Europhysics Letters (EPL)
Knotted vortex lines in spin-1 Bose-Einstein condensates
J.-Q. Liang, Xiaochen Liu, Yulong Duan
Abstract
Knotted vortex lines in the spin-1 Bose-Einstein condensates are studied. The Faddeev-Niemi model is considered, and it is found that naturally there exist topological vortex line structures in the condensates. We focus on the knotted vortex lines and examine their Faddeev-Niemi knot quantum number. It is shown that the Faddeev-Niemi number is identical to the sum of all the (self-)linking numbers of the knots family and is preserved during the branching processes of vortex lines.