Nonperturbative effects on nucleation.

A nonperturbative correction to the thermal nucleation rate of critical bubbles in a first-order phase transition is estimated. Using a simple model of a scalar field in a double-well potential, we obtain a corrected potential which incorporates the free-energy density available from large-amplitude fluctuations, which is not included in the usual perturbative calculation. As an application of our method, we show how these corrections can both qualitatively and quantitatively explain anomalously high nucleation rates observed in 2D numerical simulations.