Polariton noise in Rydberg electrometry*

The establishment of metrics and control of fundamental noise sources in electromagnetic field sensing with atoms is a long-standing goal in quantum science and technology that is of fundamental and practical importance. To date, fundamental noise sources limiting the sensitivity of Rydberg atom electric field sensing in vapors have remained elusive. Here we report on the observation of a new limiting noise source found to arise from many-body Rydberg polariton (slow-light) propagation through Rydberg-EIT media in atomic vapors. The Rydberg-mediated optical noise is found to be sub-thermal at short correlation times. We demonstrate noise control and reduction under certain operating conditions. Our work sheds light on many-body Rydberg polariton physics in thermal vapors and paves a way towards new fundamental sensitivity limits in Rydberg electrometry.