The Unresolved Land Reform Debate: Beyond State-Led or Market-Led Models

Land Reform; Debate; State-Led; Market-Led; Model

Detecting entanglement of two electron spin qubits with witness operators

We propose a scheme for detecting entanglement between two electron spin qubits in a double quantum dot using an entanglement witness operator. We first calculate the optimal configuration of the two electron spins, defined as the position in the energy level spectrum where, averaged over the nuclear spin distribution, 1) the probability to have two separated electrons, and 2) the degree of entanglement of the quantum state quantified by the concurrence are both large. Using a density matrix approach, we then calculate the evolution of the expectation value of the witness operator for the two-spin singlet state, taking into account the effect of decoherence due to quantum charge fluctuations modeled as a boson bath. We find that, for large interdot coupling, it is possible to obtain a highly entangled and robust ground state.Comment: 4 pages, 3 figure

Entanglement and the Quantum Brachistochrone Problem

Entanglement is closely related to some fundamental features of the dynamics of composite quantum systems: quantum entanglement enhances the "speed" of evolution of certain quantum states, as measured by the time required to reach an orthogonal state. The concept of "speed" of quantum evolution constitutes an important ingredient in any attempt to determine the fundamental limits that basic physical laws impose on how fast a physical system can process or transmit information. Here we explore the relationship between entanglement and the speed of quantum evolution in the context of the quantum brachistochrone problem. Given an initial and a final state of a composite system we consider the amount of entanglement associated with the brachistochrone evolution between those states, showing that entanglement is an essential resource to achieve the alluded time-optimal quantum evolution.Comment: 6 pages, 3 figures. Corrected typos in Eqs. 1 and

Jensen Shannon divergence as a measure of the degree of entanglement

The notion of distance in Hilbert space is relevant in many scenarios. In particular, distances between quantum states play a central role in quantum information theory. An appropriate measure of distance is the quantum Jensen Shannon divergence (QJSD) between quantum states. Here we study this distance as a geometrical measure of entanglement and apply it to different families of states.Comment: 5 pages, 2 figures, to appear in the special issue of IJQI "Noise, Information and Complexity at Quantum Scale", eds. S. Mancini and F. Marcheson

Towards Understanding the Politics of Flex Crops and Commodities: Implications for Research and Policy Advocacy

This discussion paper offers a preliminary exploration of the concept and phenomenon of “flex crops and commodities”, building on an earlier and initial analysis and abbreviated idea put forward by some of the authors of this paper. We discuss the dual concepts of the “multiple-ness” and “flexible-ness” of crops and commodities as two distinct but intertwined dimensions of some key crops and commodities. These key crops and commodities are shaped by the changing global context that is itself (re)moulded in large part by the convergence of multiple crises and the various responses to those crises. Building on these dual concepts, we will identify and explain the minimum requirements for crop and commodity flexing. We will also try to typologize the various types of crop and commodity flexing, namely, “real flexing”, “anticipated/speculated flexing”, and “imagined flexing”—to allow for a deeper examination of these interrelated processes. The boundaries between these categories (multiple/flexible, real, anticipated and imagined) are not always clearly demarcated, requiring us to examine the issue of flex crops and commodities in a more interlinked manner. We will focus our initial exploration on the political dynamics of such interactions and intersections, looking into the factors that encourage or discourage, facilitate or hinder maximization of the “multiple-ness” and/or “flexible-ness” of particular crops and commodities. Finally, and as a way of closing, we will outline the implications of these dynamics for how we think of engaged research, public actions and policy advocacy, including a brief discussion of what we call “flex policy narratives” by governments and corporations.

Disseny i elaboració de material docent per a l'aprenentatge autònom de les habilitats de pràctica clínica profesional de la matèria d'optometria

Peer Reviewe

The Politics of Governance Architectures: Creation, Change and Effects of the EU Lisbon Strategy

Governance architectures are strategic and long-term institutional arrangements of international organisations exhibiting three features, namely, they address strategic and long-term problems in a holistic manner, they set substantive output-oriented goals, and they are implemented through combinations of old and new organizational structures within the international organisation in question. The Lisbon Strategy is the most high-profile initiative of the European Union for economic governance of the last decade. Yet it is also one of the most neglected subjects of EU studies, probably because not being identified as an object of study on its own right. We define the Lisbon strategy as a case of governance architecture, raising questions about its creation, evolution, and impact at the national level. We tackle these questions by drawing on institutional theories about emergence and change of institutional arrangements and on the multiple streams model. We formulate a set of propositions and hypotheses to make sense of the creation, evolution and national impact of the Lisbon Strategy. We argue that institutional ambiguity is used strategically by coalitions at the EU and national level in (re-)defining its ideational and organisational elements

El desarrollo de la atención multidisciplinar en la atención al cáncer

En el contexto de la llamada lucha contra el cáncer, la organización de los servicios sanitarios no resultó ser un objetivo europeo hasta 2007, con la Presidencia portuguesa del Consejo Europeo y tras la constatación de que las diferencias en supervivencia relativa entre países europeos debían atribuirse en parte a la organización y la calidad en la provisión de servicios. La prioridad establecida por el marco europeo focaliza con especial énfasis la atención multidisciplinar, un modelo organizativo que conlleva una redistribución de competencias y responsabilidades en torno a los profesionales con mayor potencial en el logro de la efectividad clínica. La visión europea que surge tras el esfuerzo en investigación y consenso sobre el rol y los objetivos que deben asumir los equipos de atención multidisciplinar es determinante en la configuración del modelo de atención actual, más integrado y mayormente capaz de responder a los retos de la creciente complejidad que presenta la atención al cáncer

Efficient generation of random multipartite entangled states using time optimal unitary operations

We review the generation of random pure states using a protocol of repeated two qubit gates. We study the dependence of the convergence to states with Haar multipartite entanglement distribution. We investigate the optimal generation of such states in terms of the physical (real) time needed to apply the protocol, instead of the gate complexity point of view used in other works. This physical time can be obtained, for a given Hamiltonian, within the theoretical framework offered by the quantum brachistochrone formalism. Using an anisotropic Heisenberg Hamiltonian as an example, we find that different optimal quantum gates arise according to the optimality point of view used in each case. We also study how the convergence to random entangled states depends on different entanglement measures.Comment: 5 pages, 2 figures. New title, improved explanation of the algorithm. To appear in Phys. Rev.