New quasiparticle created in cold quantum matter

All over nature, elementary particles interact with their environment. Electrons in a solid interact with their surroundings, which is essential for modern semi-conductor technology. Even elementary particles acquire their mass by the interplay with the renowned Higgs boson. Now, researchers at the Department of Physics and Astronomy, Aarhus University have developed a new approach to study these phenomena.

They insert impurities into ultracold quantum matter!

By cooling a small cloud of atoms close to absolute zero temperature a powerful scientific playground emerges – the Bose-Einstein-condensate – which provides an unmatched opportunity to study physics at the quantum level. By immersing impurity atoms into this quantum gas, the general scenario of a particle interacting with its environment can be studied in unprecedented detail.

Observing the interplay between an impurity and the condensate experimentally, the researchers found that the impurity disturbed its quantum surroundings to form a quasiparticle called a Bose polaron. This effect has also been observed in the familiar setting of an electron in a solid, but never in this type of versatile and pure quantum environment.

This novel experiment opens up exciting possibilities to mimic a number of other physical systems as well as to study entirely new physics. In the near future, this could lead to an increased understanding of superconductors or even provide knowledge as to why fundamental particles have mass.

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A link to the Physical Review Letters paper is here.

Physical Review Letters deem this discovery important enough to have asked the French researcher Frédéric Chevy to write a viewpoint article explaining some more aspects of the discovery.