Bound non-locality and activation

We investigate non-locality distillation using measures of non-locality based on the Elitzur-Popescu-Rohrlich decomposition. For a certain number of copies of a given non-local correlation, we define two quantities of interest: (i) the non-local cost, and (ii) the distillable non-locality. We find that there exist correlations whose distillable non-locality is strictly smaller than their non-local cost. Thus non-locality displays a form of irreversibility which we term bound non-locality. Finally we show that non-local distillability can be activated.Comment: 4 pages, 1 figur

Bell inequalities from multilinear contractions

We provide a framework for Bell inequalities which is based on multilinear contractions. The derivation of the inequalities allows for an intuitive geometric depiction and their violation within quantum mechanics can be seen as a direct consequence of non-vanishing commutators. The approach is motivated by generalizing recent work on non-linear inequalities which was based on the moduli of complex numbers, quaternions and octonions. We extend results on Peres conjecture about the validity of Bell inequalities for quantum states with positive partial transposes. Moreover, we show the possibility of obtaining unbounded quantum violations albeit we also prove that quantum mechanics can only violate the derived inequalities if three or more parties are involved.Comment: Published versio

Experimental Observation of Environment-induced Sudden Death of Entanglement

We demonstrate the difference between local, single-particle dynamics and global dynamics of entangled quantum systems coupled to independent environments. Using an all-optical experimental setup, we show that, while the environment-induced decay of each system is asymptotic, quantum entanglement may suddenly disappear. This "sudden death" constitutes yet another distinct and counter-intuitive trait of entanglement.Comment: 4 pages, 4 figure

Production of optical phase space vortices with non-locally distributed mode converters

Optical vortices have been observed in a wide variety of optical systems. They can be observed directly in the wavefront of optical beams, or in the correlations between pairs of entangled photons. We present a novel optical vortex which appears in a non-local plane of the two-photon phase space, composed of a single degree of freedom of each photon of an entangled pair. The preparation of this vortex can be viewed as a "non-local" or distributed mode converter. We show how these novel optical vortices of arbitrary order can be prepared in the spatial degrees of freedom of entangled photons.Comment: To appear in upcoming special issue "Orbital Angular Momentum" of the Journal of Optic

Una agenda internacional imBRICada: los nuevos caminos y desafíos de la política externa brasileña en el siglo XXI (Tema Central)

Este ensayo, de carácter analítico-descriptivo, pretende transitar entre las grandes líneas de la política exterior brasileña a lo largo de la primera década del siglo XXI, más específicamente durante los dos mandatos de Luiz Inácio Lula Da Silva (2003-2006 y 2007-2010), a fin de identificar en qué medida la agenda internacional brasileña fue afectada desde su categorización como potencia emergente bajo el acrónimo de BRIC (Brasil, Rusia, India y China) en el año 2003. El análisis parte de la premisa de que la política exterior brasileña, a lo largo de la primera década del siglo XXI, está más que nunca, imBRICada. Más allá de un simple juego de palabras, im“BRIC”ar significa dejar en evidencia la forma compleja en la que interactúan las diversas prioridades de la agenda internacional de un país emergente como Brasil, a veces convergiendo, a veces discrepando.The essay claims that Brazilian foreign policy, during the first decade of the 21st century, is more than ever, im“BRIC”ated. That is, Brazil’s foreign policy is immersed in a set of complex interactions with its new role as an emergent economic and political power. This complexity is made clear throughout the analysis of three major priorities of the Brazilian international agenda: the quest for a permanent seat at the United Nations Security Council, the leadership of South- South alliances and coalitions, and the priority of South-American integration. The authors argue that Brazil’s foreign policy decision-makers should be aware of the new complexities, and the challenges that they put forward for Brazil’s international actions, in particular for a Brazilian version of multilateralism

Scalability of GHZ and random-state entanglement in the presence of decoherence

We derive analytical upper bounds for the entanglement of generalized Greenberger-Horne-Zeilinger states coupled to locally depolarizing and dephasing environments, and for local thermal baths of arbitrary temperature. These bounds apply for any convex quantifier of entanglement, and exponential entanglement decay with the number of constituent particles is found. The bounds are tight for depolarizing and dephasing channels. We also show that randomly generated initial states tend to violate these bounds, and that this discrepancy grows with the number of particles.Comment: 9 pages, 3 figure

The Impact of American Petroleum Institute Certifications in Quality Management Systems: Analysis of API Spec Q1 and Q2 Certified Organizations

The present study aims to provide initial insight into the quality management system. More precisely, it describes whether and to what extent implementation of Quality Management System according to API Spec Q1 and/or Q2 can impact various companies in the oil and gas industry. A sample of international organizations is surveyed to understand how certifications affect organizational culture, passing through elements such as competitiveness, reputation, organizational performance, costs, and others. In addition to the certification itself, a rigorous and challenging process of implementation, review, restructuring is carried out, involving fundamental elements of the organization. During this stage, technical support becomes essential for a productive consolidation of the required requirements, and later, the improvement scenario is indispensable to maintain all the success factors in order to consolidate a quality management system within the organization. Thus, based on the findings, companies in the oil and gas segment may identify and reflect on the certification benefits to improve their approach to quality management systems, given the observations of managers and operational interviewees