Observation of electric field induced superradiance slowdown in ultracold Rydberg atomic gases

Atoms excited to electronically high-lying Rydberg states decay to low-energy states through spontaneous emission processes. We investigate the impact of a static electric field on the superradiant emission process between Rydberg |60 D 5/2 〉 and |61 P 3/2 〉 states in an ultracold Cesium Rydberg atom ensemble. We report experimental observations of a significant slowdown in superradiance upon applying an electric field. To understand the slowing down of superradiance, we employ a master equation in which Stark effects and collective decay are taken into account. We solve the master equation with the discrete truncated Wigner approximation (DTWA) method. Our numerical simulations demonstrate that superradiance decoherence is caused by the Stark shifts of the Rydberg level. Our theoretical simulations qualitatively match the experimental observations. Our work provides new insights into controlling quantum critical behaviors, with implications for quantum many-body dynamics, and the study of quantum phase transitions.