论文标题
基于扭曲的晶格手术的电路级方案和分析
A circuit-level protocol and analysis for twist-based lattice surgery
论文作者
论文摘要
晶格手术是一种基于测量的技术,用于在二维中执行易耐断层量子计算。当使用表面代码时,最一般的晶格手术操作需要晶格不规则性,称为扭曲缺陷。但是,实施基于扭曲的晶格手术可能需要额外的资源,例如额外的设备连接,并可能降低表面代码的阈值和整体性能。在这里,我们提供了明确的基于扭曲的晶格手术协议及其必要的连接布局。我们还提供了新的稳定器测量电路,以测量与所选门调度兼容的扭曲缺陷。我们使用偏置的去极化噪声模型进行基于扭曲的晶格手术期间的第一个电路级误差校正模拟。我们的结果表明,与晶格手术方案相比,及时的逻辑失败的阈值略有下降,而散装中没有扭曲缺陷。但是,低于阈值(即,在$ 5 \ times 10^{ - 3} $的情况下,性能降解是温和的,实际上比建议的替代无扭曲的无扭曲方案更可取。最后,我们提供了一个有效的方案,用于测量$ y $ ocerators沿着表面代码的边界,绕过以前计划中所需的某些步骤。
Lattice surgery is a measurement-based technique for performing fault-tolerant quantum computation in two dimensions. When using the surface code, the most general lattice surgery operations require lattice irregularities called twist defects. However, implementing twist-based lattice surgery may require additional resources, such as extra device connectivity, and could lower the threshold and overall performance for the surface code. Here we provide an explicit twist-based lattice surgery protocol and its requisite connectivity layout. We also provide new stabilizer measurement circuits for measuring twist defects which are compatible with our chosen gate scheduling. We undertake the first circuit-level error correction simulations during twist-based lattice surgery using a biased depolarizing noise model. Our results indicate a slight decrease in the threshold for timelike logical failures compared to lattice surgery protocols with no twist defects in the bulk. However, comfortably below threshold (i.e. with CNOT infidelities below $5 \times 10^{-3}$), the performance degradation is mild and in fact preferable over proposed alternative twist-free schemes. Lastly, we provide an efficient scheme for measuring $Y$ operators along boundaries of surface codes which bypasses certain steps that were required in previous schemes.