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Flexible Ansatz for N-Body Perturbation Theory
Ramón Alain Miranda-Quintana1, Taewon D Kim1,2, Rugwed A Lokhande1
1Department of Chemistry and Quantum Theory Project, University of Florida, Gainesville, Florida 32603, United States.
Abstract:
We propose a new perturbation theory framework that can be used to help with the projective solution of the Schrödinger equation for arbitrary wave functions. This Flexible Ansatz for N-body Perturbation Theory (FANPT) is based on our previously proposed Flexible Ansatz for the N-body Configuration Interaction (FANCI). We derive recursive FANPT expressions, including arbitrary orders in the perturbation hierarchy. We show that the FANPT equations are well-behaved across a wide range of conditions, including static correlation-dominated configurations and highly nonlinear wave functions.
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