Surface code quantum error correction incorporating accurate error propagation

TL;DR

This paper improves surface code quantum error correction by accurately modeling error propagation during two-qubit interactions, resulting in a quadratic reduction in logical error rates.

Contribution

It introduces a method that incorporates error propagation effects into the surface code decoding process, enhancing error correction performance.

Findings

Quadratic improvement in logical error rate when accounting for error propagation.

Enhanced accuracy in error detection and correction.

Potential for more reliable quantum computing implementations.

Abstract

The surface code is a powerful quantum error correcting code that can be defined on a 2-D square lattice of qubits with only nearest neighbor interactions. Syndrome and data qubits form a checkerboard pattern. Information about errors is obtained by repeatedly measuring each syndrome qubit after appropriate interaction with its four nearest neighbor data qubits. Changes in the measurement value indicate the presence of chains of errors in space and time. The standard method of determining operations likely to return the code to its error-free state is to use the minimum weight matching algorithm to connect pairs of measurement changes with chains of corrections such that the minimum total number of corrections is used. Prior work has not taken into account the propagation of errors in space and time by the two-qubit interactions. We show that taking this into account leads to a quadratic improvement of the logical error rate.