2019/04/01 by Ishida, K.
#81Q05 #FOS: Physical sciences #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.1904.00957
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.