title: Estimating the Coherence of Noise in Quantum Control of a Solid-State Qubit.
abstract: To exploit a given physical system for quantum information processing, it is critical to understand the different types of noise affecting quantum control. Distinguishing coherent and incoherent errors is extremely useful as they can be reduced in different ways. Coherent errors are generally easier to reduce at the hardware level, e.g., by improving calibration, whereas some sources of incoherent errors, e.g., T_{2}^{*} processes, can be reduced by engineering robust pulses. In this work, we illustrate how purity benchmarking and randomized benchmarking can be used together to distinguish between coherent and incoherent errors and to quantify the reduction in both of them due to using optimal control pulses and accounting for the transfer function in an electron spin resonance system. We also prove that purity benchmarking provides bounds on the optimal fidelity and diamond norm that can be achieved by correcting the coherent errors through improving calibration.
authors.affiliation: Institute for Quantum Computing, Waterloo, Ontario N2L 3G1, Canada.|Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Guanru
authors.initials: G
authors.lastname: Feng
authors.affiliation: Institute for Quantum Computing, Waterloo, Ontario N2L 3G1, Canada.|Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Joel J
authors.initials: JJ
authors.lastname: Wallman
authors.affiliation: Institute for Quantum Computing, Waterloo, Ontario N2L 3G1, Canada.|Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Brandon
authors.initials: B
authors.lastname: Buonacorsi
authors.affiliation: Institute for Quantum Computing, Waterloo, Ontario N2L 3G1, Canada.|Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Franklin H
authors.initials: FH
authors.lastname: Cho
authors.affiliation: Institute for Quantum Computing, Waterloo, Ontario N2L 3G1, Canada.|Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.|Natural Science Research Institute, Korea Advanced Institute of Science and Technology, Daejon 34141, South Korea.
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Park
authors.affiliation: Institute for Quantum Computing, Waterloo, Ontario N2L 3G1, Canada.|Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.|Department of Physics, Tsinghua University, Beijing 100084, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Xin
authors.affiliation: Institute for Quantum Computing, Waterloo, Ontario N2L 3G1, Canada.|Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Dawei
authors.initials: D
authors.lastname: Lu
authors.affiliation: Institute for Quantum Computing, Waterloo, Ontario N2L 3G1, Canada.|Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.|Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Baugh
authors.affiliation: Institute for Quantum Computing, Waterloo, Ontario N2L 3G1, Canada.|Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.|Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2J 2W9, Canada.|Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada.
authors.forename: Raymond
authors.initials: R
authors.lastname: Laflamme