hopfion

plural hopfions

1. mathematicsA knot in a three-dimensional continuous unit vector field that cannot be unknotted without cutting

   Importantly, we find that the hopfion can be stabilized in a simple parabolic trap, without the need for trap rotation or inhomogeneous interactions.

   2015, R.N. Bisset, Wenlong Wang, C. Ticknor, R. Carretero-Gonzalez, D.J. Frantzeskakis, L.A. Collins, P.G. Kevrekidis, “Robust Vortex Lines, Vortex Rings and Hopfions in 3D Bose-Einstein Condensates”, in arXiv