Logical pre- and post-selection paradoxes are proofs of contextuality

If a quantum system is prepared and later post-selected in certain states, "paradoxical" predictions for intermediate measurements can be obtained. This is the case both when the intermediate measurement is strong, i.e. a projective measurement with Luders-von Neumann update rule, or with weak measurements where they show up in anomalous weak values. Leifer and Spekkens [quant-ph/0412178] identified a striking class of such paradoxes, known as logical pre- and post-selection paradoxes, and showed that they are indirectly connected with contextuality. By analysing the measurement-disturbance required in models of these phenomena, we find that the strong measurement version of logical pre- and post-selection paradoxes actually constitute a direct manifestation of quantum contextuality. The proof hinges on under-appreciated features of the paradoxes. In particular, we show by example that it is not possible to prove contextuality without Luders-von Neumann updates for the intermediate measurements, nonorthogonal pre- and post-selection, and 0/1 probabilities for the intermediate measurements. Since one of us has recently shown that anomalous weak values are also a direct manifestation of contextuality [arXiv:1409.1535], we now know that this is true for both realizations of logical pre- and post-selection paradoxes.Comment: In Proceedings QPL 2015, arXiv:1511.0118

“The Necessary War: Canadians Fighting the Second World War 1939–1943, Volume One (Book Review)” by Tim Cook & “Fight to the Finish: Canadians in the Second World War 1944–1945, Volume Two (Book Review)” by Tim Cook

Review of The Necessary War: Canadians Fighting the Second World War 1939–1943, Volume One & Fight to the Finish: Canadians in the Second World War 1944–1945, Volume Two by Tim Cook

No Coincidence?

This paper critically examines coincidence arguments and evolutionary debunking arguments against non-naturalist realism in metaethics. It advances a version of these arguments that goes roughly like this: Given a non-naturalist, realist metaethic, it would be cosmically coincidental if our first order normative beliefs were true. This coincidence undermines any prima facie justification enjoyed by those beliefs

The Hunt for Privacy Harms After \u3ci\u3eSpokeo\u3c/i\u3e

In recent years, due both to hacks that have leaked the personal information of hundreds of millions of people and to concerns about government surveillance, Americans have become more aware of the harms that can accompany the widespread collection of personal data. However, the law has not yet fully developed to recognize the concrete privacy harms that can result from what otherwise seems like ordinary economic activity involving the widespread aggregation and compilation of data. This Note examines cases in which lower federal courts have applied the Supreme Court’s directions for testing the concreteness of alleged intangible privacy injuries, and in particular how that inquiry has affected plaintiffs’ suits under statutes that implicate privacy concerns. This Note proposes that, in probing the concreteness of these alleged privacy harms, the courts, through the doctrine of standing, are engaging in work that could serve to revitalize the judiciary’s long-dormant analysis of the nature of privacy harms. It suggests that courts should look beyond the four traditional privacy torts to find standing for plaintiffs who bring claims against entities that collect and misuse personal information. This Note urges courts to make use of a nexus approach to identify overlapping privacy concerns sufficient for standing, which would allow the federal judiciary to more adequately address emerging privacy harms