Microwave sensing with interacting cold Rydberg atoms

Rydberg atoms have emerged as highly sensitive RF sensors due to their large dipole moments in the microwave regime. By carefully selecting quantum states, they can realize polarization-resolvable self-calibrating isotropic microwave electrometry. Cold-atom-based microwave sensors have recently gained attention for their supression in Doppler shifts and atom-transit-induced dephasing. In addition, despite introducing decoherences, interactions between cold Rydberg atoms bring more possibilities beyond traditional detections, such as leveraging quantum entanglement and avalanche gain for rare-event detections. Here I present our experimental and theoretical efforts for microwave detection and applications in quantum information processing with cold atoms. We demonstrate a full vector electrometry and frequency detection of microwave with a sinlge spectroscopy measurement in a cold atom ensemble and investigate the nonlinear effect and decoherence due to Rydberg interactions in such a system. This paves a path for the microwave control of Rydberg-based quantum information processors. The method can be applied to atomic arrays for better controllability. We also propose signal amplification and information transport schems in atomic arrays and are looking forward to implementing them in experiments.