Independent state and measurement characterization for quantum computers

Autor: Junan Lin, Joel J. Wallman, Ian Hincks, Raymond Laflamme
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Physical Review Research, Vol 3, Iss 3, p 033285 (2021)
Druh dokumentu: article
ISSN: 2643-1564
DOI: 10.1103/PhysRevResearch.3.033285
Popis: 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 a protocol that can separately estimate SPAM errors, in the case where quantum gates are ideal. In the case where the quantum gates are imperfect, we derive bounds on the estimated SPAM error rates, based on gate error measures, which can be estimated independently of SPAM processes. Our method shows that the gauge ambiguity in characterizing SPAM operations can be resolved by assuming that there exists one qubit whose initial state is uncorrelated with other qubits in a QPU. We test the protocol on a publicly available five-qubit QPU and demonstrate its validity by comparing our results with simulations.
Databáze: Directory of Open Access Journals