Coupled-channel T-matrix: its lowest-order Born + Lanczos approximants

摘要

Three iterative methods of solution of the Lippmann-Schwinger equations (viz., the method of continued fractions by J.Horacek and T.Sasakawa), its Born-remainder modification and a coupled-channel matrix-continued-fraction generalization are all interpreted as special cases of a common iterative matrix prescription. First, in terms of certain asymmetric projectors P(ne)P(sup +), we re-derive the three particular older methods as different realizations of the well-known Lanczos inversion. Then a generalized iteration method is proposed as a Born-like re-arrangement of any intermediate Lanczos iteration step. A maximal flexibility is achieved in the formalism which might compete with the standard Pade re-summations in practice. 26 refs., 1 tab. (Atomindex citation 27:023573)