THE PHYSICAL BASIS OF THE UNITARY POLE EXPANSION – SOME REMARKS

Abstract

Publisher Summary This chapter presents some remarks on the physical basis of the unitary pole expansion (UPE). The UPE because of Harms makes use of a separable expansion to the two-nucleon T-matrix. The convergence of the UPE investigated for various potentials is very fast in the sense that taking more terms in the expansion hardly improves over the results obtained. This one term approximation to the UPE is known as the unitary pole approximation (UPA) and is nothing but the simple deuteron problem where the potential V (λ n for n =1 is unity) binds the system with the binding energy B . This chapter explains the problem of examining the physical basis of the higher order terms in the UPE and presents the results. The chapter also discusses the reason for UPE to appear to behave so well despite the unphysical character of these terms.