Skyrmion Excitation in Two-Dimensional Spinor Bose-Einstein Condensate
  We study the properties of coreless vortices(skyrmion) in spinor Bose-Einstein condensate. We find that this excitation is always energetically unstable, it always decays to an uniform spin texture. We obtain the skyrmion energy as a function of its size and position, a key quantity in understanding the decay process. We also point out that the decay rate of a skyrmion with high winding number will be slower. The interaction between skyrmions and other excitation modes are also discussed. 
Hui Zhai, WeiQiang Chen, Zhan Xu, Lee Chang (CASTU, Tsinghua   University, China)