Comment on "Scattering with absorptive interactions"

Abstract

In a recently published paper, Cassing and collaborators discussed the general tendencies of the motion of the complex poles of the $S$ matrix of a complex potential with increasing absorption. In this Comment, it is pointed out that their conclusions are, in fact, model dependent and therefore are not valid for as wide a class of complex potentials as is suggested. Because of this model dependence of these conclusions, questions about the generalized Levinson's theorem proposed by these authors for complex interaction are raised.NUCLEAR REACTIONS Scattering theory. $S$ matrix for absorptive potentials. Levinson's theorem.