Shadow Distillation: Quantum Error Mitigation with Classical Shadows for Near-Term Quantum Processors

TL;DR

This paper introduces Shadow Distillation, a quantum error mitigation technique using classical shadows and randomized measurements, effective for near-term quantum processors without requiring multiple coherent copies.

Contribution

It presents a novel error mitigation method leveraging classical shadows that reduces resource overhead compared to full state tomography.

Findings

Overhead is favorable compared to full tomography.

Method improves stabilizer measurements in experiments.

Analyzes error sources in GHZ state preparation.

Abstract

Mitigating errors in quantum information processing devices is especially important in the absence of fault tolerance. An effective method in suppressing state-preparation errors is using multiple copies to distill the ideal component from a noisy quantum state. Here, we use classical shadows and randomized measurements to circumvent the need for coherent access to multiple copies at an exponential cost. We study the scaling of resources using numerical simulations and find that the overhead is still favorable compared to full state tomography. We optimize measurement resources under realistic experimental constraints and apply our method to an experiment preparing Greenberger-Horne-Zeilinger (GHZ) state with trapped ions. In addition to improving stabilizer measurements, the analysis of the improved results reveals the nature of errors affecting the experiment. Hence, our results provide a directly applicable method for mitigating errors in near-term quantum computers.