One of the most promising routes toward scalable quantum computing is a modular approach. We show that distinct surface code patches can be connected in a fault-tolerant manner even in the presence of substantial noise along their connecting interface. We quantify analytically and numerically the combined effect of errors across the interface and bulk. We show that the system can tolerate 14 times higher noise at the interface compared to the bulk, with only a small effect on the code’s threshold and subthreshold behavior, reaching threshold with ~1% bulk errors and ~10% interface errors. This implies that fault-tolerant scaling of error-corrected modular devices is within reach using existing technology.

模块化方法是实现可扩展量子计算最有希望的途径之一。我们证明，即使在连接接口上存在大量噪声的情况下，不同的表面代码补丁也可以以容错方式连接。我们以分析和数值方式量化了界面和体积误差的综合影响。我们表明，与本体相比，系统可以容忍接口处的噪声高出 14 倍，对代码的阈值和亚阈值行为影响很小，达到阈值时本体错误约为 1%，接口错误约为 10%。这意味着使用现有技术可以实现纠错模块化设备的容错扩展。