Blinova Alina, Zamora-Zamora Roberto, Ollikainen Tuomas, Kivioja Markus, Möttönen Mikko, Hall David S
Department of Physics and Astronomy, Amherst College, Amherst, MA, 01002-5000, USA.
Department of Physics, University of Massachusetts Amherst, Amherst, MA, 01003, USA.
Nat Commun. 2023 Aug 29;14(1):5100. doi: 10.1038/s41467-023-40710-2.
Monopoles and vortices are fundamental topological excitations that appear in physical systems spanning enormous scales of size and energy, from the vastness of the early universe to tiny laboratory droplets of nematic liquid crystals and ultracold gases. Although the topologies of vortices and monopoles are distinct from one another, under certain circumstances a monopole can spontaneously and continuously deform into a vortex ring with the curious property that monopoles passing through it are converted into anti-monopoles. However, the observation of such Alice rings has remained a major challenge, due to the scarcity of experimentally accessible monopoles in continuous fields. Here, we present experimental evidence of an Alice ring resulting from the decay of a topological monopole defect in a dilute gaseous Rb Bose-Einstein condensate. Our results, in agreement with detailed first-principles simulations, provide an unprecedented opportunity to explore the unique features of a composite excitation that combines the topological features of both a monopole and a vortex ring.
单极子和涡旋是基本的拓扑激发，出现在跨越巨大尺寸和能量尺度的物理系统中，从早期宇宙的广袤空间到向列型液晶和超冷气体的微小实验室液滴。尽管涡旋和单极子的拓扑结构彼此不同，但在某些情况下，一个单极子可以自发且连续地变形为一个涡旋环，具有奇特的性质，即穿过它的单极子会转变为反单极子。然而，由于在连续场中实验上可获取的单极子稀缺，观察到这种艾丽斯环仍然是一个重大挑战。在这里，我们展示了由稀薄气态铷玻色 - 爱因斯坦凝聚体中的拓扑单极子缺陷衰变产生艾丽斯环的实验证据。我们的结果与详细的第一性原理模拟一致，为探索一种结合了单极子和涡旋环拓扑特征的复合激发的独特特性提供了前所未有的机会。
