Predicting dynamics and measuring crosstalk with simultaneous Rabi experiments

Crosstalk is a substantial obstacle impeding the realization of practical many-qubit quantum computers. A noteworthy instance of crosstalk affecting superconducting qubits is drive crosstalk, where microwave drive fields intended for one subsystem also interact with other subsystems, inducing correlated local errors. During this talk, we introduce a novel simultaneous Rabi experiment for characterizing drive crosstalk that is robust to SPAM errors. We fit the parameters for a Hamiltonian describing a two-transmon system with crosstalk and find excellent agreement between theory and experiment. By repeating the characterization protocol for all pairs of qubits in a system, we construct a model for the entire chip and accurately predict crosstalk dynamics for more than two concurrently driven qubits. These results show that drive crosstalk is a correctable problem for NISQ devices. Combining this approach with prior theoretical work that we published paves the way to mitigate the effects of crosstalk via digital circuit precompilation.