[LINK] Physics and obscure April Fool jokes

[Richard Chirgwin]

I think this is an April Foolery. The only thing is, I don't have enough 
quantum physics to be sure ...

http://arxiv.org/abs/1004.0255

>
>   Surface code quantum error correction incorporating accurate error
>   propagation
>
> Authors: Austin G. Fowler 
> <http://arxiv.org/find/quant-ph/1/au:+Fowler_A/0/1/0/all/0/1>, David 
> S. Wang <http://arxiv.org/find/quant-ph/1/au:+Wang_D/0/1/0/all/0/1>, 
> Lloyd C. L. Hollenberg 
> <http://arxiv.org/find/quant-ph/1/au:+Hollenberg_L/0/1/0/all/0/1>
> (Submitted on 1 Apr 2010)
>
>     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. 
>

I think the hint is in the headline, "incorporating accurate error 
propagation" ...

RC