Abstract
We experimentally study the dynamics of quantum knots in a uniform magnetic field in spin-1 Bose-Einstein condensates. The knot is created in the polar magnetic phase, which rapidly undergoes a transition toward the ferromagnetic phase in the presence of the knot. The magnetic order becomes scrambled as the system evolves, and the knot disappears. Strikingly, over long evolution times, the knot decays into a polar-core spin vortex, which is a member of a class of singular SO(3) vortices. The polar-core spin vortex is stable with an observed lifetime comparable to that of the condensate itself. The structure is similar to that predicted to appear in the evolution of an isolated monopole defect, suggesting a possible universality in the observed topological transition.
| Original language | English |
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| Article number | 163003 |
| Journal | Physical Review Letters |
| Volume | 123 |
| Issue number | 16 |
| DOIs | |
| Publication status | Published - 16 Oct 2019 |
| MoE publication type | A1 Journal article-refereed |
Funding
We acknowledge funding by the Academy of Finland through its Centre of Excellence Program (Grant No. 312300), by the European Research Council under Consolidator Grant No. 681311 (QUESS), by the Emil Aaltonen Foundation, and the NSF (Grants No. PHY-1519174 and No. PHY-1806318). CSC-IT Center for Science Ltd. (Project No. ay2090) and Aalto Science-IT project are acknowledged for computational resources.