Long-lived Rydberg atoms prepared in a cold atom gas
The performance of quantum technologies significantly depends on the duration over which the apparatus can be run. Rydberg-based quantum technologies, in particular, already rely on the particularly long lifetime of Rydberg atoms, in conjunction with the strength of their mutual interactions. They could see their performances significantly increase by using long-lived circular Rydberg levels: At very low temperature, the latter can live orders of magnitude longer than commonly used Rydberg levels.
The work by the LKB team, recently published in Phys. Rev. Research  within the framework of PASQuanS, demonstrates the first preparation of circular Rydberg atoms out of a gas of laser-cooled atoms. The circular atoms are prepared within a cryogenic environment that keeps the microwave blackbody radiation to as low as 11K, making the measured lifetime of the Rydberg atoms as high as 3.7ms, more than an order of magnitude longer that the commonly used low-orbital-angular-momentum Rydberg levels. It opens the route towards the use of circular Rydberg atoms for the realisation of, e.g., quantum simulations of spin systems over unprecedented timescales.
Reference: T. Cantat-Moltrecht, R. Cortiñas et al., Phys. Rev. Research 2, 022032(R) (2020)