发表机构
Harvard University; QuEra Computing Inc.; University of Maryland, College Park; California Institute of Technology; Massachusetts Institute of Technology（哈佛大学; QuEra计算公司; 马里兰大学帕克分校; 加州理工学院; 麻省理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究结合三轮车码与四周期码，提出一种时空成本低10-40倍的单次魔法态工厂，可在高码率qLDPC架构下高效生成高保真CCZ态，为容错量子计算提供实用方案。
AI 中文摘要
量子低密度奇偶校验（qLDPC）码可大幅降低容错量子计算的量子比特开销，但基于这类码的任何实用架构还需一种高效的容错实现非克利福德门的机制。我们结合最新开发的三轮车码的横向非克利福德门与单次四维平衡乘积四周期码，为高码率qLDPC码引入了一种时空高效的魔法态工厂。核心要素是一种高效的“逃逸”机制，可将后选逻辑魔法态从三轮车码传送到更大距离的四周期码。在物理错误率为10⁻³的标准电路级噪声模型下，我们的工厂生成CCZ态的逻辑错误率低至10⁻⁹，时空成本比现有最优魔法态生成方法低10至40倍。生成的态直接编码为适合计算的高码率块。我们通过AI辅助搜索确定了四周期码，证明其可作为具备单次错误校正能力的优异存储器。最后，我们展示了整个工厂在可重构中性原子量子计算机上的高效原子传输的具体实现。这些结果共同提供了一种端到端的实用协议，用于在高码率qLDPC架构内生成和利用高保真魔法态，具有迄今最低的时空成本。
英文摘要
Quantum low-density parity-check (qLDPC) codes can substantially reduce the qubit overhead of fault-tolerant quantum computation, but any useful architecture based on such codes also requires an efficient mechanism to implement non-Clifford gates in a fault-tolerant manner. We introduce a space-time-efficient magic state factory for high-rate qLDPC codes by combining the transversal non-Clifford gates of recently developed tricycle codes with single-shot four-dimensional balanced product quadcycle codes. The key ingredient is an efficient "escape" mechanism that teleports postselected logical magic states from tricycle codes to larger distance quadcycle codes. Under a standard circuit-level noise model at physical error rate $10^{-3}$, our factories produce $\mathrm{CCZ}$ states at logical error rates as low as $10^{-9}$ with 10-40 times lower space-time cost than state-of-the-art magic state generation methods. The resulting states are directly encoded in high-rate blocks suitable for computation. We identify the quadcycle codes by an AI-assisted search and show that they can serve as excellent memories capable of single-shot error correction. Finally, we present a concrete implementation of the entire factory with highly efficient atom transport on reconfigurable neutral-atom quantum computers. Together, these results provide an end-to-end, practical protocol for producing and utilizing high-fidelity magic states within a high-rate qLDPC architecture, with the lowest space-time cost to date.
Comments17 main text pages, 6 main figures, Supplementary Information appended. Atom movement animation included in ancillary files
