On the theory of scalar pair production by a potential barrier

Abstract

The problem of the scalar pair production by a one-dimensional vector-potential Am(x₃) is reduced to the S-matrix formalism of the theory with an unstable vacuum. Our choice of in- and out-states does not coincide with that of other authors and we argue extensively in favor of our choice. We show that the norm of a solution of the wave equation is determined by one of the amplitude of its asymptotic form for x₃→±∞. For the constant electric field we obtain the scalar particle propagator in terms of the stationary states and show that with our choice of in- and out-states it has the form dictated by the general theory.