Interlocked knot in spinor Bose-Einstein condensates

The physics of topological defects have been extensively studied by theory and experiment in recent years. Vortex rings especially linking vortex rings are difficult to create and stabilize in experiments. We study a new structure of knot called interlocked knot in the antiferromagnetic spin-1 Bose-Einstein condensate, which has never been studied before. The interlocked knot differs from the conventional knot with linking vortex rings that are connected by a Mobius strip. It cannot be converted to untwisted rings without cutting them. We propose two schemes to generate the interlocked knot in experiments either by using an external magnetic field, or alternatively, by the spin-orbit coupling in spin-1 condensates. Our results open a new perspective for the study of knot and extend the application of experimental technique. (C) 2020 Elsevier Ltd. All rights reserved.