On a purported local extension of the quantum formalism

Since the early days of quantum mechanics, a number of physicists have doubted whether quantum mechanics was a complete theory and wondered whether it was possible to extend the quantum formalism by adjoining hidden variables.1 In 1952, Bohm answered this question in the affirmative2 and in doing so refuted von Neumann’s influential yet flawed proof that no such extension was possible.3 However, Bohm’s hidden variable theory has not won wide support partly because the theory is nonlocal: there is instantaneous action at a distance. Since there is an obvious problem reconciling such nonlocal theories with Relativity, hidden variable theories would look much more promising if they also satisfied locality. Accordingly, the question as to whether or not local hidden variable theories are possible assumes great significance. In 1964 Bell appeared to prove that this question had a negative answer:4 He showed that any local hidden variables theory is incompatible with certain quantum mechanical predictions. Since these predictions have been borne out by the experiments of Aspect and others5 the prospects for hidden variable theories have looked grim. Angelidis disagrees.6 He claims to have done to Bell what Bohm did to von Neummann: He has found a theory which is local and which generates a family of probability functions converging uniformly to the probability function generated by quantum mechanics. If this were true, then Angelidis’ theory would be a counterexample to Bell’s theorem and a promising path would once again be open to hidden variable theorists. Unfortunately, Angelidis’ theory fails to live up to his claims: As formulated, the theory does not make the same predictions as quantum mechanics, and while there is a natural extension of his theory which does make the same predictions, the extension is not local. Bell’s Theorem stands

Modern ‘live’ football: moving from the panoptican gaze to the performative, virtual and carnivalesque

Drawing on Redhead's discussion of Baudrillard as a theorist of hyperreality, the paper considers the different ways in which the mediatized ‘live’ football spectacle is often modelled on the ‘live’ however eventually usurps the ‘live’ forms position in the cultural economy, thus beginning to replicate the mediatized ‘live’. The blurring of the ‘live’ and ‘real’ through an accelerated mediatization of football allows the formation of an imagined community mobilized by the working class whilst mediated through the sanitization, selling of ‘events’ and the middle classing of football, through the re-encoding of sporting spaces and strategic decision-making about broadcasting. A culture of pub supporting then allows potential for working-class supporters to remove themselves from the panoptican gazing systems of late modern hyperreal football stadia and into carnivalesque performative spaces, which in many cases are hyperreal and simulated themselves

State-dependent rotations of spins by weak measurements

IIt is shown that a weak measurement of a quantum system produces a new state of the quantum system which depends on the prior state, as well as the (uncontrollable) measured position of the pointer variable of the weak measurement apparatus. The result imposes a constraint on hidden-variable theories which assign a different state to a quantum system than standard quantum mechanics. The constraint means that a crypto-nonlocal hidden-variable theory can be ruled out in a more direct way than previously.Comment: 10 pages, 2 figures. Substantially revised to concentrate on weak measurement transformation of states and application to crypto-nonlocal hidden-variable theor

Comment on ``All quantum observables in a hidden-variable model must commute simultaneously"

Malley discussed {[Phys. Rev. A {\bf 69}, 022118 (2004)]} that all quantum observables in a hidden-variable model for quantum events must commute simultaneously. In this comment, we discuss that Malley's theorem is indeed valid for the hidden-variable theoretical assumptions, which were introduced by Kochen and Specker. However, we give an example that the local hidden-variable (LHV) model for quantum events preserves noncommutativity of quantum observables. It turns out that Malley's theorem is not related with the LHV model for quantum events, in general.Comment: 3 page

Multipartite positive-partial-transpose inequalities exponentially stronger than local reality inequalities

We show that positivity of {\it every} partial transpose of $N$-partite quantum states implies new inequalities on Bell correlations which are stronger than standard Bell inequalities by a factor of $2^{(N-1)/2}$. A violation of the inequality implies the system is in a bipartite distillable entangled state. It turns out that a family of $N$-qubit bound entangled states proposed by D\"ur {[Phys. Rev. Lett. {\bf 87}, 230402 (2001)]} violates the inequality for $N\geq 4$.Comment: 4 pages, To appear in Phys. Rev.

Bipartite Bell inequalities for hyperentangled states

We show that bipartite Bell inequalities based on the Einstein-Podolsky-Rosen criterion for elements of reality and derived from the properties of some hyperentangled states allow feasible experimental verifications of the fact that quantum nonlocality grows exponentially with the size of the subsystems, and Bell loophole-free tests with currently available photodetection efficiencies.Comment: REVTeX4, 5 page

Classification of local realistic theories

Recently, it has shown that an explicit local realistic model for the values of a correlation function, given in a two-setting Bell experiment (two-setting model), works only for the specific set of settings in the given experiment, but cannot construct a local realistic model for the values of a correlation function, given in a {\it continuous-infinite} settings Bell experiment (infinite-setting model), even though there exist two-setting models for all directions in space. Hence, two-setting model does not have the property which infinite-setting model has. Here, we show that an explicit two-setting model cannot construct a local realistic model for the values of a correlation function, given in a {\it only discrete-three} settings Bell experiment (three-setting model), even though there exist two-setting models for the three measurement directions chosen in the given three-setting experiment. Hence, two-setting model does not have the property which three-setting model has.Comment: To appear in Journal of Physics A: Mathematical and Theoretica

Cholecystobronchocolic Fistula: A Late Complication of Biliary Sepsis

A case of a 48 year old woman presenting with bilioptysis due to a cholecystobronchocolic fistula is reported. Bilioptysis is a rare complication of biliary fistulae, with a high mortality due to chemical pneumonitis. Bronchospasm and rapid respiratory failure may ensue if aggressive management is not adopted. The site of fistulation is established by cholangiography, preferably by the percutaneous transhepatic route. Continued biliary drainage can lead to closure of these fistulae, or allow sufficient improvement in clinical condition to allow definitive surgery to be performed electively