Discrete breathers in BEC with two- and three-body interactions in optical lattice

TL;DR

This paper studies discrete breathers in Bose-Einstein condensates within optical lattices, analyzing stability conditions influenced by two- and three-body interactions, and confirms findings through numerical simulations.

Contribution

It introduces a cubic-quintic discrete nonlinear Schrödinger model for BECs with multi-body interactions and derives new stability conditions for discrete breathers.

Findings

Quintic nonlinearity affects stability of localized modes

Analytical stability conditions match numerical simulations

Conditions for breather generation depend on interaction parameters

Abstract

We investigate the properties of discrete breathers in a Bose-Einstein condensate with two- and three-body interactions in optical lattice. In the tight-binding approximation the Gross-Pitaevskii equation with periodic potential for the condensate wavefunction is reduced to the cubic-quintic discrete nonlinear Schr\"odinger equation. We analyze the regions of modulational instabilities of nonlinear plane waves. This result is important to obtain the conditions for generation of discrete solitons(breathers) in optical lattice. Also using the Page approach, we derive the conditions for the existence and stability for bright discrete breather solutions. It is shown that the quintic nonlinearity brings qualitatively new conditions for stability of strongly localized modes. The numerical simulations conform with the analytical predictions.