Negative radiation pressure exerted on kinks

Understand

The interaction of a kink and a monochromatic plane wave in one dimensional scalar field theories is studied.

• It is shown that in a large class of models the radiation pressure exerted on the kink is negative, i.e.
• the kink is {\sl pulled} towards the source of the radiation.
• This effect has been observed by numerical simulations in the $\phi^4$ model, and it is explained by a perturbative calculation assuming that the amplitude of the incoming wave is small.