Quantum codes for asymmetric channels: ZZZY surface codes

TL;DR

This paper introduces ZZZY surface codes, a new family of quantum error-correcting codes optimized for asymmetric channels, which improve performance over traditional surface codes without added decoding complexity.

Contribution

The paper presents the design of ZZZY surface codes, a novel modification of surface codes tailored for asymmetric channels, compatible with existing MWPM decoding algorithms.

Findings

ZZZY codes outperform surface codes on asymmetric channels

Decoding uses standard MWPM with pre-processing, no extra complexity

Maintain correction capability on depolarizing channels

Abstract

We introduce surface ZZZY codes, a novel family of quantum error-correcting codes designed for asymmetric channels. Derived from standard surface codes through tailored modification of generators, ZZZY codes can be decoded by the minimum weight perfect matching (MWPM) algorithm with a suitable pre-processing phase. The resulting decoder exploits the information provided by the modified generators without introducing additional complexity. ZZZY codes demonstrate a significant performance advantage over surface codes when increasing the channel asymmetry, while maintaining the same correction capability over depolarizing channel.