transformation approach to quantum many body problems
• Pade-resummed high-order perturbation theory for nuclear structure calculations
• Perturbation Theory in the Complex Plane: Exceptional Points and Where to Find Them