Transverse Instability of Straight Vortex Lines in Dipolar Bose-Einstein Condensates

The physics of vortex lines in dipolar condensates is studied. Because of the nonlocality of the dipolar interaction, the 3D character of the vortex plays a more important role in dipolar gases than in typical short-range interacting ones. In particular, the dipolar interaction significantly affects the stability of the transverse modes of the vortex line. Remarkably, in the presence of a periodic potential along the vortexline, the spectrum of transverse modes shows a rotonlike minimum, which eventually destabilizes the straight vortex when the BEC as a whole is still stable, opening the possibility for new scenarios for vortex-line configurations in dipolar gases.

Figure 1

Dispersion $ϵ(q)$ as a function of $q\xi$, in the absence of an additional optical lattice, and various values of $\beta =0$ (solid line), 1.0 (dashed line), and $-0.98$ (dotted line).

Figure 2

Dispersion $ϵ(q)$ as a function of $q\xi$ for $m/m^{*}=0.23$, and $\beta =-0.59$.

Figure 3

Stable or unstable regimes for straight-vortex lines.