On the vortex ring state

Xinle Shang, Pengming Zhang, Zuo Wei

L.-C. Crasovan, Víctor M. Pérez‐García, Ionut Danaila +2 more

We construct three-dimensional structures of topological defects hosted in trapped wave fields, in the form of vortex stars, vortex cages, parallel vortex lines, perpendicular vortex rings, and parallel vortex rings, and we show that the latter exist as robust stationary, collective states of nonrotating Bose-Einstein condensates. We discuss the stability properties of excited states containing several parallel vortex rings hosted by the condensate, including their dynamical and structural stability.

Lihua Pan, Xiaojie Zhu, Qing-Li Zhu +2 more

We investigate dynamics of a vortex ring encountering a coaxial spherical obstacle in Bose-Einstein condensates. For a perfect spherical obstacle, the vortex ring would first expand and then shrink when passing over the obstacle. For the case of a periodically modified spherical obstacle, the circular vortex ring is deformed to be gear shaped during the passing-over process. This gear-shaped vortex ring can evolve into a helical Kelvin-wave state, or split into several smaller vortex rings. In the latter situation, these split vortex rings would travel some distances forwards and then reconnect with each other, forming one new forward-moving Kelvin wave, or two Kelvin waves of different sizes, with the bigger one moving forwards and the smaller one moving backwards.

Andreas H. Trabesinger

Ji, Li, Deng‐Shan Wang, Zhi‐Yong Wu +2 more

The three-dimensional study of the ring vortex solitons is conducted for both attractive and repulsive BECs subject to harmonic potential confinement. A family of stationary ring vortex solitons, which is defined by the radial excitation number and the winding number of the intrinsic vorticity, are obtained numerically for a given atomic interaction strength. We find that stabilities of the ground and radially excited states of the ring vortex soliton are dependent on the winding number differently. The ground state of the ring vortex soliton with the large winding number is unstable dynamically against random perturbation. The radially excited state of the ring vortex soliton with large winding number corresponds to the increased collapse threshold, and therefore can be made stable for sufficiently small atomic interaction strengths. The ground and radially excited states also demonstrate different dynamical evolutions under large atomic interaction strengths. The former exhibits simultaneously symmetrical splitting in the transverse plane, while the latter displays periodically expand-merge cycles in the longitudinal direction.

Carlo F. Barenghi, Thomas Bland, Nick G. Parker