Microwave spectroscopy of closed-loop superconducting resonators*

The advent of circuit quantum electrodynamics opened up a new venue spanning the fields of synthetic matter, quantum information, and quantum sensors, just to name a few. A foundational element of these applications relies on high-quality factor superconducting resonators based on the Fabry-Perot-inspired geometries. The range of accessible physics can be expanded by considering closed-loop resonator geometries with potential applications ranging from the uniform coupling of scalable qubit networks to probes sensitive to chiral materials. Here, we report on characterization of lithographically defined superconducting ring resonators and present the initial microwave spectroscopy results showing the rich phenomenology of these geometries.