Swinging waves in Ablowitz-Ladik equation

Seminars

Laboratory of Information Technologies

Seminar of the Scientific Department of Computational Physics

Date and Time: Thursday, 22 January 2026, at 3:00 PM

Venue: room 310, Meshcheryakov Laboratory of Information Technologies, online on Webinar

Seminar topic: “Swinging waves in the Ablowitz-Ladik equation “

Speaker: Igor Barashenkov

Authors: Igor Barashenkov, Frank Smuts (University of Cape Town)

Abstract:

Researchers built new families of exact cnoidal wave and soliton solutions of the focusing and defocusing Ablowitz-Ladik equations. Unlike cnoidal waves that were obtained by earlier authors, the phase variable of the new solutions exhibits a nonlinear dependence on time and site number – the wave “swings”. The approach hinges on the existence of a two-point map governing the absolute value of the complex field; this map gives rise to standing waves centred arbitrarily relative to the lattice sites. Having derived stationary solutions, scientists leveraged them to construct waves propagating with a nonzero velocity. The localised members of the new family comprise dark solitons with the nontrivial asymptotic behaviour. Researchers derived an explicit quantisation rule for the velocity of the wave circulating in a closed loop of N sites.