Abstract
Estimating the features of noise is the first step in a chain of protocols that will someday lead to fault tolerant quantum computers. The randomized benchmarking (RB) protocol is designed with this exact mindset, estimating the average strength of noise in a quantum processor with relative ease in practice. However, RB, along with most other benchmarking and characterization methods, is limited in scope because it assumes that the noise is temporally uncorrelated (Markovian), which is increasingly evident not to be the case. Here, we combine the RB protocol with a recent framework describing non-Markovian quantum phenomena to derive a general analytical expression of the average sequence fidelity (ASF) for non-Markovian RB with the Clifford group. We show that one can identify non-Markovian features of the noise directly from the ASF through its deviations from the Markovian case, proposing a set of methods to collectively estimate these deviations, non-Markovian memory time-scales, and diagnose (in)coherence of non-Markovian noise in an RB experiment. Finally, we demonstrate the efficacy of our proposal by means of several proof-of-principle examples. Our methods are directly implementable and pave the pathway to better understanding correlated noise in quantum processors.
Highlights
The biggest challenge faced in any quantum computation can almost unequivocally be said to be the presence of errors
The approach known as randomized benchmarking (RB) [1,2,3,4,5] has become the gold standard to certify the performance of gate sets and characterize the noise in computations involving these sets
IV we present our main result within Eq (7) and discuss some of its properties and consequences, including containment of the Markovian case, the issue of initial correlations and the impact of state preparation and measurement (SPAM) errors
Summary
The biggest challenge faced in any quantum computation can almost unequivocally be said to be the presence of errors. We derive an analytical expression for the ASF of a RB experiment with the Clifford group under non-Markovian gate-independent noise This allows the study of the behavior of ASF decays due to nonMarkovianity, and of deviations from exponential decays, given a model for the noise. Just as in the standard Markovian case, the relevance of RB lies in its simplicity, as it allows non-Markovian features to be analyzed and quantified from experiment with relative ease Overcoming these restrictions can be a focus of future research towards a practical and more complete characterization of temporally correlated noise. IX with an overview of our results and a perspective for future work
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
