title: Conservation of connectivity of model-space effective interactions under a class of similarity transformation.
abstract: Effective interaction operators usually act on a restricted model space and give the same energies (for Hamiltonian) and matrix elements (for transition operators, etc.) as those of the original operators between the corresponding true eigenstates. Various types of effective operators are possible. Those well defined effective operators have been shown to be related to each other by similarity transformation. Some of the effective operators have been shown to have connected-diagram expansions. It is shown in this paper that under a class of very general similarity transformations, the connectivity is conserved. The similarity transformation between Hermitian and non-Hermitian Rayleigh-Schrodinger perturbative effective operators is one of such transformations and hence the connectivity can be deducted from each other.
authors.affiliation: Institute of Applied Physics and College of Electronic Engineering, Chongqing University of Post and Telecommunications, Chongqing 400065, China.
authors.forename: Chang-Kui
authors.initials: CK
authors.lastname: Duan
authors.forename: Yungui
authors.initials: Y
authors.lastname: Gong
authors.forename: Hui-Ning
authors.initials: HN
authors.lastname: Dong
authors.forename: Michael F
authors.initials: MF
authors.lastname: Reid