Researchers report the creation of Rydberg polarons in a Bose gas

What is inside an atom between the nucleus and the electron? Usually there is nothing, but why could there not be other particles too? If the electron orbits the nucleus at a great distance, there is plenty of space in between for other atoms. A “giant atom” could be created, filled with ordinary atoms. All these atoms form a weak bond, creating a new, exotic state of matter at cold temperatures, referred to as Rydberg polarons.