In this work, we study and improve two leading error mitigation techniques, namely Probabilistic Error Cancellation (PEC) and Zero-Noise Extrapolation (ZNE), for estimating the expectation value of local observables. For PEC, we introduce a new estimator that takes into account the light cone of the unitary circuit with respect to a target local observable. Given a fixed error tolerance, the sampling overhead for the new estimator can be several orders of magnitude smaller than the standard PEC estimators. For ZNE, we also use light-cone arguments to establish an error bound that closely captures the behavior of the bias that remains after extrapolation.
Cite
@article{arxiv.2303.06496,
title = {Locality and Error Mitigation of Quantum Circuits},
author = {Minh C. Tran and Kunal Sharma and Kristan Temme},
journal= {arXiv preprint arXiv:2303.06496},
year = {2023}
}