Ultracold polar molecules are an exciting platform for quantum science and technology. The combination of rich internal structure of vibration and rotation, controllable long-range dipolar interactions and strong coupling to applied electric and microwave fields has inspired many applications. These include quantum simulation of strongly interacting many-body systems, the study of quantum magnetism, quantum metrology and molecular clocks, quantum computation, precision tests of fundamental physics and the exploration of ultracold chemistry. Many of these applications require full quantum control of both the internal and motional degrees of freedom of the molecule at the single particle level.
In Durham, we study ultracold ground-state RbCs molecules formed by associating Rb and Cs atoms using a combination of magnetoassociation and stimulated Raman adiabatic passage. This talk will report our work on the development of full quantum control of the molecules. Specifically, I will report on experiments that produce single molecules in optical tweezers starting from a single Rb and a single Cs atom [6]. Using this platform, we prepare the molecules in the motional ground state of the trap and can perform addressing and detection of single molecules. Using mid-sequence detection of formation errors, we demonstrate rearrangement to produce small defect-free arrays. By transferring the molecules into magic-wavelength tweezers, we can prepare long-lived rotational coherences that support spin-exchange interactions between molecules, enabling the preparation of maximally entangled Bell states with high fidelity. I will show that the magic-wavelength trap also supports coherent multi-state superpositions opening up the prospect of engineering synthetic dimensions in the molecule and more exotic spin mappings.
Finally, as an outlook I will briefly describe the development of a quantum gas microscope for molecules and report our recent achievement of spin-resolved and site-resolved detection of single molecules.