This thesis is focused on development of theoretical and experimental techniques for the realisation of a hybrid interface between a Rydberg atom and a micro-fabricated superconducting resonator. This work is motivated bythe potential to achieve long-range interactions between atomic qubits and efficient microwave to optical quantum transduction for quantum networking applications. We present a theoretical study of the feasibility for observing single-atom strong coupling for a Rydberg atom interacting with a superconducting resonator at 4 K. We demonstrate finite temperature effects place strict requirements on a cavity quality factor of Q ≥ 104. By exploiting this coupling theimplementation of a cavity cooling scheme efficiently reduces the thermal microwave mode occupation towards the ground state, enabling observation of coherent vacuum Rabi oscillations even at 4 K for realistic experimentalparameters. Experimental developments presented in this thesis include design, characterisation and fabrication of NbN resonators, with demonstration of a maximum loaded Q = 0.83 ×104 at 3 K which reduces at higher temperatures. Despite optimising the geometric design of the NbN coplanar waveguide (CPW) resonator for operation in a quasi-particle limited environment, characterisation of the samples determined that the quality factor is currently limited by the∼11.6 K critical temperature of the superconducting material. We further present progress towards cryogenic single-atom trapping, including integration of moveable atomic tweezers. We demonstrate coherent information encoded in the atomic state is persevered as the atom is transported over a distance of 83 µm in 2 ms, and integration of high NA optics for single atom trapping and imaging into a low-vibration cryostat. We demonstrate atom transport to the cryogenic environment, achieving a base temperature of 5.7 K without shielding and enhanced vacuum lifetime due to cryopumping.
Date of Award | 22 Sept 2022 |
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Original language | English |
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Awarding Institution | - University Of Strathclyde
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Sponsors | University of Strathclyde |
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Supervisor | Jonathan Pritchard (Supervisor) & Erling Riis (Supervisor) |
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