Mitigating errors in single and two-qubit gates

Superconducting qubits offer long coherence times relative to their operation speed, making them promising candidates for quantum computation. However, trade-offs in their coupling to other qubits and the environment, along with parameter fluctuations in the environment and the control, lead to reduced gate fidelities. In this presentation, I will discuss our strategies for implementing high-fidelity single- and two-qubit gates for superconducting qubits. For single-qubit gates, I will introduce Fourier-series-based pulse shaping, which enhances robustness against amplitude and frequency errors, outperforming standard DRAG gates. For two-qubit operations, I will demonstrate how carefully chosen flux-pulse parameterizations in combination with efficient closed-loop optimal control schemes enable gate fidelities reaching 99.9%. A fundamental challenge in superconducting qubits is that control and readout require coupling to the environment, which inevitably degrades coherence. To address this, I will present a control scheme for fluxonium qubits based on sub-harmonic driving, as well as a novel multi-mode qubit design - the P-mon - that effectively mitigates Purcell-induced decoherence. These advancements contribute to improving the control of superconducting qubits, bringing us closer to scalable quantum computing.