Rydberg polaron

A Rydberg polaron is an exotic quasiparticle, created at low temperatures, in which a very large atom contains other ordinary atoms in the space between the nucleus and the electrons.

Bose–Einstein condensates are a state of matter that is produced at temperatures close to absolute zero.

Polarons are induced by using a laser to excite Rydberg atoms contained as impurities in a Bose–Einstein condensate.

As the atoms don't have an electric charge, they only produce a minimal force on the electron.

The excitation was predicted by theorists at Harvard University in 2016[3] and confirmed in 2018 by spectroscopy in an experiment using a strontium Bose–Einstein condensate.

Schematic showing a Rydberg polaron. Strontium atoms (in yellow) fit inside the orbit between the nucleus (in red) and the electron (in blue) of a Rydberg atom.