Hi Axel,

Thanks for your answer. It talks about a different kind of kink soliton.

In fact, we know two kinds of kink solitons in the literature: solitons for which the plot of the real part (or the amplitude) of the wave function vs. space resembles a double kink in a pipe. The first kind (kink in the real part) is referred to as Dark soliton. Many experimental observations of such a soliton have been reported (among which the Ref. your cited in your response). However, I have not yet learnt about the experimental observation of the second kind of kink soliton. That is the point in my question.

Regards,

Etienne