Vacuum decay by inverse scattering

We discuss the decay of false vacua which originate from quantum mechanical effects. In particular we examine the 1/N expansion of the O(N)lambdaphi4 model. This model has an effective potential which is complex for large values of the field. In a previous paper we showed that this effective potential could not be used to calculate the decay rate directly. In the present work we show that the vacuum can decay via poles in the effective action which are evident when it is written in terms of scattering variables. (orig.)