Optimized noise-resilient surface code teleportation interfaces

Abstract

Connecting two surface-code patches may require significantly higher noise at the interface. We show, via circuit-level simulations under a depolarizing noise model with idle errors, that surface codes remain fault tolerant despite substantially elevated interface error rates. Specifically, we compare three strategies -- direct noisy links, gate teleportation, and a CAT-state gadget -- for both rotated and unrotated surface codes, and demonstrate that careful design can mitigate hook errors in each case so that the full code distance is preserved for both $X$ and $Z$. Although these methods differ in space and time overhead and performance, each offers a viable route to modular surface-code architectures. Our results, obtained with Stim and PyMatching, confirm that high-noise interfaces can be integrated fault-tolerantly without compromising the code's essential properties, indicating that fault-tolerant scaling of error-corrected modular devices is within reach with current technology.