Detection of temporal fluctuation in superconducting qubits for quantum error mitigation

TL;DR

This paper investigates the instability in superconducting qubits, identifying step-like error rate changes, and proposes a quantum error mitigation method based on post-selection, supported by numerical analysis.

Contribution

It introduces a method to detect and mitigate temporal fluctuations in qubit errors using post-selection, enhancing quantum error correction strategies.

Findings

Qubits show step-like error rate changes lasting minutes.

Correlation between errors and output variance supports mitigation approach.

Numerical analysis validates the effectiveness of the proposed method.

Abstract

We have investigated instability of a superconducting quantum computer by continuously monitoring the qubit output. We found that qubits exhibit a step-like change in the error rates. This change is repeatedly observed, and each step persists for several minutes. By analyzing the correlation between the increased errors and anomalous variance of the output, we demonstrate quantum error mitigation based on post-selection. Numerical analysis on the proposed method was also conducted.