Nucleon-nucleon dynamics from variational matrix Padé approximants

Abstract

First we summarize and analyze the operator Pade approximant (O.P.A.) method in potential scattering. These approximants are derived from a variational principle for the time evolution operator. The lowest approximant, constructed from the first two terms of the perturbation expansion of the off‐shell scattering matrix, is shown to be the exact solution of the corresponding Schrodinger equation. The actual computation of the O.P.A. requires the inversion of an operator which is achieved by replacing the O.P.A. requires the inversion of an operator which is achieved by replacing the O.P.A. by a M.P.A. (matrix Pade approximant). The mesh points on which the calculation is performed are variational parameters for each energy, angular momentum, parity, and internal quantum numbers and are determined by the Schwinger variational parameters for each energy, angular momentum, parity, and internal quantum numbers and are determined by the Schwinger variational principle for phase shifts. For potentials so strong ...