Kitaev's Zd-code threshold estimates

We study the quantum error correction threshold of Kitaev's toric code over the group Z(d) subject to a generalized bit-flip noise. This problem requires special decoding techniques, and for this purpose we generalize the renormalization-group method we introduced previously [G. Duclos-Cianci and D. Poulin, Phys. Rev. Lett. 104, 050504 (2010) and IEEE Information Theory Workshop, Dublin (2010), p. 1] for Z(2) topological codes.