According to scientist interviewed reported be LiveScience.com. Link below for full article

“Physicists have achieved a phenomenon known as subradiance, in which atoms linger in an excited state, in a dense cloud of atoms for the first time. 

Harnessing subradiance could allow scientists to create reliable, long-lived quantum networks from clouds of atoms, the physicists reported in a new study.”  

https://www.livescience.com/physicists-harness-atomic-dark-state.html

https://www.livescience.com/physicists-harness-atomic-dark-state.html