Quantum Control in the Full Hyperfine Ground Manifold of Cesium

Abstract

Cold atomic spins are a great platform for developing and testing control and measurement techniques. This thesis presents experimental investigations into quantum control and measurement using laser cooled cesium atoms. On the control side, we present an experimental realization of a protocol to achieve full controllability of the entire hyperfine ground manifold of cesium. In particular, we demonstrate the ability to map between arbitrary states with fidelity greater than 0.99, using a combination of static, radio frequency, and microwave magnetic fields. On the measurement side, we present an experimental realization of quantum state tomography. The tomography protocol begins by measuring expectation values of an informationally complete set of observables using a weak optical probe in combination with dynamical control. The measurement record is processed using two different state estimation algorithms, allowing us to estimate a quantum state with fidelity greater than 0.9.