2023/05/12 by F. Coppini, Coppini, Francesco, P. M. Santini +1 · 1 citation
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Exactly Solvable and Integrable Systems (nlin.SI) #FOS: Physical sciences #Mathematical Physics (math-ph) #Nonlinear Photonic Systems #Nonlinear Waves and Solitons
paper · pdf · doi:10.48550/arxiv.2305.07339
openalex publication_date 2023/05/12 · openalex created_date 2023/05/17 · openalex updated_date 2026/07/28
The Ablowitz-Ladik (AL) equations are distinguished integrable discretizations of the focusing and defocusing nonlinear Schrödinger (NLS) equations. In a previous paper (arXiv:2305.04857) we have studied the effect of the modulation instability of the homogeneous background solution of the AL equations in the periodic setting, showing in particular that both models exhibit instability properties, and studying, in terms of elementary functions, how a generic periodic perturbation of the unstable background evolves into a recurrence of anomalous waves (AWs). Using the finite gap method, in this paper we extend the recently developed perturbation theory for periodic NLS AWs to lattice equations, studying the effect of physically relevant perturbations of the AL equations on the AW recurrence, like: linear loss, gain, and/or Hamiltonian corrections, in the simplest case of one unstable mode. We show that these small perturbations induce O(1) effects on the periodic AW dynamics, generating three distinguished asymptotic patterns. Since dissipation and higher order Hamiltonian corrections can hardly be avoided in natural phenomena involving AWs, and since these perturbations induce O(1) effects on the periodic AW dynamics, we expect that the asymptotic states described analytically in this paper will play a basic role in the theory of periodic AWs in natural phenomena described by discrete systems. The quantitative agreement between the analytic formulas of this paper and numerical experiments is excellent.