Fluctuation corrections to bubble nucleation.

The fluctuation determinant which determines the preexponential factor of the transition rate for minimal bubbles is computed for the electroweak theory with sinΘW = 0. As the basic action we use the three-dimensional high-temperature action including, besides temperature dependent masses, the TΦ one-loop contribution whcih makes the phase transition first order. The results show that this term (which has then to be subtracted from the exact result) gives the dominant contribution to the one-loop effective action. The remaining correction is of the order of, but in general larger than the critical bubble action. The results for the Higgs field fluctuations are compared with those of an approximate heat kernel computation of Kripfganz et al., good agreement is found for small bubbles, strong deviations for large thin-wall bubbles. e-mail: [email protected]