Marginalised youth, violence and policing: a qualitative study in Recife, Brazil

Few studies have examined the relations between urban marginalised youth and the public security system in the northeast of Brazil. This article addresses this gap in the literature through an examination of youth perceptions of a security programme aimed at reducing violence. It also analyses the effects of this security program by interrogating the hegemonic discourses of state-actors in the region, namely, agents of the criminal justice system. The analysis draws on ethnographic data collected between 2012 and 2016 in Recife, the capital city of the state of Pernambuco in the northeast of Brazil. This approach permits an examination of the nature of new security interventions, and a comparison between two distinct narratives about this new securitisation agenda. One overarching narrative focuses on young people’s vulnerabilities, the other on claims of successful securitisation. An analysis of these narratives widens understandings of the effects and risks of security interventions, contributing to a debate about their impact on young people’s lives and society at large

Classical causal models for Bell and Kochen-Specker inequality violations require fine-tuning

Nonlocality and contextuality are at the root of conceptual puzzles in quantum mechanics, and are key resources for quantum advantage in information-processing tasks. Bell nonlocality is best understood as the incompatibility between quantum correlations and the classical theory of causality, applied to relativistic causal structure. Contextuality, on the other hand, is on a more controversial foundation. In this work, I provide a common conceptual ground between nonlocality and contextuality as violations of classical causality. First, I show that Bell inequalities can be derived solely from the assumptions of no-signalling and no-fine-tuning of the causal model. This removes two extra assumptions from a recent result from Wood and Spekkens, and remarkably, does not require any assumption related to independence of measurement settings -- unlike all other derivations of Bell inequalities. I then introduce a formalism to represent contextuality scenarios within causal models and show that all classical causal models for violations of a Kochen-Specker inequality require fine-tuning. Thus the quantum violation of classical causality goes beyond the case of space-like separated systems, and manifests already in scenarios involving single systems.Comment: 9 pages, 14 figures. Modified title, discussion and presentatio