A Hybrid Quantum System of Ultracold Polar Molecules and Rydberg Atoms

Abstract

Hybrid quantum systems aim to leverage the strengths of different platforms to advance quantum science. This thesis presents the development of a hybrid system of ultracold molecules and Rydberg atoms. We assemble individually trapped 87Rb133Cs molecules and interface them with 87Rb Rydberg atoms. This platform is a foundation for applications that seek to exploit the rich internal structure of molecules and the strong interactions of Rydberg atoms.

We introduce a new method for assembling weakly bound molecules in which optical tweezers are used to associate pairs of atoms. We compare this method to the well established technique of magnetoassociation and find that their efficiencies are comparable. We transfer arrays of up to eight weakly bound molecules to their rovibrational and hyperfine ground state. The overall efficiency of the formation and transfer process is 48(2)%.

We develop a toolbox of techniques for the control and readout of these molecules. We demonstrate global microwave control of multiple rotational states and use auxiliary tweezers to implement site-resolved addressing and state control. We show how the internal state of molecules can be mapped onto the position of atoms and use this capability to readout multiple rotational states in a single experimental run. Further, using a scheme for the mid-sequence detection of molecule-formation errors, we perform rearrangement of assembled molecules to prepare small defect-free arrays.

We study long range interactions between Rb atoms and RbCs molecules. To engineer these interactions, we prepare the atoms in highly excited Rydberg states and use species-specific tweezers to precisely control the separation between particles. We demonstrate blockade of Rydberg excitation due to these interactions for sub-micrometre atom-molecule separations. The development of this hybrid platform opens up prospects for transferring quantum information between individually trapped molecules using Rydberg atoms.