Fluxon analogues and dark solitons in linearly coupled Bose-Einstein condensates

TL;DR

This paper investigates fluxon analogues and dark solitons in linearly coupled Bose-Einstein condensates, analyzing their stability and the effects of external potentials using theoretical models.

Contribution

It introduces a variational approach to study fluxon analogues and dark solitons, highlighting how external potentials influence their stability and proposing control methods.

Findings

Magnetic traps can destabilize fluxon analogues.

Controlling linear coupling stabilizes fluxon analogues.

Theoretical models match numerical simulations.

Abstract

Two effectively one-dimensional parallel coupled Bose-Einstein condensates in the presence of external potentials are studied. The system is modelled by linearly coupled Gross-Pitaevskii equations. In particular, grey-soliton-like solutions representing analogues of superconducting Josephson fluxons as well as coupled dark solitons are discussed. Theoretical approximations based on variational formulations are derived. It is found that the presence of a magnetic trap can destabilize the fluxon analogues. However, stabilization is possible by controlling the effective linear coupling between the condensates.