# An upper bound on quantum fault tolerant thresholds

@article{Fern2008AnUB, title={An upper bound on quantum fault tolerant thresholds}, author={Jesse Fern}, journal={arXiv: Quantum Physics}, year={2008} }

In this paper we calculate upper bounds on fault tolerance, without restrictions on the overhead involved. Optimally adaptive recovery operators are used, and the Shannon entropy is used to estimate the thresholds. By allowing for unrealistically high levels of overhead, we find a quantum fault tolerant threshold of 6.88% for the depolarizing noise used by Knill, which compares well to "above 3%" evidenced by Knill. We conjecture that the optimal threshold is 6.90%, based upon the hashing rate…

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