@article{parks_carignan-dugas_gustafson_meurice_dreher_2024, title={Applying the noiseless extrapolation error mitigation protocol to calculate real-time quantum field theory scattering phase shifts}, volume={109}, ISSN={["2470-0029"]}, DOI={10.1103/PhysRevD.109.014505}, abstractNote={Real-time scattering calculations on a noisy intermediate scale quantum (NISQ) quantum computer are disrupted by errors that accumulate throughout the circuits. To improve the accuracy of such physics simulations, one can supplement the application circuits with a recent error mitigation strategy known as noiseless output extrapolation (NOX). We tested these error mitigation protocols on a transverse field Ising model and improved upon previous phase shift calculations. Our proof-of-concept 4-qubit application circuits were run on several IBM quantum computing hardware architectures. We introduce metrics that show between 22% and 73% error reduction for circuit depths ranging from 13 to 37 hard cycles, confirming that the NOX technique applies to circuits with a broad range of failure rates. We also observed an approximate 28% improvement in the accuracy of the time delay calculation of the scattering phase shift. These observations on different cloud-accessible devices confirm that NOX improves performance even when circuits are executed in substantially time-separated batches. Finally, we provide a heuristic method to obtain systematic error bars on the mitigated results, compare them with empirical errors and discuss their effects on phase shift estimates.}, number={1}, journal={PHYSICAL REVIEW D}, author={Parks, Zachary and Carignan-Dugas, Arnaud and Gustafson, Erik and Meurice, Yannick and Dreher, Patrick}, year={2024}, month={Jan} }
 @article{yeter-aydeniz_parks_thekkiniyedath_gustafson_kemper_pooser_meurice_dreher_2023, title={Measuring qubit stability in a gate-based NISQ hardware processor}, volume={22}, ISSN={["1573-1332"]}, DOI={10.1007/s11128-023-03826-4}, abstractNote={Some of the most problematic issues that limit the implementation of applications on Noisy Intermediate Scale Quantum (NISQ) machines are the adverse impacts of both incoherent and coherent errors. We conducted an in-depth study of coherent errors on a quantum hardware platform using a transverse field Ising model Hamiltonian as a sample user application. We report here on the results from these computations using several error mitigation protocols that profile these errors and provide an indication of the hardware qubit stability. Through a detailed set of measurements we identify inter-day and intra-day qubit calibration drift and the impacts of quantum circuit placement on groups of qubits in different physical locations on the processor. This paper also discusses how these measurements can provide a better understanding of these types of errors and how they may improve efforts to validate the accuracy of quantum computations.}, number={2}, journal={QUANTUM INFORMATION PROCESSING}, author={Yeter-Aydeniz, Kubra and Parks, Zachary and Thekkiniyedath, Aadithya Nair and Gustafson, Erik and Kemper, Alexander F. and Pooser, Raphael C. and Meurice, Yannick and Dreher, Patrick}, year={2023}, month={Jan} }