Modulational instability of matter waves under strong nonlinearity management

TL;DR

This paper investigates how strong temporal nonlinearity-management affects the modulational instability of matter waves in Bose-Einstein condensates, revealing critical thresholds and effects on soliton behavior.

Contribution

It introduces a novel analysis of modulational instability under strong nonlinearity-management in BECs, including effects on optical lattice dispersion and soliton atom number.

Findings

Transformation of dispersion curve loops due to nonlinearity-management

Critical nonlinearity-management strength alters instability character

Enhanced atom number in nonlinearity-managed gap solitons

Abstract

We study modulational instability of matter-waves in Bose-Einstein condensates (BEC) under strong temporal nonlinearity-management. Both BEC in an optical lattice and homogeneous BEC are considered in the framework of the Gross-Pitaevskii equation, averaged over rapid time modulations. For a BEC in an optical lattice, it is shown that the loop formed on a dispersion curve undergoes transformation due to the nonlinearity-management. A critical strength for the nonlinearity-management strength is obtained that changes the character of instability of an attractive condensate. MI is shown to occur below(above) the threshold for the positive (negative) effective mass. The enhancement of number of atoms in the nonlinearity-managed gap soliton is revealed.