Semiclassical calculation of the nucleation rate for first order phase transitions in the 2-dimensional phi^4-model beyond the thin wall approximation

In many systems in condensed matter physics and quantum field theory, first order phase transitions are initiated by the nucleation of bubbles of the stable phase. Traditionally, this process is described by the semiclassical nucleation theory developed by Langer and, in the context of quantum field theory, by Callan and Coleman. They have shown that the nucleation rate can be written in th e form of the Arrhenius law: = Ae −Hc . Here Hc is the energy of the critical bubble, and the prefactor A can be expressed in terms of the determinant of the operator of fluctuations near the critical bubble state. It is not possible to find explicit expressions