5,258 research outputs found

    Entanglement dynamics in open two-qubit systems via diffusive quantum trajectories

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    We use quantum diffusive trajectories to prove that the time evolution of two-qubit entanglement under spontaneous emission can be fully characterized by optimal continuous monitoring. We analytically determine this optimal unraveling and derive a deterministic evolution equation for the system's concurrence. Furthermore, we propose an experiment to monitor the entanglement dynamics in bipartite two-level systems and to determine the disentanglement time from a single trajectory.Comment: 4 pages, 2 figures, changed title, abstract and fig. 2, corrected typo

    A importância da atribuição do galardão de Reserva Mundial de Surf na Ericeira

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    A costa portuguesa é um recurso incomensurável graças à sua longa extensão, perfazendo um total de aproximadamente 1860 Km, distribuídos por Portugal Continental (943 Km), Arquipélago dos Açores (667 Km) e o Arquipélago da Madeira( 250Km). Esta singularidade dotou o país de uma oferta diversificada de produtos turísticos sendo o Sol e Mar, Cruzeiros e Turismo Náutico (desportos náuticos e atividades Marítimo-turísticas) um recurso turístico de aposta e uma nova área de negócio, aumentando a procura e/ou incentivando o investimento público/privado. Entre os vários desportos náuticos, destaca-se a importância que a modalidade de ondas (reconhecidas pela Internacional Surf Association – ISA como o Surf, o Bodyboard, o Longboard, o Kneebooard, o Tandem, o Skimboard, o Bodysurf, o Tow-in, o Tand up Paddle Surfe o Stand up Paddle Racing) tem ganho nos eixos Cascais-Estoril, Setúbal-Tróia e Ericeira-Nazaré-Peniche, reforçada com a atribuição do galardão de Reserva Mundial de Surf à Ericeira, no ano de 2011; a primeira da Europa e a Segunda do Mundo. Esta atribuição gerou uma nova dinâmica na economia local e regional, asseverando uma atratividade ao sector, ancorado numa estratégica comercial dirigida não só ao mercado internacional como também ao mercado interno, promovendo um conjunto de eventos relacionados quer com o desenvolvimento das potencialidades do território e ambiente (terra e mar), quer com a capacidade de inovação. Atrair investimento à região sob o mote da modalidade de ondas e estimular a procura (interna/externa) são cruciais para a economia local e a criação de emprego

    A ubiquidade e a contextualização no acesso à informação e serviços turísticos

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    Com a distinção da região do Alto Douro Vinhateiro a Património da Humanidade, na categoria de Paisagem Cultural, em dezembro de 2001, a região teve eco internacional, alcançando nova visibilidade. A natureza pristina convida o visitante a conhecer todo este património, transformando-o num recurso turístico que necessita de ser explicado e/ou interpretado (a história, as tradições, os artefactos, a arte, entre outros) de forma célere assente no pressuposto da ubiquidade de acesso à informação

    A location-based and contextualized mobile services approach to providing information and services in the tourism industry

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    Todays’ market is ruled by several mobile devices applications for all types of proposes. Still, for many destinations, it lacks applications that work in an integrated way, combining cooperative mechanisms that allow the effective support the wide range of tourists need when they visit a destination. Many applications, currently available, to the tourism industry are limited in content and cultural offerings, and commercial applications only communicate with their partners and have no cultural content. This paper presents a framework of a mobile application implementation to support the tourist information needs when tourists are visiting the Portuguese city of Mirandela in which interest points are combined with commercial content. The presented model allows the tourist to have only one application that integrates the contents that he wishes/subscribes, both cultural and commercial, creating a parametrizable universal profile that can be accessed by any of the entities in the system. This approach will benefit both tourists and entities involved. This will also allow increasing the dissemination of regional products and/or services and thereby increase their market potential and consequently their sales.UNIAG, R&D unit funded by the FCT – Portuguese Foundation for the Development of Science and Technology, Ministry of Science, Technology and Higher Education. UID/GES/4752/2019.info:eu-repo/semantics/publishedVersio

    A framework to support the tourist’s information-needs based on a ubiquitous approach

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    Nowadays, tourists are increasingly thirsty for information on anything that surrounds him. With the Information Communication Technologies (ICT) evolution that supports the ubiquity, it is necessary to rethink the available models of information and services to tourists. With the evolution of mobile devices, with wireless access, together with the decreasing of the network traffic costs and with the increasing number of access points of wireless access, becomes more common and attractive. Therefore, in this paper we present an analysis of the state of the art of the support applications for tourists for mobile environments, setting them according to the development technologies. In addition, it is also presented a suitable framework to support the tourist’s needs based on a ubiquitous approach

    Sustainable engineering labs - A Portuguese perspective

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    Strategies to reduce emissions responsible for greenhouse effect, and contributing to economy decarbonisation, should focus on using renewable energy, increasing energy efficiency both at production, distribution and consumption (equipment efficiency), sustainable mobility, urban renewal and rehabilitation and behavioural changes. Considering that man spend a significant part of their lives inside buildings that represent a significant share of energy consumption, buildings turn out to be an attractive area to invest efforts, aiming to improve efficiency, as recommended in the European Commission reports. However, despite the goals outlined in the Energy Performance of Buildings Directive, there are difficulties in the projection of new buildings that can be classified as nearly Zero Energy Buildings (nZEB). These include legal and financial obstacles, as insufficient formation of professionals (such as architects, engineers and consultants) able to tackle the challenges. This paper aims to point strategies that can contribute to the creation of a nearly zero energy laboratory in a university environment, that works as a tool for raising awareness about nZEB while improving the future engineering professionals’ skills towards team work and knowledge sharing – a living lab.info:eu-repo/semantics/publishedVersio

    Toward a test of angular momentum coherence in a twin-atom interferometer

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    We present a scheme well-suited to investigate quantitatively the angular momentum coherence of molecular fragments. Assuming that the dissociated molecule has a null total angular momentum, we investigate the propagation of the corresponding atomic fragments in the apparatus. We show that the envisioned interferometer enables one to distinguish unambiguously a spin-coherent from a spin-incoherent dissociation, as well as to estimate the purity of the angular momentum density matrix associated with the fragments. This setup, which may be seen as an atomic analogue of a twin-photon interferometer, can be used to investigate the suitability of molecule dissociation processes -- such as the metastable hydrogen atoms H(22S2^2 S)-H(22S2^2 S) dissociation - for coherent twin-atom optics.Comment: 6 pages, 3 Figures. Final version accepted for publication in Europhysics Letter

    A hora da virada

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