Physicists observe enigmatic 'Alice Rings' for the first time

"We are the only ones who have been able to create topological monopoles in quantum fields,"  Mikko Möttönen of the monopole Collaboration from Aalto University in Finland explained to ScienceAlert. "After creating them, it took some time for us also to study quantum knots and skyrmions before we had a close look at what happens to the topological monopole right after it has been created," he added.

Only two years after their first observation, the researchers were surprised to discover that monopoles can transform into other types. During their latest study, the scientists observed a topological monopole once again change into something else, resulting in a small opening similar to a gateway to Alice's famed "Wonderland." These structures, known as "Alice Rings," were the result.

"Alice Rings," the researchers explain, are linked to monopoles, which transform into one-sided magnetic poles when they form loops. However, "Alice Rings" have a longer lifespan than typical monopoles, lasting more than 80 milliseconds, which is 20 times longer than "normal."

"From a distance, the Alice Ring just looks like a monopole, but the world takes a different shape when peering through the center of the ring," says David Hall, a physicist from Amherst College in the US.

Passing through a peculiar magnetic loop in a Bose-Einstein condensate (BEC) quantum field can turn everything upside down, just like Alice's "Looking Glass." Any other monopoles that fall through are transformed into their mirror images, causing the ring to flip into its opposite as they pass through. Although the formation of the ring in the decay of a topological monopole has not been observed experimentally by the team, it is exciting progress.

Though the looking-glass

From a practical standpoint, it is difficult to determine how this discovery might be utilized. However, as scientists gain further insight into the unpredictable properties of quantum fields, we can improve our understanding of their complexities and uncover profound insights into the nature of reality.

"Primarily, this creation of 'Alice Rings' is of fundamental importance," Möttönen told ScienceAlert. "It casts light and inspiration to the search of the deepest constituents of the Universe, matter, and information," he added.

You can view the study for yourself in the journal Nature Communications.

Study abstract:

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 87Rb 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.