Progress towards a hybrid atom-superconductor interface*

 

Quantum information processing faces the challenge of developing a scalable next-generation hardware. Superconducting circuits are a promising qubit source due to their fast gate operations via high-fidelity microwave control but have limited coherence time and no native optical connections couplings for long-distance networking. Neutral atoms have the potential for coherent quantum information storage, high-fidelity gate operations, possess microwave and optical transitions, can be trapped in individually addressable arrays but have slow gate operations.To overcome the limitations of each qubit type, this hybrid approach combines two technologies to harness their individual strengths. Rydberg atoms provide long lifetimes at low temperature and strong interactions with external DC and microwave fields. Thus we aim to realise a superconductor-atom interface with applications for long distance entanglement of atomic ensembles in a protocol robust to thermal excitations.

Progress has been made designing and characterising superconducting coplanar waveguide resonators in a cryogenic system at 4 K. To overcome working in a quasi-particle limited regime the quality factor of the resonators is maximised by engineering the device geometry and material properties. We have modelled the multi-level atom where the inclusion of the cavity cooling scheme efficiently removes thermal excitations from the mode to improve the visibility of the strong coupling signature for the cavity QED system.