Splitting instability of a multiply charged vortex in a Bose-Einstein condensate

Mikko Möttönen, Tomoya Isoshima, M.M. Salomaa

弘樹 斎藤, Hiroki Saito

Qing-Li Zhu, Lihua Pan

Yuki Kawaguchi, Tetsuo Ohmi

We consider the splitting mechanism of a multiply charged vortex into singly charged vortices in a Bose-Einstein condensate confined in a harmonic potential at zero temperature. The Bogoliubov equations support unstable modes with complex eigenfrequencies (CE modes), which cause the splitting instability without the influence of thermal atoms. The investigation of the excitation spectra shows that the negative-energy (NE) mode plays an important role in the appearance of the CE modes. The configuration of vortices in splitting is determined by the angular momentum of the associated NE mode. This structure has also been confirmed by the numerical simulation of the time-dependent Gross-Pitaevskii equation.

Tomoya Isoshima

Multiply charged vortices have been realized in Bose–Einstein condensates of atomic gases. Theoretically, they are expected to split into singly charged vortices. It is numerically predicted that the split vortices may form a chain structure under certain conditions. This paper addresses conditions required to create and observe the vortex chain structures and a more complicated structure.

Tomoya Isoshima