Dynamical decoupling (DD) is one of the simplest error suppression methods, aiming to enhance the coherence of qubits in open quantum systems. Moreover, DD has demonstrated effectiveness in reducing coherent crosstalk, one major error source in near-term quantum hardware, which manifests from two types of interactions. Static crosstalk exists in various hardware platforms, including superconductor and semiconductor qubits, by virtue of always-on qubit-qubit coupling. Additionally, driven crosstalk may occur as an unwanted drive term due to leakage from driven gates on other qubits. Here we explore a novel staggered DD protocol tailored for multi-qubit systems that suppresses the decoherence error and both types of coherent crosstalk. We develop two experimental setups—an ‘idle–idle’ experiment in which two pairs of qubits undergo free evolution simultaneously and a ‘driven-idle’ experiment in which one pair is continuously driven during the free evolution of the other pair. These experiments are performed on an IBM Quantum superconducting processor and demonstrate the significant impact of the staggered DD protocol in suppressing both types of coherent crosstalk. When compared to the standard DD sequences from state-of-the-art methodologies with the application of X2 sequences, our staggered DD protocol enhances circuit fidelity by 19.7% and 8.5%, respectively, in addressing these two crosstalk types.

中文翻译：

---

用于增强串扰抑制的多量子位动态解耦


动态解耦（DD）是最简单的错误抑制方法之一，旨在增强开放量子系统中量子位的相干性。此外，DD 已证明可以有效减少相干串扰，相干串扰是近期量子硬件中的一个主要误差源，表现为两种类型的相互作用。由于始终在线的量子位-量子位耦合，静态串扰存在于各种硬件平台中，包括超导体和半导体量子位。此外，由于其他量子位上的驱动门的泄漏，驱动串扰可能作为不需要的驱动项出现。在这里，我们探索了一种专为多量子位系统量身定制的新型交错 DD 协议，该协议可抑制退相干误差和两种类型的相干串扰。我们开发了两种实验装置：“空闲-空闲”实验，其中两对量子位同时进行自由演化；以及“驱动-空闲”实验，其中一对量子位在另一对量子位自由演化过程中被持续驱动。这些实验在 IBM Quantum 超导处理器上进行，证明了交错 DD 协议在抑制两种类型的相干串扰方面的显着影响。与应用 X2 序列的最先进方法的标准 DD 序列相比，我们的交错 DD 协议在解决这两种串扰类型方面分别将电路保真度提高了 19.7% 和 8.5%。