981 resultados para Few-body systems


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Este estudo refere-se às evidências de necessidades de autocuidado de militares com hipertensão sistêmica da Marinha do Brasil. A hipertensão arterial é uma das doenças crônicas mais frequentes, de maior prevalência no mundo e a sua evolução leva a complicações que comprometem todos os sistemas orgânicos. Neste sentido o problema apresentado é: como se caracterizam as necessidades de autocuidado de militares hipertensos da Marinha do Brasil. Para tanto, o objetivo geral da pesquisa foi: Discutir as necessidades de cuidado no processo saúde/adoecimento do militar da Marinha do Brasil e os objetivos específicos: Descrever as características sociodemográficas e de autocuidado dos militares atendidos no ambulatório de cardiologia do HNMD; Identificar através dos depoimentos dos militares, as necessidades de autocuidado e; Propor estratégias de autocuidado em saúde aos militares. O referencial teórico utilizado foi o Modelo de Promoção de Saúde de Nola J Pender. Trata-se de um estudo misto de caráter exploratório e descritivo, realizado no ambulatório de Cardiologia do Hospital Naval Marcilio Dias, no município do Rio de Janeiro, no período de julho a agosto de 2014. Os sujeitos do estudo foram 20 militares hipertensos da Marinha do Brasil com idade acima dos 25 anos. Os dados foram coletados por meio de entrevista semiestruturada, em seguida, submetidos à análise de conteúdo de Bardin, emergindo três categorias e subcategorias assim denominadas: Primeira: Evidências de necessidades de autocuidado. Segunda: Identificação situacional da saúde dos militares com a subcategoria: A experiência do autocuidado para o militar com HAS. Terceira: Interesse pelo autocuidado com duas subcategorias: Interesse pelo aprendizado e Estratégias para o aprendizado do autocuidado. O perfil dos participantes caracterizou-se da seguinte maneira: Dos 20 militares, 19 são homens e 1 mulher, sendo 3 da ativa e 17 da reserva, a maioria são casados, idosos, de etnia parda e crença religiosa cristã, possuem ensino médio completo, com remuneração acima de 4 salários mínimos, residindo em local com saneamento básico. Quanto ao autocuidado referido pelos participantes: a maioria controla o uso de sal, ingesta hídrica adequada, utilizam alimentação balanceada, praticam algum tipo de exercício diário, a maioria referiu uso regular de anti-hipertensivos, e procura pelos serviços de saúde, quando necessário. Conclui-se que apesar do autocuidado referido, estes estão aquém às necessidades de saúde e não atendem às demandas de autocuidado necessária à manutenção da vida. Apesar de diversos fatores contribuírem para desmotivar os militares em relação ao autocuidado, eles apresentam interesse em aprender novas tecnologias de cuidar para adequação de sua saúde atual e melhora da qualidade de vida. Para atender às necessidades de autocuidado identificadas, sugere-se planejamento das ações estratégicas de promoção à saúde conjunta, com a equipe multiprofissional, instituindo a consulta de enfermagem, avaliação do autocuidado, prevenção dos fatores de risco e acompanhamento regular para análise das mudanças efetivas dos hábitos de vida saudáveis.

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The longitudinal momentum distribution (P-//) of fragments after one-proton removal from Al-23 and reaction cross sections (sigma(R)) for Al-23,Al-24 on carbon target at 74A MeV have been measured simultaneously. An enhancement in sigma(R) is observed for Al-23 compaxed with Al-24. The full width at half maximum of the P-// distribution for Mg-22 fragments has been determined to be 232 +/- 28 MeV/c. Analysis of P-// using the Few-Body Glauber Model indicates a dominant d-wave configuration for the valence proton in the ground state of Al-23. The exotic structure in Al-23 is discussed.

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We demonstrate that perfect state transfer can be achieved using an engineered spin chain and clean local end-chain operations, without requiring the initialization of the state of the medium nor fine-tuning of control pulses. This considerably relaxes the prerequisites for obtaining reliable transfer of quantum information across interacting-spin systems. Moreover, it allows us to shed light on the interplay among purity, entanglement, and operations on a class of many-body systems potentially useful for quantum information processing tasks.

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We introduce and formalize the concept of information flux in a many-body register as the influence that the dynamics of a specific element receive from any other element of the register. By quantifying the information flux in a protocol, we can design the most appropriate initial state of the system and, noticeably, the distribution of coupling strengths among the parts of the register itself. The intuitive nature of this tool and its flexibility, which allow for easily manageable numerical approaches when analytic expressions are not straightforward, are greatly useful in interacting many-body systems such as quantum spin chains. We illustrate the use of this concept in quantum cloning and quantum state transfer and we also sketch its extension to nonunitary dynamics.

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We describe the properties of a pair of ultracold bosonic atoms in a one-dimensional harmonic trapping potential with a tunable zero-ranged barrier at the trap center. The full characterization of the ground state is done by calculating the reduced single-particle density, the momentum distribution, and the two-particle entanglement. We derive several analytical expressions in the limit of infinite repulsion (Tonks-Girardeau limit) and extend the treatment to finite interparticle interactions by numerical solution. As pair interactions in double wells form a fundamental building block for many-body systems in periodic potentials, our results have implications for a wide range of problems.

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We study the changes in the spatial distribution of vortices in a rotating Bose-Einstein condensate due to an increasing eccentricity of the trapping potential. By breaking the rotational symmetry, the vortex system undergoes a rich variety of structural changes, including the formation of zigzag and linear configurations. These spatial rearrangements are well signaled by the change in the behavior of the vortex-pattern eigenmodes against the eccentricity parameter. This behavior allows to actively control the distribution of vorticity in many-body systems and opens the possibility of studying interactions between quantum vortices over a large range of parameters.

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We provide an extensive discussion on a scheme for Hamiltonian tomography of a spin-chain model that does not require state initialization [Phys. Rev. Lett. 102 ( 2009) 187203]. The method has spurred the attention of the physics community interested in indirect acquisition of information on the dynamics of quantum many-body systems and represents a genuine instance of a control-limited quantum protocol.

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We study quantum correlations in an isotropic Ising ring under the effects of a transverse magnetic field. After characterizing the behavior of two-spin quantum correlations, we extend our analysis to global properties of the ring, using a figure of merit for quantum correlations that shows enough sensitivity to reveal the drastic changes in the properties of the system at criticality. This opens up the possibility to relate statistical properties of quantum many-body systems to suitably tailored measures of quantum correlations that capture features going far beyond standard quantum entanglement.

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A report is presented of the XIIth International Workshop on Positron and Positronium Physics (Sandbjerg, Denmark, 19-21 July 2003). This workshop covered positron and positronium interactions with atoms, molecules and condensed matter systems. One key development reported was the first creation in the laboratory of low-energy antihydrogen atoms. Facets of positron-electron many-body systems were also considered, including the positronium molecule and BEC gases of positronium atoms. Aspects of the future of the field were discussed, including the development of new theoretical and experimental capabilities.

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The solution of the time-dependent Schrodinger equation for systems of interacting electrons is generally a prohibitive task, for which approximate methods are necessary. Popular approaches, such as the time-dependent Hartree-Fock (TDHF) approximation and time-dependent density functional theory (TDDFT), are essentially single-configurational schemes. TDHF is by construction incapable of fully accounting for the excited character of the electronic states involved in many physical processes of interest; TDDFT, although exact in principle, is limited by the currently available exchange-correlation functionals. On the other hand, multiconfigurational methods, such as the multiconfigurational time-dependent Hartree-Fock (MCTDHF) approach, provide an accurate description of the excited states and can be systematically improved. However, the computational cost becomes prohibitive as the number of degrees of freedom increases, and thus, at present, the MCTDHF method is only practical for few-electron systems. In this work, we propose an alternative approach which effectively establishes a compromise between efficiency and accuracy, by retaining the smallest possible number of configurations that catches the essential features of the electronic wavefunction. Based on a time-dependent variational principle, we derive the MCTDHF working equation for a multiconfigurational expansion with fixed coefficients and specialise to the case of general open-shell states, which are relevant for many physical processes of interest. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3600397]

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We perform an extensive study of the properties of global quantum correlations in finite-size one-dimensional quantum spin models at finite temperature. By adopting a recently proposed measure for global quantum correlations (Rulli and Sarandy 2011 Phys. Rev. A 84 042109), called global discord, we show that critical points can be neatly detected even for many-body systems that are not in their ground state. We consider the transverse Ising model, the cluster-Ising model where three-body couplings compete with an Ising-like interaction, and the nearest-neighbor XX Hamiltonian in transverse magnetic field. These models embody our canonical examples showing the sensitivity of global quantum discord close to criticality. For the Ising model, we find a universal scaling of global discord with the critical exponents pertaining to the Ising universality class.

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The entanglement spectrum describing quantum correlations in many-body systems has been recently recognized as a key tool to characterize different quantum phases, including topological ones. Here we derive its analytically scaling properties in the vicinity of some integrable quantum phase transitions and extend our studies also to nonintegrable quantum phase transitions in one-dimensional spin models numerically. Our analysis shows that, in all studied cases, the scaling of the difference between the two largest nondegenerate Schmidt eigenvalues yields with good accuracy critical points and mass scaling exponents.

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We study the entanglement distillability properties of thermal states of many-body systems Following the ideas presented in [6, A Ferraro et al., Phys. Rev Lett 100, 080502 (2008)], we first discuss the appearance of bound entanglement in those systems satisfying an entanglement area law Then, we extend these results to other topologies, not necessarily satisfying an entanglement area law We also study whether bound entanglement survives in the macroscopic limit of an infinite number of particles.