Relativistic soliton collisions of axion type dark matter

Axion-like scalar fields and the Lane–Emden (LE) truncation of their periodic potential are analyzed as a toy model of dark matter halos. Then, collisions of the well-known kinks in (1+11+1) spacetime dimensions can be mapped to those of localized lumps of the LE equation. Here, we generalize this mapping to (2+12+1)D or even (3+13+1)D and discuss a challenging intrinsic inelastic effect during relativistic soliton collisions.