Measuring error rates of mid-circuit measurements

TL;DR

This paper introduces a novel randomized benchmarking protocol to accurately measure error rates caused by mid-circuit measurements in multiqubit quantum processors, addressing a key gap in quantum error assessment.

Contribution

It presents the first protocol for comprehensive measurement-induced error rate assessment and demonstrates its effectiveness on trapped-ion and IBM Q quantum computers.

Findings

Detected and eliminated measurement-induced crosstalk in a 20-qubit system.

Quantified measurement-induced crosstalk error on a 27-qubit processor.

Showed dynamical decoupling reduces measurement-induced errors.

Abstract

High-fidelity mid-circuit measurements, which read out the state of specific qubits in a multiqubit processor without destroying them or disrupting their neighbors, are a critical component for useful quantum computing. They enable fault-tolerant quantum error correction, dynamic circuits, and other paths to solving classically intractable problems. But there are almost no methods to assess their performance comprehensively. We address this gap by introducing the first randomized benchmarking protocol that measures the rate at which mid-circuit measurements induce errors in many-qubit circuits. Using this protocol, we detect and eliminate previously undetected measurement-induced crosstalk in a 20-qubit trapped-ion quantum computer. Then, we use the same protocol to measure the rate of measurement-induced crosstalk error on a 27-qubit IBM Q processor, and quantify how much of that error is eliminated by dynamical decoupling.