Designing Crosstalk Robust Gate Sets using Optimal Control

Crosstalk is a detrimental type of unintended correlated noise that harms the fidelity of quantum computations. One particularly harmful category of crosstalk affecting devices based on fixed frequency superconducting qubits is ZZ-crosstalk. We leverage optimal control to design gate sets that are able to suppress ZZ-crosstalk across entire devices during computations. Previous software approaches have demonstrated ZZ-crosstalk suppression within constrained circuit blocks by combining optimal control and scheduling co-optimization. In our work, we achieve complete and scalable crosstalk suppression by coordinating redundant implementations of basis gates differing in their pulse implementation. We evaluate calibration schemes for achieving our gates on hardware. We report the success of our approach by running dynamical simulations of circuits across a suite of benchmark quantum algorithms.