State-preparation and measurement error mitigation with non-computational states

TL;DR

This paper introduces a method using non-computational states to better characterize and mitigate state-preparation, gate, and measurement errors in superconducting qubits, enhancing quantum error correction.

Contribution

It demonstrates how leveraging non-computational states can fully constrain noise models, enabling more accurate error mitigation in quantum circuits.

Findings

Successfully constrains noise models using non-computational states.

Improves mitigation of state-preparation, gate, and measurement errors.

Applicable to dynamic circuits with mid-circuit measurements.

Abstract

Error mitigation has enabled quantum computing applications with over one hundred qubits and deep circuits. The most general error mitigation methods rely on a faithful characterization of the noise channels of the hardware. However, fundamental limitations lead to unlearnable degrees of freedom of the underlying noise models when considering qubits. Here, we show how to leverage non-computational states as an additional resource to learn state-preparation errors in superconducting qubits. This allows one to fully constrain the noise models. We can thus independently and accurately mitigate state-preparation errors, gate errors and measurement errors. Our proposed method is also applicable to dynamic circuits with mid-circuit measurements. This work opens the door to improved error mitigation for measurements, both at the end of the circuit and mid-circuit.