Does the quantum state represent reality or our knowledge of reality? In making this distinction precise, we are led to a novel classification of hidden variable models of quantum theory. We show that representatives of each class can be found among existing constructions for two-dimensional Hilbert spaces. Our approach also provides a fruitful new perspective on arguments for the nonlocality and incompleteness of quantum theory. Specifically, we show that for models wherein the quantum state has the status of something real, the failure of locality can be established through an argument considerably more straightforward than Bell's theorem. The historical significance of this result becomes evident when one recognizes that the same reasoning is present in Einstein's preferred argument for incompleteness, which dates back to 1935. This fact suggests that Einstein was seeking not just any completion of quantum theory, but one wherein quantum states are solely representative of our knowledge. Our hypothesis is supported by an analysis of Einstein's attempts to clarify his views on quantum theory and the circumstance of his otherwise puzzling abandonment of an even simpler argument for incompleteness from 1927.

We show that correlations inconsistent with any locally causal description can be a generic feature of measurements on entangled quantum states. Specifically, spatially separated parties who perform local measurements on a maximally entangled state using randomly chosen measurement bases can, with significant probability, generate nonclassical correlations that violate a Bell inequality. For n parties using a Greenberger-Horne-Zeilinger state, this probability of violation rapidly tends to unity as the number of parties increases. We also show that, even with both a randomly chosen two-qubit pure state and randomly chosen measurement bases, a violation can be found about 10% of the time. Among other applications, our work provides a feasible alternative for the demonstration of Bell inequality violation without a shared reference frame.

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While migration health studies traditionally focused on socioeconomic determinants of health, an emerging body of literature is exploring migration status as a proximate cause of health outcomes. Study 1 is a path analysis of the predictors of mental health amongst 582 documented migrant workers in Singapore, and shows that threat of deportation is one of the most important proximate social determinants of predicted mental illness, and a mediator of the impact of workplace conflict on mental health. Study 2 is a qualitative study of the narratives of 149 migrant workers who were in workplace conflict with their employers, and demonstrates that workers believed threats were used as a negotiating strategy during workplace conflicts. Findings suggest that migration status places workers who come into workplace conflict with their employers at heightened risk of mental illness because migration status can be used as a tool by employers in workplace negotiations.