New kink-antikink solitons of the pair-transition-coupled nonlinear Schrödinger equations

This work presents three new types of coupled periodic waves in a two-component Bose-Einstein condensates (BEC) with pair-transition effects, which all degenerate to distinctive optical shock-wave pairs in the long-wave limit. The newly obtained kink-antikink soliton waveforms exist in two distinct types and are allowable in the repulsive nonlinear interaction case. The analytical nonautonomous periodic wave and kink-antikink solitons for the pair-transition-coupled nonlinear Schr & ouml;dinger (NLS) equations with varying coefficients of nonlinearity, diffraction, pair-transition effects, gain/loss, and harmonic potential are obtained by similarity transformation. As an important application, the nonlinear tunneling effects of these constructed chirped nonautonomous kinkantikink solitons are discussed when they pass through nonlinear barrier and nonlinear well. The results indicate that the kink-antikink solitons form valleys or form peaks as they pass through nonlinear barriers or nonlinear wells, respectively.