Superconducting qubits Model of transmon qubit adapted from “Theory of superconducting qubits beyond the lumped-element approx-imation,” Phys. Rev. Applied 21, 024030/1-22 (2024). Fluxonium circuit diagram adapted from “Right-sizing fluxonium against charge noise,” Phys. Rev. B 102, 014512/1-5 (2020). At low temperatures, circuits made of superconducting materials can exhibit quantum effects. As a result, these circuits have been recruited for use as qubits. Our group investigates the behavior of superconducting circuits designed to act as qubits, paying special attention to their robustness to noise. Our investigations sometimes start with the phenomenological quantum circuit model that is commonly used in the field. To get more fundamental insights, we sometimes study circuits using the microscopic Bardeen-Cooper-Schrieffer theory of superconductivity,