arXiv:1406.7056 · Europhysics Letters (EPL)
Stable knots in the trapped Bose-Einstein condensates
Yong-Kai Liu, Shiping Feng, Shi-Jie Yang
Abstract
The knot of spin texture is studied within the two-component Bose-Einstein condensates which are described by the nonlinear Gross-Pitaevskii equations. We start from the non-interacting equations including an axisymmetric harmonic trap to obtain an exact solution, which exhibits a non-trivial topological structure. The spin-texture is a knot with an integral Hopf invariant. The stability of the knot is verified by numerically evolving the nonlinear Gross-Pitaevskii equations along imaginary time.