Om. Kiselev, THE INTERACTION OF A KINK WITH A BREATHER OF SMALL AMPLITUDE IN THE PHI(4)-MODEL, Russian journal of mathematical physics, 5(1), 1997, pp. 29-46
The leading term of a formal asymptotic solution for the phi(4)-model
is constructed in the form of a perturbed kink. The formal asymptotic
solution is valid until times of the order of epsilon(-2), where epsil
on is the perturbation parameter.