Interactions of vector solitons - art. no. 026607

In this paper, we study the interaction of two widely separated vector soli tons in the nonintegrable coupled nonlinear Schrodinger (NLS) equations. Us ing a modification of Karpman-Solov'ev perturbation method, we derive dynam ical equations for the evolution of both solitons' internal parameters. We show that these dynamical equations allow fixed points that correspond to s tationary two-vector-soliton bound states if these solitons have the same p hase in one component (same sign) and pi -phase difference in the other com ponent (opposite sign). However, linear stability analysis indicates that t hese bound states are always unstable due to a phase-related unstable eigen value. We also investigate vector-soliton interactions and show that, in co ntrast to soliton interactions in the single NLS equation, vector solitons repel or attract each other depending not only on their relative phases but also on their initial position separation. Lastly, interaction of an arbit rary number of vector solitons is also studied in brief. All our analytical results are supported by direct numerical simulations.