Sine-gordon kink-antikink generation on spatially periodic potentials

A spatially periodic perturbation can lead to a breakup of large-amplitude sine-Gordon breathers into kink and anti kink solutions, each oscillating around a minimum of the perturbing potential. This behavior can be understood by studying the effective potential experienced by the breather (bound kink-antikink) or the (free) kink-antikink solution as long as kink and antikink are sufficiently far apart. The resulting kinks and antikinks move independently and nearly radiationlessly in the presence of the perturbation and can travel arbitrarily far for sufficiently large initial kinetic energy. Upon interacting with each other they are strongly affected by the perturbation, lose energy by radiating, and can end in a bound state having the character of a distorted breather.We acknowledge support by the U .S. Department of Energy. A. S. is partially supported by the Comisión Interministerial de Ciencia y Tecnologia (CICyT) of Spain under Grant No. MAT90-0544Publicad