Simple mitigation of global depolarizing errors in quantum simulations

TLDR

Error mitigation is essential to obtain the best possible results from current quantum devices. The authors propose a simple error‑mitigation technique that assumes deep‑circuit noise can be modeled as global depolarizing channels. They measure device errors, fit a depolarizing error model, and use it to infer error‑free results, demonstrating its effectiveness on entanglement measurements and real‑time dynamics in quantum spin chains. The method yields quantitative confinement signatures on IBM quantum computers, enabling extraction of meson masses, and shows broad applicability, device independence, and significant performance gains when global depolarization dominates.

Abstract

To get the best possible results from current quantum devices error mitigation is essential. In this work we present a simple but effective error mitigation technique based on the assumption that noise in a deep quantum circuit is well described by global depolarizing error channels. By measuring the errors directly on the device, we use an error model ansatz to infer error-free results from noisy data. We highlight the effectiveness of our mitigation via two examples of recent interest in quantum many-body physics: entanglement measurements and real-time dynamics of confinement in quantum spin chains. Our technique enables us to get quantitative results from the IBM quantum computers showing signatures of confinement, i.e., we are able to extract the meson masses of the confined excitations which were previously out of reach. Additionally, we show the applicability of this mitigation protocol in a wider setting with numerical simulations of more general tasks using a realistic error model. Our protocol is device-independent, simply implementable, and leads to large improvements in results if the global errors are well described by depolarization.