Utilizing controllable collective light-atom interactions, I explore the properties of large ensembles of cold Rb-87 atoms interacting with an optical cavity for producing collective light emission and for generating entangled atomic states.
In one set of experiments, I demonstrate a unique atomic magnetometer based on superradiant Raman lasing transitions between hyper fine ground states of a large ensemble of atoms. This sensor can operate in a continuous broadband or narrowband mode based on evolution of the atomic coherence in the dark. I also discuss the fundamental sensitivity of this type of detector.
In a second set of experiments, I present studies of the synchronization mechanism between two ensembles undergoing steady state superradiance within the same optical cavity. I explore the behavior of the two oscillators in response to the introduction of controllable phase errors between them in both transient and steady state experiments. This work may inform future studies of quantum phase transitions in open quantum systems.
Finally, I discuss progress in another related experimental direction:
cavity-aided non-demolition measurements of the collective atomic spin state of an ensemble of atoms. The coherence-preserving collective measurements presented may one day have the capacity to reduce the impact of quantum noise in state-of-the-art precision measurements like clocks and acceleration sensors based on atoms. By improving our apparatus, we expect to significantly improve on our previous factor of 10 improvement over the standard quantum limit on quantum phase estimation for unentangled atoms.