Pattern-based quantum functional testing

TL;DR

This paper introduces a pattern-based testing method for quantum devices that efficiently detects errors, characterizes qubit behavior, and identifies crosstalk and non-Markovian effects, aiding rapid device assessment.

Contribution

It adapts classical memory testing algorithms to quantum systems, providing a novel approach for quick and effective quantum device characterization.

Findings

Successfully extracts pattern dependencies of qubit properties

Identifies interactions and crosstalk effects between qubits

Detects signatures of non-Markovian dynamics

Abstract

With the growing number of qubits of quantum information processing devices, the task of fully characterizing these processors becomes increasingly unfeasible. From a practical perspective, one wants to find possible errors in the functioning of the device as quickly as possible, or otherwise establish its correct functioning with high confidence. In response to these challenges, we propose a pattern-based approach inspired by classical memory testing algorithms to evaluate the functionality of a quantum memory, based on plausible failure mechanisms. We demonstrate the method's capability to extract pattern dependencies of important qubit characteristics, such as $T_1$ and $T_2$ times, and to identify and analyze interactions between adjacent qubits. Additionally, our approach enables the detection of different types of crosstalk effects and of signatures indicating non-Markovian dynamics in individual qubits.