Soliton Molecules In Dipolar Bose-Einstein Condensates

TL;DR

This paper investigates the formation, stability, and properties of soliton molecules in dipolar Bose-Einstein condensates, revealing new regimes and behaviors driven by the interplay of contact and dipolar interactions.

Contribution

It introduces the existence of stable soliton molecules, including trimers, in dipolar BECs and analyzes their unique excitation behaviors and regimes.

Findings

Identification of two soliton regimes: 1D with purely repulsive DDI and 3D with attractive DDI.

Discovery of stable soliton trimers where molecular trimers are absent.

Nontrivial excitation behavior due to competition between on-site and inter-site DDI.

Abstract

Dipolar interactions support the formation of inter-site soliton molecules in a stack of quasi-1D traps. We show that the stability and properties of individual solitons, and soliton molecules in such a geometry crucially depend on the interplay between contact and dipolar interactions. In particular, two different quasi-1D soliton regimes are possible: a 1D soliton characterized by purely repulsive DDI and a 3D soliton for which a sufficiently large dipole moment renders the DDI attractive. Furthermore, we find that contrary to the case of dimers of polar molecules, the soliton dimers exhibit a nontrivial behavior of the elementary excitations that stems from the competition between on-site and inter-site DDI. Finally, we prove the existence of soliton trimers in a regime where molecular trimers do not occur. We demonstrate that the soliton molecules that we report are well feasible under realistic experimental conditions.