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New interactions seen in an ultracold gas

Cold atom experiments have revealed a novel interaction between pairs of particles that is mediated by a surrounding quantum gas. Georg Bruun describes the discovery in Nature News and Views.

[Translate to English:] Figur: Fysikerne observerede en tiltrækkende vekselvirkning mellem Cs-atomer, der blev overført af en omgivende gas af Li-atomer.
[Translate to English:] Figur: Fysikerne observerede en tiltrækkende vekselvirkning mellem Cs-atomer, der blev overført af en omgivende gas af Li-atomer.

Mediated interactions play a key role in modern physics. For instance, the fundamental interactions between elemen­tary particles are mediated by gauge bosons such as photons. Also, the attraction between elec­trons that leads to superconductivity in met­als arises from the exchange of vibrations in the surrounding crystal lattice. Now, the first observation of a mediated interaction in an atomic gas has been reported. Given that atomic gases are powerful quantum simulators, this paves the way for a detailed study of the properties of mediated interactions in regimes never realized before.

The article in Nature News and Views can be found here: https://www.nature.com/articles/d41586-019-00988-z