Another arxiv preprint by the same authors has more detail, and seems to be the essentially the same article but fleshed out more: <a href="http:&#x2F;&#x2F;arxiv.org&#x2F;abs&#x2F;1111.4443" rel="nofollow">http:&#x2F;&#x2F;arxiv.org&#x2F;abs&#x2F;1111.4443</a>