Measurement Crosstalk Errors in Cloud-Based Quantum Computing

TL;DR

This paper investigates measurement crosstalk errors in cloud-based quantum computing systems, using quantum detector tomography to characterize and quantify noise, revealing entanglement as a source of crosstalk in multi-qubit measurements.

Contribution

It provides the first direct verification and detailed characterization of measurement crosstalk errors in cloud quantum computing platforms.

Findings

Measurement crosstalk errors exist in IBMQ and Rigetti systems.

Entanglement contributes to measurement crosstalk in three-qubit systems.

Quantitative analysis of measurement noise in multi-qubit readouts.

Abstract

Quantum technologies available currently contain noise in general, often dubbed noisy intermediate-scale quantum (NISQ) systems. We here present the verification of noise in measurement readout errors in cloud-based quantum computing services, IBMQ and Rigetti, by directly performing quantum detector tomography, and show that there exist measurement crosstalk errors. We provide the characterization and the quantification of noise in a quantum measurement of multiple qubits. We remark that entanglement is found as a source of crosstalk errors in a measurement of three qubits.