Triaxial Bright Solitons in Bose-Condensed Atomic Vapors

TL;DR

This paper investigates the properties, shape transformations, collective oscillations, and collapse behavior of triaxial bright solitons in Bose-Einstein condensates under anisotropic confinement, including their formation via modulational instability.

Contribution

It provides a detailed variational analysis of triaxial bright solitons, revealing shape changes, stability limits, and formation mechanisms under anisotropic conditions.

Findings

TBSs change shape from cigar-like to disc-like with increasing inter-atomic strength.

Critical inter-atomic strength for collapse is highest in isotropic traps.

Multiple TBSs can form via modulational instability after a sudden change in scattering length.

Abstract

The properties of triaxial bright solitons (TBSs) made of attractive Bose-Einstein condensed atoms under transverse anisotropic harmonic confinement are investigated by using a variational approach. We show that these metastable TBSs change their shape from cigar-like to disc-like by increasing the inter-atomic strength. Moreover, we find that the collective oscillations of a TBS strongly depend on the anisotropy parameter of the external potential. We calculate in detail the properties of TBS close to the collapse, which sets up at a critical value of the inter-atomic strength. This critical strength is maximal in the isotropic (axially symmetric) case and slightly reduces by increasing the anisotropy. Finally, we investigate the formation of multiple TBSs via modulational instability induced by a sudden change of the scattering length from positive to negative.