Scientists use a quantum state of matter to simulate the early universe’s expansion

The scientists said their spacetime simulation "agrees very well with theory."
Chris Young
Big Bang representation
Big Bang representation


A team of physicists used a "quantum field simulator" to simulate a tiny expanding universe made out of ultracold atoms, a report from VICE reveals.

The scientists conducted the experiment to simulate the early rapid expansion of the universe following the Big Bang. Their work could lead to accurate representations of the universe in future experiments, allowing for the testing of countless models of the early evolution of the cosmos.

Simulating spacetime

The researchers, who outlined their findings in a paper in the journal Nature, explained that they were able to simulate different curvatures in spacetime that could have had vast implications for the evolution of the early universe. The key breakthrough of the experiment was that it allowed scientists to pause their system for closer inspection at different points of expansion.

Though the experiment isn't a fully accurate simulation of the early universe, it provides a rough approximation of some of the mechanisms that may have governed spacetime and particle production shortly after the Big Bang. Essentially, they were able to show estimations of how an accelerated universe, a decelerated universe, and a constantly expanding universe can all produce particles in different ways.

In order to carry out their experiment, the scientists cooled roughly 20,000 potassium-39 atoms down to temperatures just above absolute zero (approximately -400°F). At these temperatures, the atoms form a Bose–Einstein condensate, a state of matter that allows scientists to simulate the conditions of the early universe, of black holes, and of other cosmic phenomena.

The condensate used for the experiment was a superfluid, meaning it has no viscosity. The team of researchers ran sound waves through the condensate to represent light shining through the universe and simulate different theories of cosmic inflation and different types of spacetime curvature.

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Spacetime simulation "agrees very well with theory"

The scientists found that their simulation matched theoretical predictions for different spacetime curvatures, which validated their methodology. Their work is still in the early stages though, and it doesn't confirm any specific models at this time. Instead, it paves the way for future experiments using the same methodology that could one day hopefully carry out one-to-one comparisons of different theories.

In an interview with VICE, Nikolas Liebster, an experimental physicist at Heidelberg University, Germany, and co-author of the study, said "for these specific assumptions for this model system, it agrees very well with theory, and now we can ask questions that go beyond what the current theory can answer."

Ultimately, the researchers understand that we're still a long way from understanding and accurately simulating the earliest stages of the universe. Still, their work brings the scientific community an important step closer to carrying out one-to-one simulations of some of the most important mechanisms that shaped the cosmos we know today.

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