Article,
Transition from Discrete to Continuous Spectra
Physical Review Online Archive (Prola), 103 (5): 1565--1571 (September 1956)
DOI: 10.1103/physrev.103.1565
Abstract
The stationary states of a system bound in a spherical box and additionally subjected to a perturbation of finite range are studied in the limit as the box radius becomes infinite. The transition from formal discrete-spectrum theory to formal scattering theory is carried out explicitly by two different methods. It is shown quite generally (i.e.; even when the total Hamiltonian is not separable) that the level shift produced by the perturbation is proportional to the corresponding scattering phase shift.
