Control and readout of a transmon using a compact superconducting resonator

We demonstrate control and readout of a superconducting artificial atom based on a transmon qubit using a compact lumped-element resonator. The resonator consists of a parallel-plate capacitor with a wire geometric inductor. The footprint of the resonators is about 200 × 200 μm2, which is similar to the standard transmon size and one or two orders of magnitude more compact in the occupied area compared to coplanar waveguide resonators. We observe coherent Rabi oscillations and obtain time-domain properties of the transmon. The work opens a door to miniaturize essential components of superconducting circuits and to further scale up quantum systems with superconducting transmons.