Three-qubit Parity Gate via Simultaneous Cross Resonance Drives

TL;DR

This paper demonstrates an efficient three-qubit parity gate using simultaneous cross-resonance drives, improving fidelity and error rates in quantum error correction on superconducting qubits.

Contribution

It introduces a novel calibration and implementation method for three-qubit parity gates with simultaneous drives, enhancing performance over traditional approaches.

Findings

Higher randomized benchmarking fidelities with simultaneous drives

Significant reduction in parity measurement error probability

Effective implementation on IBM Quantum superconducting qubits

Abstract

Native multi-qubit parity gates have various potential quantum computing applications, such as entanglement creation, logical state encoding and parity measurement in quantum error correction. Here, using simultaneous cross-resonance drives on two control qubits with a common target, we demonstrate an efficient implementation of a three-qubit parity gate. We have developed a calibration procedure based on the one for the echoed cross-resonance gate. We confirm that our use of simultaneous drives leads to higher interleaved randomized benchmarking fidelities than a naive implementation with two consecutive CNOT gates. We also demonstrate that our simultaneous parity gates can significantly improve the parity measurement error probability for the heavy-hexagon code on an IBM Quantum processor using seven superconducting qubits with all-microwave control.