High energy density spots and production of kink-antikink pairs in particle collisions

Creation of solitons as kink-antikink pairs from particles is investigated, in the ϕ4 model. Particle-like states are simulated by two widely separated identical wave trains which are propagated toward collision point from both sides in a trivial background. The maximal energy density that can be achieved in the collisions of the particle-like wave trains is investigated numerically for different wave train parameters. Maximum energy and number of kink-antikink pairs created after the collision is calculated and the relation between them are studied. It is shown numerically that, if the number of created kink-antikink pairs are N, the maximal energy density should be at least equal to N2∕2.