4,324 research outputs found

    Non universality of entanglement convertibility

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    Recently, it has been suggested that operational properties connected to quantum computation can be alternative indicators of quantum phase transitions. In this work we systematically study these operational properties in 1D systems that present phase transitions of different orders. For this purpose, we evaluate the local convertibility between bipartite ground states. Our results suggest that the operational properties, related to non-analyticities of the entanglement spectrum, are good detectors of explicit symmetries of the model, but not necessarily of phase transitions. We also show that thermodynamically equivalent phases, such as Luttinger liquids, may display different convertibility properties depending on the underlying microscopic model.Comment: 5 pages + references, 4 figures - improved versio

    Localized states at zigzag edges of bilayer graphene

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    We report the existence of zero energy surface states localized at zigzag edges of bilayer graphene. Working within the tight-binding approximation we derive the analytic solution for the wavefunctions of these peculiar surface states. It is shown that zero energy edge states in bilayer graphene can be divided into two families: (i) states living only on a single plane, equivalent to surface states in monolayer graphene; (ii) states with finite amplitude over the two layers, with an enhanced penetration into the bulk. The bulk and surface (edge) electronic structure of bilayer graphene nanoribbons is also studied, both in the absence and in the presence of a bias voltage between planes.Comment: 4 pages, 5 figure

    Gender and politics: A descriptive and comparative analysis of the statutes of Brazilian and Portuguese political parties

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    This paper presents a descriptive and comparative analysis of the statutes of Brazilian and Portuguese political parties regarding women’s political participation. The main objective was to evaluate if and in what way women are included in the statutory guidelines. By means of the document analysis technique, we analyzed the statutes of political parties represented in the Chamber of Deputies in the case of Brazil and the Assembly of the Republic in the case of Portugal. Our research hypothesis is that although the explanatory potential of party ideology has declined as political parties from different positions on the spectrum have started to adopt discourses in favor of women’s political participation, left-wing parties remain more inclusive in their texts. We could observe that in both countries, leftist parties remain the main encouragers of women’s political participation, at least in their statutory rules.info:eu-repo/semantics/publishedVersio

    230102

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    Vehicle waiting time or stopped delay is one of the major disadvantages of employing signalized intersections (SIs) in road networks. The waiting time delays occur when vehicles stop in the queue, waiting to access the SI, and vary from road lane to road lane with the intersection management (IM) protocol used. In this research line, we propose an analytical expression for estimating the waiting time delays and studying the performance of different IM approaches in a grid network of independent intersections. We consider complex intersections with four legs and two lanes with two left-lane configurations, as well as five state-of-the-art IM approaches: two conventional -- Round-Robin (RR) and Trivial Traffic Light Control (TTLC); two adaptive -- Max-pressure Control Algorithm (MCA) and Websters Traffic Light Control (WTLC); and one reactive -- Synchronous Intersection Management Protocol (SIMP). The waiting time performance of these five IM approaches is compared using two simulation scenarios in the SUMO simulation framework. The simulation results validate the analytical study and show the advantages of employing SIMP, being the IM approach with the lowest waiting time delays.info:eu-repo/semantics/publishedVersio
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