K. Hayata et M. Koshiba, KINK SOLITONS IN QUADRATIC-CUBIC NONLINEAR DISPERSIVE MEDIA, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 50(4), 1994, pp. 3267-3270
We show analytically that the coexistence of quadratic and cubic nonli
nearities in dispersive media offers kink solitons with the Fermi-Dira
c distribution. The underlying principle and the ubiquity of the prese
nt solitons are discussed.