Illustration of Alice’s ring first observed
Heika Valya/Aalto University
Physicists look through the proverbial mirror, and opposite atoms belong to opposite worlds. For the first time, researchers have created an exotic quantum object called an Alice ring. This object changes its properties when other quantum objects pass through it or are simply seen through it.
Quantum systems, such as ensembles of extremely cold atoms or entire universes, should theoretically contain strange objects called topological defects. Some look like long strings, others are even more bizarre. It is a zero-dimensional point, at the center of which things like magnetic fields are mathematically inexplicable.
Such defects are difficult to create and observe.but Mikko Mottonen PhDs from Aalto University in Finland have studied how to create topological defects that quickly transform into other defects.
To do this, they first placed 250,000 rubidium atoms in a small, airless chamber, then irradiated them with a laser to slow their natural movement and push them to temperatures near absolute zero. Under these conditions, all atoms acted as her one large quantum object. A quantum property called spin made the object susceptible to magnetic fields.
Mottonen says the team used computer simulations and mathematical models We determine how to pattern the direction and strength of the magnetic field in order to twist the atoms until a topological defect appears. This approach was previously used to create defects, called monopoles, which are single-pole, magnet-like particles.
Well, the researchers also observed the fate of the monopole. A few milliseconds later, each monopole they created expanded into an Alice ring with one very strange property.
“This Alice’s ring has a peculiarity. Depending on whether you look at a nearby monopole through the ring or from the side of the ring, its charge will appear different. ,” says Mottonen. Furthermore, computer simulations showed that the charge of the monopole is completely reversed, for example from positive to negative, when the monopole moves through the Allis ring.
Mottonen and colleagues have previously used this method to create topological defects, such as knot-like structures and special spirals called skyrmions, in cryogenic atoms. The next challenge they’re aiming for, he says, is not just to create a monopole and an Alice ring, but to pass one through the other to test their mirror-like functions directly.
Janne Ruostekowski Researchers at the University of Lancaster in the UK said the method they developed was unique and could also make it possible to visualize abstract mathematical theorems. For example, it could provide scientists with a way to investigate the so-called “hairball theorem,” which determines the texture of the field around topological defects.
He says this opens up “unprecedented opportunities” to explore theories in cosmology and high-energy physics that “have so far had no experimental evidence.”
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