Quantum Twist to Complementarity: A Duality Relation

Some recent works have introduced a quantum twist to the concept of complementarity, exemplified by a setup in which the which-way detector is in a superposition of being present and absent. It has been argued that such experiments allow measurement of particle-like and wave-like behavior at the same time. Here we derive an inequality which puts a bound on the visibility of interference and the amount of which-way information that one can obtain, in the context of such modified experiments. As the wave-aspect can only be revealed by an ensemble of detections, we argue that in such experiments, a single detection can contribute only to one subensemble, corresponding to either wave-aspect or particle aspect. This way, each detected particle behaves either as particle or as wave, never both, and Bohr's complementarity is fully respected.Comment: Final version, to appear as letter in Prog. Theor. Exp. Phy

Positive Surge Propagation in Sloping Channels

A simplified model for the upstream propagation of a positive surge in a sloping, rectangular channel is presented. The model is based on the assumptions of a flat water surface and negligible energy dissipation downstream of the surge, which is generated by the instantaneous closure of a downstream gate. Under these hypotheses, a set of equations that depends only on time accurately describes the surge wave propagation. When the Froude number of the incoming flow is relatively small, an approximate analytical solution is also proposed. The predictive ability of the model is validated by comparing the model results with the results of an experimental investigation and with the results of a numerical model that solves the full shallow water equations

Tools In Practice. Genealogy To Tackle Academic Inequalities

This paper introduces the method of genealogy to analyse the government of disability in Italian higher education contexts. Looking at how power and discourses construct disability within the academic setting, I problematize the truths that, throughout the last century, brought disabled subjects to be part of the mainstreamed education. Ethnographic work within a specific university milieu situated my research in the present of disabled students. That provides me with the access to tactics and power relations in specific and local settings, problematising the use of standardised criteria and classificatory systems. In depth-interviews with disabled students allow me to look for those technologies of power that work on the bodies and in the souls of disabled subjects, enabling me to delve into disabled students’ subjectivities. Seeing disability as a complex social function (Foucault, 1978; Peter and Fendler, 2003), the study shows how relations of power within precise historical, political and economic factors fashion the ways we are governed and we govern ourselves

A quantum delayed choice experiment

Quantum systems exhibit particle-like or wave-like behaviour depending on the experimental apparatus they are confronted by. This wave-particle duality is at the heart of quantum mechanics, and is fully captured in Wheeler's famous delayed choice gedanken experiment. In this variant of the double slit experiment, the observer chooses to test either the particle or wave nature of a photon after it has passed through the slits. Here we report on a quantum delayed choice experiment, based on a quantum controlled beam-splitter, in which both particle and wave behaviours can be investigated simultaneously. The genuinely quantum nature of the photon's behaviour is tested via a Bell inequality, which here replaces the delayed choice of the observer. We observe strong Bell inequality violations, thus showing that no model in which the photon knows in advance what type of experiment it will be confronted by, hence behaving either as a particle or as wave, can account for the experimental data

Riesgos potenciales de las micotoxinas en alimentos. Panorama regional de las toxinas deoxinivalenol y zearalenona

Riesgos potenciales de las micotoxinas en alimentos. Panorama regional de las toxinas deoxinivalenol y zearalenona.Fil: Pioli, Rosanna. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentin

Fosfatos naturais reativos: resultados obtidos no sul do Brasil.

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