Rice's ansatz for overdamped Ø4 kinks
at finite temperature
Physical Review E
67 027601 (2003)
G.D. Lythe
Department of Applied Mathematics ,
University of Leeds,
LS2 9JT, UK
Franz Mertens
Physikalisches Institut, Universitat Bayreuth,
D-95440 Bayreuth, Germany.
Abstract
The dynamics of a kink driven by noise is analysed using the two
collective variables of the Rice ansatz: position and width. Starting
from a stochastic partial differential equation, with the
Ø4
potential in the overdamped limit, the pair of stochastic
differential equations for the collective variables are derived
without approximation other than the ansatz itself. From the steady
state probability density of the kink width, the diffusivity of a kink
is calculated.