Designing and driving superconducting qutrit processors

Computations with quantum three-level systems (qutrits) offer potential advantages over those with qubits, and they are available on current superconducting quantum processors with very little additional overhead. Despite recent progress in improving superconducting qutrit processors, research into optimizing qutrit gate fidelities and coherence times still lags behind similar research for two-level systems. In this talk, we discuss ongoing efforts to understand and mitigate coherent and incoherent errors specific to quantum information processing with transmon qutrits. First, we present an experimental investigation into scaling of higher-level coherence times with circuit parameters such as E_J/E_C and surface participation ratios. Second, we apply analytical perturbative methods to address coherent errors arising from simultaneous driving of two transition frequencies. By studying and mitigating errors specific to qutrit processors, this research aims to realize high-fidelity qutrit control.