近日，美国普林斯顿大学的Jeff D.Thompson及其研究小组取得一项新进展。经过不懈努力，他们实现原子量子比特中的高保真门和中间电路擦除转换。相关研究成果已于2023年10月11日在国际权威术期刊《自然》上发表。

该研究团队展示了一种全新的中性原子量子比特，利用¹⁷¹Yb中的长寿命亚稳态原子核自旋。这种设计使得单量子比特门和双量子比特门的保真度分别达到了0.9990(1)和0.980(1)，同时较长的相干时间和对里德伯态的快速激发也为实现高保真度提供了有力保障。更为重要的是，大部分门误差会导致量子比特子空间向基态的衰减，通过对这些误差执行快速的中间电路检测，研究人员成功地将它们转换为擦除误差。在检测过程中，计算空间中剩余量子比特的诱导误差概率被控制在小于10^-5的水平。这项工作为亚稳态¹⁷¹Yb作为实现容错量子计算的一个有前途的平台奠定了坚实基础。

据悉，发展可扩展、高保真的量子比特是量子信息科学领域的一个关键挑战。近年来，中性原子量子比特迅速发展，已经证实了可编程处理器和缩放到数百个原子的量子模拟器的可行性。探索新的原子种类，如碱土原子，或结合多种原子种类，为提高相干性、控制力和可扩展性提供了新的途径。例如，为了实现最终应用于量子纠错的目标，利用具有结构化误差模型的量子比特是有利的，如偏置泡利误差或将误差转换为可检测的擦除形式。

附：英文原文

Title: High-fidelity gates and mid-circuit erasure conversion in an atomic qubit

Author: Ma, Shuo, Liu, Genyue, Peng, Pai, Zhang, Bichen, Jandura, Sven, Claes, Jahan, Burgers, Alex P., Pupillo, Guido, Puri, Shruti, Thompson, Jeff D.

Issue&Volume: 2023-10-11

Abstract: The development of scalable, high-fidelity qubits is a key challenge in quantum information science. Neutral atom qubits have progressed rapidly in recent years, demonstrating programmable processors and quantum simulators with scaling to hundreds of atoms. Exploring new atomic species, such as alkaline earth atoms, or combining multiple species can provide new paths to improving coherence, control and scalability. For example, for eventual application in quantum error correction, it is advantageous to realize qubits with structured error models, such as biased Pauli errors or conversion of errors into detectable erasures. Here we demonstrate a new neutral atom qubit using the nuclear spin of a long-lived metastable state in ¹⁷¹Yb. The long coherence time and fast excitation to the Rydberg state allow one- and two-qubit gates with fidelities of 0.9990(1) and 0.980(1), respectively. Importantly, a large fraction of all gate errors result in decays out of the qubit subspace to the ground state. By performing fast, mid-circuit detection of these errors, we convert them into erasure errors; during detection, the induced error probability on qubits remaining in the computational space is less than 10^-5. This work establishes metastable ¹⁷¹Yb as a promising platform for realizing fault-tolerant quantum computing.

DOI: 10.1038/s41586-023-06438-1

Source: https://www.nature.com/articles/s41586-023-06438-1