Exploring Design-Dependent Charge-Noise in Charge-Sensitive Transmons

Superconducting qubits are a versatile platform for quantum computation, offering precise control of microwave excitations, design flexibility, and strong coupling. However, their coupling to the electromagnetic environment makes superconducting qubits susceptible to various noises in the solid-state environment. Recently, charge-sensitive transmon qubits have been used to probe the dynamics of offset charge noise and decoherence mechanisms induced by excess quasi-particles. We aim to investigate offset charge noise that could arise from material defects, and how it varies with material choices and device geometry. Using multiple transmons, we can identify potential spatiotemporal correlations in the offset charge noise. Additionally, we will study quasiparticle tunneling dynamics in different qubit designs, e.g. floating and grounded transmons, superconducting island geometry, and ground plane configurations. We will present our experimental efforts to systematically characterize charge-sensitive transmon arrays with these design variations. Further, we will discuss plans for future studies of charge-noise induced errors in interacting multi-qubit devices, and applications for phonon detection.