AI 中文总结
研究分布式量子计算中节点架构不对称问题，提出通过设计通信误差偏差避免蒸馏，减少辅助原子核需求，展示高纠错阈值，确定晶格手术的鲁棒性，放宽对通信量子比特相关要求。
AI 中文摘要
分布式量子计算通过光链路连接小型高质量节点，但该架构存在明显不对称性：节点内门操作和测量成本低且保真度高，而节点间通信依赖低相干通信量子比特和有故障的光子学。以往方法通过在每个节点放置多个高质量数据量子比特并用于贝尔对和GHZ态蒸馏来克服噪声链路。本文表明可完全避免蒸馏。关键在于设计通信误差偏差，使光子贝尔对频繁出现相位误差但很少有比特翻转误差。设计综合征提取电路，使相位噪声仅表现为不传播到数据量子比特的测量误差，通过简单重复测量来抑制。这大幅减少了辅助原子核的需求：弗洛凯码每个节点仅需一个数据量子比特，通用稳定器码仅需一个额外辅助比特。通过整个过程展示了高纠错阈值，并确定晶格手术在此设置下本质上具有鲁棒性，能在接近量子存储器的阈值下进行逻辑操作。结果，量子计算机的性能受高质量数据量子比特限制，而对通信量子比特的光子不可区分性和相干性要求大幅放宽。
英文摘要
Distributed quantum computing interconnects small, high-quality nodes through optical links, but this architecture carries a pronounced asymmetry: in-node gates and measurements are cheap and high-fidelity, whereas inter-node communication relies on a low-coherence communication qubit and faulty photonics. Previous approaches overcame the noisy link by placing several high-quality data qubits in each node and consuming them for Bell pair and GHZ state distillation. Here we show that distillation can be avoided altogether. The key observation is that we can engineer a communication error bias, where photonic Bell pairs suffer frequent phase errors but only rare bit-flip errors. We design the syndrome-extraction circuits so that this phase noise appears solely as a measurement error that does not propagate to the data qubits, and is therefore suppressed by simply repeating the measurement; letting the error-correcting code itself, rather than a dedicated distillation subroutine, to purify the link. This dramatically reduces the need for ancillary nuclei: Floquet codes require only a single data qubit per node, while general stabilizer codes require just one additional ancilla. We demonstrate high error-correction thresholds throughout this regime, and we identify lattice surgery as inherently robust for this setting, enabling logical operations at a threshold close to that of quantum memory. As a result, the performance of the quantum computer is limited by the high-quality data qubits, while the requirements on photon indistinguishability and coherence of the communication qubit are substantially relaxed.
