基于微波猫总线的容错量子计算
Fault-tolerant quantum computing with a microwave Cat Bus
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中文总结 AI 辅助
本文提出基于微波猫总线的无需转运的容错中性原子量子计算架构，其利用猫总线实现全对全连通，可大幅缩短校验子提取周期并提升误差阈值，为高速容错中性原子量子计算提供新方案。
中文摘要 AI 辅助
容错中性原子量子计算机的可扩展性受光镊转运延迟的限制，这在量子算法编译中对量子比特开销和电路深度构成了严格的权衡。本文提出一种硬件高效、无需转运的架构，可实现全对全连通性：远程里德伯原子通过微波“猫总线”（一种自发稳定在玻色猫态的腔模）发生共振纠缠。猫总线原生支持高度并行的一对多$\text{CZ}^n$门执行，串扰呈指数级抑制。我们从基础相互作用和物理约束推导得到猫-原子误差信道。为实现容错操作，我们开发了硬件感知调度方案，利用原生猫-原子$\text{CZ}^n$门构建深度最小的纠错码校验子提取电路。我们用超图积（HGP）码对该架构进行基准测试，估计在$N=10^5$个数据量子比特时，与基于原子重排的架构相比，校验子提取周期时间减少180倍；在匹配的两量子比特去极化噪声下，对应的误差阈值从0.55%提升至0.72%；在硬件推导的误差模型下，我们得到阈值为0.80%，对应阈值协同度$C_{\text{th}}=7.8\times10^4$，与里德伯耦合微波腔系统的实验可及参数兼容。通过避免原子传输，猫总线为高速容错中性原子量子计算提供了一条途径。
英文摘要
The scalability of fault-tolerant neutral-atom quantum computers is constrained by the latency of shuttling with optical tweezers, imposing a stringent trade-off between qubit overhead and circuit depth in quantum algorithm compilation. Here we propose a hardware-efficient, shuttling-free architecture that achieves all-to-all connectivity. Remote Rydberg atoms are resonantly entangled through a microwave ``Cat Bus''---a cavity mode autonomously stabilized in a bosonic cat state. The Cat Bus natively supports the highly parallelized execution of one-to-many $\mathrm{CZ}^n$ gates with exponentially suppressed crosstalk. We derive the resulting cat--atom error channel from the underlying interactions and physical constraints. For fault-tolerant operation, we develop a hardware-aware scheduling scheme that exploits the native cat--atom $\mathrm{CZ}^{n}$ gate to construct a syndrome-extraction circuit with minimum depth. We benchmark the architecture using hypergraph-product (HGP) codes and estimate a 180-fold reduction in syndrome-extraction cycle time at $N=10^5$ data qubits compared with an atom-rearrangement-based architecture. Under matched two-qubit depolarizing noise, the corresponding error threshold increases from $0.55\%$ to $0.72\%$. Under the hardware-derived error model, we obtain a threshold of $0.80\%$, corresponding to a threshold cooperativity of $C_{\mathrm{th}}=7.8 \times 10^4$, compatible with experimentally accessible parameters for Rydberg-coupled microwave-cavity systems. By avoiding atom transport, the Cat Bus provides a route towards high-speed, fault-tolerant neutral-atom quantum computation.
