Symmetry Breaking and Self-trapping of a Dipolar Bose-Einstein Condensate in a Double-well Potential

TL;DR

This paper investigates how the orientation of dipoles influences the ground state and dynamic self-trapping phenomena of a dipolar Bose-Einstein condensate in a double-well potential, combining numerical and analytical models.

Contribution

It introduces a detailed analysis of dipole orientation effects on self-trapping and Josephson oscillations, highlighting the limitations of the two-mode model.

Findings

Dipole orientation significantly alters the onset of self-trapping.

The two-mode model fails to accurately predict Josephson oscillation rates.

Numerical results confirm the impact of dipole alignment on condensate dynamics.

Abstract

The quantum self-trapping phenomenon of a Bose-Einstein condensate (BEC) represents a remarkable nonlinear effect of wide interest. By considering a purely dipolar BEC in a double-well potential, we study how the dipole orientation affects the ground state structure and the transition between self-trapping and Josephson oscillation in dynamics. Three-dimensional numerical results and an effective two-mode model demonstrate that the onset of self-trapping of a dipolar BEC can be radically modified by the dipole orientation. We also analyze the failure of the two-mode model in predicting the rate of Josephson oscillations. We hope that our results can motivate experimental work as well as future studies of self-trapping of ultracold dipolar gases in optical lattices.