We measure and quantify non-Markovian effects in IBM's Quantum Experience. Specifically, we analyze the temporal correlations in a sequence of gates by characterizing the performance of a gate conditioned on the gate that preceded it. With this method, we estimate (i) the size of fluctuations in the performance of a gate, i.e., errors due to non-Markovianity; (ii) the length of the memory; and (iii) the total size of the memory. Our results strongly indicate the presence of non-trivial non-Markovian effects in almost all gates in the universal set. However, based on our findings, we discuss the potential for cleaner computation by adequately accounting the non-Markovian nature of the machine.
@article{arxiv.1902.07980,
title = {Non-Markovian memory in IBMQX4},
author = {Joshua Morris and Felix A. Pollock and Kavan Modi},
journal= {arXiv preprint arXiv:1902.07980},
year = {2023}
}