Characterizing coherent errors using matrix-element amplification
Abstract
Precision quantum estimation in the presence of noise remains a serious practical challenge for calibrating state-of-the-art quantum processors. Noise processes, such as flux noise in superconducting qubits, introduce fluctuations that obscure the true values of system parameters and hinder coherent amplification. We demonstrate a novel characterization technique that enables precise estimation of select unitary parameters for two-qubit gates by applying dynamical decoupling to suppress low-frequency noise. Our method exhibits order-of-magnitude improvements in parameter precision, is efficient in the number of experiments required, adapts to a variety of target two-qubit gates, and is robust to implementation imperfections.
