Partial delocalization of two-component condensates in optical lattices

TL;DR

This paper investigates how interspecies interactions influence localized modes in two-component Bose-Einstein condensates within optical lattices, revealing regimes of partial delocalization, instability, and existence limits through numerical simulations.

Contribution

It introduces a detailed analysis of delocalization regimes in two-component condensates, highlighting the critical interspecies scattering length for controllable manipulation.

Findings

Identified three regimes of delocalization in two-component condensates.

Discovered a critical interspecies scattering length for component manipulation.

Showed that one component can become irreversibly destroyed beyond a threshold.

Abstract

We study management of localized modes in two-component (spinor) Bose-Einstein condensates embedded in optical lattices by changing interspecies interactions. By numerical integration of the coupled Gross-Pitaevskii equations, we find three different regimes of the delocalizing transition: i) the partial delocalization when the chemical potential of one of the components collapses with a gap edge and the respective component transforms into a Bloch state, while the other component remains localized; ii) the partial delocalization as consequence of instability of one of the components; and iii) the situation where the vector soliton reaches limits of the existence domain. It is shown that there exists a critical value for interspecies scattering length, below which solutions can be manipulated and above which one of the components is irreversibly destroyed.