Long-lived circular Rydberg states of laser-cooled rubidium atoms in a cryostat

This work demonstrates the preparation of circular Rydberg atoms out of a gas of laser-cooled Rubidium atoms. The circular atoms are prepared within a cryogenic environment that keeps the microwave blackbody radiation as low as 11K, making the measured lifetime of the Rydberg atoms higher than the usual Rydberg levels.