Cross-symmetric dipolar-matter-wave solitons in double-well chains

TL;DR

This paper studies novel cross-symmetric dipolar matter-wave solitons in a double-well chain of dipolar Bose-Einstein condensates, revealing how dipole orientation affects soliton symmetry, stability, and the emergence of asymmetric states.

Contribution

It introduces a new class of cross-symmetric solitons in a coupled discrete system with dipole-dipole interactions, considering arbitrary dipole orientations and PT-symmetry effects.

Findings

Discovery of on-site- and off-site-centered cross-symmetric solitons.

Identification of a narrow region with asymmetric solitons at the boundary.

Stability regions for PT-symmetric solitons.

Abstract

We consider a dipolar Bose-Einstein condensate trapped in an array of two-well systems with an arbitrary orientations of the dipoles relative to the system's axis. The system can be built as a chain of local traps sliced into two parallel lattices by a repelling laser sheet. It is modelled by a pair of coupled discrete Gross-Pitaevskii equations, with dipole-dipole self- and cross-interactions. When the dipoles are not polarized perpendicular or parallel to the lattice, the cross-interaction is asymmetric, replacing the familiar symmetric two-component discrete solitons by two new species of cross-symmetric ones, on-site- and off-site-centered, which are strongly affected by the orientation of the dipoles and separation between the parallel lattices. A very narrow region of intermediate asymmetric discrete solitons is found at the boundary between the on- and off-site families. Two different types of solitons in the $\mathcal{PT}$%-symmetric version of the system are constructed too, and stability areas are identified for them.