title: Spontaneous splitting of a quadruply charged vortex.
abstract: We studied the splitting instability of a quadruply charged vortex both experimentally and theoretically. The density defect, which is a signature of the vortex core, is experimentally observed to deform into a linear shape. The deformed defect is theoretically confirmed to be an array of four linearly aligned singly charged vortices. The array of vortices rotates and precesses simultaneously with different angular velocities. The initial state of the system is not rotationally symmetric, which enables spontaneous splitting without external perturbations.
authors.affiliation: Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Isoshima
authors.forename: M
authors.initials: M
authors.lastname: Okano
authors.forename: H
authors.initials: H
authors.lastname: Yasuda
authors.forename: K
authors.initials: K
authors.lastname: Kasa
authors.forename: J A M
authors.initials: JA
authors.lastname: Huhtamäki
authors.forename: M
authors.initials: M
authors.lastname: Kumakura
authors.forename: Y
authors.initials: Y
authors.lastname: Takahashi