Role of higher-order interactions on the modulational instability of Bose-Einstein condensate trapped in a periodic optical lattice

TL;DR

This paper explores how higher-order interactions influence the modulational instability in Bose-Einstein condensates within optical lattices, revealing new behaviors and providing both analytical and numerical insights.

Contribution

It introduces a variational framework to analyze higher-order effects on MI in BECs and demonstrates their significant impact through combined analytical and numerical methods.

Findings

Higher-order interactions alter MI characteristics in BECs.

Numerical results confirm the semi-analytical predictions.

High-density BECs show new MI behaviors due to these interactions.

Abstract

In this paper, we investigate the impact of higher-order interactions on the modulational instability (MI) of Bose-Einstein Condensates (BECs) immersed in an optical lattice potential. We derive the new variational equations for the time evolution of amplitude, phase of modulational perturbation, and effective potential for the system. Through effective potential techniques, we find that high density attractive and repulsive BECs exhibit new character with direct impact over the MI phenomenon. Results of intensive numerical investigations are presented and their convergence with the above semi analytical approach is brought out.