Smart experiment on simple atoms improves understanding of dark matter

An experiment to test a popular theory of dark energy has failed to highlight new forces, which imposes strong constraints on related theories.

Dark energy is the name given to an unknown force that causes the expansion of the universe at an accelerated rate.

Some physicists propose that dark energy is a "fifth" force acting on matter, beyond the four forces already known – gravitational, electromagnetic, and strong and weak forces.

However, researchers believe that this fifth force can be "masked" or "hidden" for large objects such as planets or weights on Earth, making it difficult to detect.

Researchers from Imperial College London and the University of Nottingham have now tested the possibility of this fifth force acting on a single atom and found no evidence of this in their most recent experiment.

This could negate the popular theories of black energy that alter the theory of gravity and leave less room for the search for the fifth elusive force.

Find the fifth force

The experiment, conducted at Imperial College London and analyzed by theorists at the University of Nottingham, is reported in Letters of physical examination.

Professor Ed Copeland, Center for Astronomy and Particle Physics at the University of Nottingham, said: "This experiment, which links atomic physics to cosmology, has allowed us to exclude a wide range of models that have been proposed to explain the nature of the phenomenon. dark energy, and will allow us to constrain many more models of dark energy. "

The experiment tested on the theories of dark energy according to which the fifth force is comparatively lower when there is more material around – in contrast to the behavior of gravity.

It would mean that he is strong in a space-like vacuum, but weak when there is a lot of material around. Therefore, experiments using two large weights would mean that the force becomes too weak to be measured.

Experiment with one atom

The researchers instead tested a larger weight with an incredibly small weight – a single atom – where strength should have been observed if it existed.

The team used an atomic interferometer to check if there were additional forces that could be the fifth force acting on an atom. A metal sphere the size of a marble was placed in a vacuum chamber and the atoms were left in free fall inside the chamber.

The theory is this: if there is a fifth force acting between the sphere and the atom, the path of the atom will deviate slightly as the sphere passes, which will change the path of the falling atom. However, no such force has been found.

Professor Ed Hinds, of the Imperial Physics Department, said: "It is very exciting to be able to discover something about the evolution of the universe using a tabletop experience in a sub -sol of London. "

###

Reference: "Experience in Detecting Black Energy Forces by Atomic Interferometry" by D. O. Sabulsky, I. Dutta, E. A. Hinds, B. Elder, C. Burrage, and Edmund J. Copeland, August 6, 2019, Letters of physical examination. DOI: 10.1103 / PhysRevLett.123.061102