A new variational method to calculate escape rates in bistable systems

We apply the Rayleigh-Ritz variational principle to the inverse of the Smoluchowsky operator in order to calculate the lowest non-vanishing eigenvalue of the Smoluchowsky equation. In contrast to former variational calculations the new method is very insensitive to the choice of the test function. We obtain the asymptotic expansion of the eigenvalue in the limit of vanishing diffusion.