A miniature universe shows particles may emerge out of empty space

A primary-of-its-kind experiment simulating the cosmos with ultracold potassium atoms means that in a curved, increasing universe pairs of particles pop up out of empty house

By Karmela Padavic-Callaghan

An analogue of a tiny, increasing universe has been created out of extraordinarily chilly potassium atoms. It might be used to assist us perceive cosmic phenomena which might be exceedingly tough to instantly detect, resembling pairs of particles that could be created out of empty house because the universe expands.

Markus Oberthaler at Heidelberg College in Germany and his colleagues cooled greater than 20,000 potassium atoms in a vacuum, utilizing lasers to gradual them down and decrease their temperature to about 60 nanokelvin, or 60 billionths of a level kelvin above absolute zero.

At this temperature, the atoms shaped a cloud in regards to the width of a human hair and, as a substitute of freezing, they turned a quantum, fluid-like part of matter known as a Bose-Einstein condensate. Atoms on this part could be managed by shining mild on them – utilizing a tiny projector, the researchers exactly set the atoms’ density, association in house and the forces they exert on one another.

By altering these properties, the crew made the atoms observe an equation known as a space-time metric, which, in an precise, full-scale universe, determines how curved it’s, how briskly mild travels and the way a lot mild should bend close to very huge objects. That is the primary experiment that has used chilly atoms to simulate a curved and increasing universe, says Oberthaler.

When the researchers used their projector to make atoms mimic an increasing universe, the atoms moved in precisely the sort of ripple sample that might be anticipated if pairs of particles had been popping into existence – a phenomenon known as particle pair manufacturing. The researchers say this means that the particle pairs could be produced in an increasing universe, like our personal.

Alessio Celi on the Autonomous College of Barcelona in Spain says that the brand new experiment is a really exact playground for placing collectively quantum results and gravity. Physicists don’t fairly understand how the 2 mix within the universe we reside in, however experiments with ultracold atoms could allow them to check out some concepts, they usually may encourage new targets for observations in our a lot bigger and extra complicated cosmos, he says.

Stefan Floerchinger on the College of Jena in Germany, who was a part of the analysis crew, says that future experiments with the identical system may result in a greater understanding of quantum properties of our universe.

Journal reference: Nature, DOI: 10.1038/s41586-022-05313-9