Attraction-induced dynamical stability of a Bose-Einstein condensate in a nonlinear lattice

TL;DR

This paper investigates how spatially periodic interactions in a Bose-Einstein condensate lead to a novel attraction-induced dynamical stability, especially near the zone boundary, through analysis of energy bands and stability properties.

Contribution

It introduces the concept of attraction-induced dynamical stability in nonlinear lattices, demonstrating how localized density regions enhance superfluid stability in BECs.

Findings

Stability near the zone boundary is enhanced by attraction-induced localization.

Higher-periodic states become more stable with increased nonlinear interaction strength.

A new mechanism for dynamical stability in nonlinear lattice systems is identified.

Abstract

We study multiple-period Bloch states of a Bose-Einstein condensate with spatially periodic interactomic interaction. Solving the Gross-Pitaevskii equation for the continuum model, and also using a simplified discrete version of it, we investigate the energy-band structures and the corresponding stability properties. We observe a new "attraction-induced dynamical stability" mechanism caused by the localization of the density distribution in the attractive domains of the system and the isolation of these higher-density regions. This makes the superfluid stable near the zone boundary, and also enhances the stability of higher-periodic states if the nonlinear interaction strength is sufficiently high.