  Quantum information can be protected from decoherence and other errors, but
only if these errors are sufficiently rare. For quantum computation to become a
scalable technology, practical schemes for quantum error correction that can
tolerate realistically high error rates will be necessary. In some physical
systems, errors may exhibit a characteristic structure that can be carefully
exploited to improve the efficacy of error correction. Here, we describe a
scheme for topological quantum error correction to protect quantum information
from a dephasing-biased error model, where we combine a repetition code with a
topological cluster state. We find that the scheme tolerates error rates of up
to 1.37%-1.83% per gate, requiring only short-range interactions in a
two-dimensional array.
