Independent state and measurement characterization for quantum computers

Correctly characterizing state preparation and measurement (SPAM) processes is a necessary step towards building reliable quantum processing units (QPUs). In this work, we discuss the subtleties behind separately measuring SPAM errors. We propose protocol that can estimate errors, in case where gates are ideal. imperfect, derive bounds on estimated error rates, based gate measures which be independently of processes. Our method shows gauge ambiguity operations resolved, by assuming there exists one qubit whose initial uncorrelated with other qubits QPU. test publicly available five-qubit QPU demonstrate its validity comparing our results simulations.