Generating and detecting genuine multipartite entanglement (GME) of sizeable quantum states prepared on physical devices is an important benchmark for highlighting the progress of near-term quantum computers. A common approach to certify GME is to prepare a Greenberger-Horne-Zeilinger (GHZ) state and measure a GHZ fidelity of at least 0.5. We measure the fidelities using multiple quantum coherences of GHZ states on 11 to 27 qubits prepared on the IBM Quantum ibmq_montreal device. Combinations of quantum readout error mitigation (QREM) and parity verification error detection are applied to the states. A fidelity of 0.5460.017 was recorded for a 27-qubit GHZ state when QREM was used, demonstrating GME across the full device with a confidence level of 98.6%. We benchmarked the effect of parity verification on GHZ fidelity for two GHZ state preparation embeddings on the heavy-hexagon architecture. The results show that the effect of parity verification, while relatively modest, led to a detectable improvement of GHZ fidelity.

生成和检测在物理设备上准备的相当大的量子态的真正多方纠缠 (GME) 是突出近期量子计算机进展的重要基准。认证 GME 的常用方法是准备格林伯格-霍恩-蔡林格 (GHZ) 状态并测量至少 0.5 的 GHZ 保真度。我们使用在 IBM Quantum ibmq _ montreal上准备的 11 到 27 个量子位上的 GHZ 状态的多个量子相干性来测量保真度设备。量子读出错误缓解 (QREM) 和奇偶校验错误检测的组合应用于状态。当使用 QREM 时，27 量子比特 GHZ 状态的保真度为 0.5460.017，表明整个设备的 GME 具有 98.6% 的置信水平。我们对重六边形架构上的两个 GHZ 状态准备嵌入的奇偶校验对 GHZ 保真度的影响进行了基准测试。结果表明，奇偶校验的效果虽然相对温和，但导致 GHZ 保真度的显着提高。