Exchange Current Effects in the Deuteron

Abstract

It is well known that the existence of charge carrying nuclear fields, resulting in an exchange of charge between nucleons, also gives rise to additional electromagnetic interaction terms for the nuclear system. It is commonly assumed that these effects are zero for the deuteron ground state, on account of the symmetry properties of the exchange current. The present investigation aims to draw attention to the fact that this conclusion is only true in the adiabatic approximation, which neglects the recoil of the nucleons. In the expression for the electromagnetic interaction of charge exchanging nucleons in motion, nuclear "two-particle currents" appear, in addition to the meson currents encountered in the adiabatic approximation. Whereas the latter are antisymmetric under charge exchange of a nucleon pair, the former are not, and give rise to electromagnetic exchange effects for the deuteron ground state.