The collision of two-kinks revisited: the creation of kinks and lump-like defects as metastable states

Abstract

We present a more detailed numerical investigation of the head-on collision of a two-kink/two-antikink system. We identified the escape of oscillon-like configurations as a pair of kinks of the standard $\phi^4$ model moving apart from each other. New pieces of evidence support that the lump-like defects can emerge from the two-kinks interaction to form metastable configurations. Moreover, these configurations signalize the windows of escape that have a fractal structure similar to the $n$-bounce sequence when the kinks of $\phi^4$ interact. As the last piece of the numerical experiment, we show that by perturbing conveniently a lump-like defect it is possible to recover another lump-like configuration as a metastable configuration.