# Recursive Green's function approach to Feenberg perturbation theory

Source: [Recursive Green's function approach to Feenberg perturbation theory](<https://www.sota2.com/research/paper/68fa39731e209131ce8c2c80>)

Collection index: [llms.txt](<https://www.sota2.com/research/llms.txt>)

Data updated: 2025-10-24T23:32:10.167Z

Authors: K. Ishida

Published: 2019-04-01T16:48:50.000Z

## Abstract

We propose a new procedure by using the recursive Green's functions which remove all the repetition terms from the time-independent perturbation series for finite-level quantum systems. These Green's functions are introduced as a generalization of the Brillouin-Wigner perturbation theory and the calculations of their diagonal elements can naturally give the effective propagators which are equal to the ones in the Feenberg perturbation theory.

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## Original sources and implementation

[Original paper](<https://arxiv.org/abs/1904.00957>)

[PDF](<https://arxiv.org/pdf/1904.00957.pdf>)