Subsystem fault tolerance with the Bacon-Shor code

Aliferis, Panos; Cross, Andrew W.

Subsystem fault tolerance with the Bacon-Shor code

Authors

Description

We discuss how the presence of gauge sub-systems in the Bacon-Shor code [D. Bacon, Phys. Rev. A 73, 012340 (2006)] leads to remarkably simple and efficient methods for fault-tolerant error correction (FTEC). Most notably, FTEC does not require entangled ancillary states and it can be implemented with nearest-neighbor two-qubit measurements. By using these methods, we prove a lower bound on the quantum accuracy threshold, 1.94 \times 10^{-4} for adversarial stochastic noise, that improves previous lower bounds by nearly an order of magnitude.
4 pages, 2 figures. v3: small revisions, appendix moved to chapter 5 in quant-ph/0703230