Fig. 2: Heuristic search of optimal parameters for the five-qubit hardware experiment.

a Accuracy of QSP angle optimization, Eq. (11), using pyqsp⁵⁰. b Upper bound to the infidelity, Eq. (16), as a function of degree d and evolution time Jt. c For each evolution time, the optimal degree d_opt is the degree that minimizes the total error ϵ_total in b.