Decay of multiply charged vortices at nonzero temperatures

摘要

Inspired by a recent experiment (Ryu 2007 et al Phys. Rev. Lett. 99 260401), we study the instability of multiply charged vortices in the presence of thermal atoms. We find various scenarios of the splitting of such vortices. The onset of the decay of a vortex is always preceded by an increase in the number of thermal (uncondensed) atoms in the system and manifests itself by the sudden rise of the amplitude of the oscillations of the quadrupole moment. Our calculations show that the decay time gets shorter when the multiplicity of a vortex becomes higher.