Optimized scheme for operating the surface code in the presence of dead components

The physical implementation of a large-scale error corrected quantum processor will necessarily need to mitigate the presence of defective (thereby lost or “dead”) physical components in its operation, for example, identified during bring-up of the device or detected in the middle of a computation. In the context of solid state qubits, the QEC protocol operating in the presence of dead components should ideally (i) use the same native operation set as that without dead components, (ii) maximize salvaging of functional components, and (iii) use a consistent global operating schedule which optimizes logical qubit performance. We present a scheme for handling static dead components in the surface code, which satisfies all three of these criteria and can be universally applied to any physical surface code realization [1]. Furthermore, we conduct extensive numerical simulations of logical performance under circuit-level noise for the pairwise-measurement-based surface code protocol of Ref. [1] in the presence of dead components, and discuss various salient aspects of the problem, including dependence of code performance and structure of the resulting decoding problem on the choice of operating schedule.

[1] Grans-Samuelsson et al., Quantum 8, 1429 (2024).