We demonstrate numerically that an oscillation mode in 1+1 dimensions ( eg a breather or an oscillon ) can decay into a kink-antikink pair by a sudden distortion of the evolution potential which occurs within a certain time or space domain .
In particular , we consider the transition of a sine-Gordon potential into a \Phi ^ { 4 } potential .
The breather field configuration is assumed to initially evolve in a sine-Gordon potential with velocity v and oscillation frequency \omega .
We then consider two types of numerical experiments : a .
An abrupt transition of the potential to a \Phi ^ { 4 } form at t _ { 0 } = 0 over the whole 1-dimensional lattice and b .
The impact of the breather on a region x > x _ { 0 } = 0 where the potential has the \Phi ^ { 4 } form which is different from the sine-Gordon form valid at x < x _ { 0 } = 0 .
We find that in both cases there is a region of parameters ( v, \omega ) such that the breather decays to a kink-antikink pair .
This region of parameters for kink-antikink formation is qualitatively similar with the parameter region where the energy of the breather exceeds the energy of the kink-antikink pair in the \Phi ^ { 4 } potential .
We demonstrate that the same mechanism for soliton formation is realized when using a gaussian oscillator ( oscillon ) instead of a breather .
We briefly discuss the implications of our results for realistic experiments as well as their extension to soliton formation in two and three space dimensions .