5 research outputs found

    Artificial gauge fields for the Bose-Hubbard model on a checkerboard superlattice and extended Bose-Hubbard model

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    We study the effects of an artificial gauge field on the ground-state phases of the Bose-Hubbard model on a checkerboard superlattice in two dimensions, including the superfluid phase and the Mott and alternating Mott insulators. First, we discuss the single-particle Hofstadter problem, and show that the presence of a checkerboard superlattice gives rise to a magnetic flux-independent energy gap in the excitation spectrum. Then, we consider the many-particle problem, and derive an analytical mean-field expression for the superfluid-Mott and superfluid--alternating-Mott insulator phase transition boundaries. Finally, since the phase diagram of the Bose-Hubbard model on a checkerboard superlattice is in many ways similar to that of the extended Bose-Hubbard model, we comment on the effects of magnetic field on the latter model, and derive an analytical mean-field expression for the superfluid-insulator phase transition boundaries as well.Comment: 8 pages, 5 figures and 1 table; to appear in EPJ

    The Physics of Star Cluster Formation and Evolution

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    © 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00689-4.Star clusters form in dense, hierarchically collapsing gas clouds. Bulk kinetic energy is transformed to turbulence with stars forming from cores fed by filaments. In the most compact regions, stellar feedback is least effective in removing the gas and stars may form very efficiently. These are also the regions where, in high-mass clusters, ejecta from some kind of high-mass stars are effectively captured during the formation phase of some of the low mass stars and effectively channeled into the latter to form multiple populations. Star formation epochs in star clusters are generally set by gas flows that determine the abundance of gas in the cluster. We argue that there is likely only one star formation epoch after which clusters remain essentially clear of gas by cluster winds. Collisional dynamics is important in this phase leading to core collapse, expansion and eventual dispersion of every cluster. We review recent developments in the field with a focus on theoretical work.Peer reviewe

    DIAGNÓSTICOS DE ENFERMAGEM DE PACIENTES INTERNADOS POR CARDIOPATIA CHAGÁSICA CRÔNICA

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    The undertaking of an interview and physical examination in 30 in-hospital chagasic chronic cardiopatic patients, taking in account the health functional patterns approach, led us to data for the making up the nursing diagnoses of these patients.A realização de entrevista e exame fĂ­sico de 30 pacientes internados por manifestaçÔes de cardiopatia chagĂĄsica crĂŽnica, utilizando a abordagem de padrĂ”es funcionais de saĂșde, forneceu dados para a formulação dos diagnĂłsticos de enfermagem desses pacientes

    Partially Ionized Plasmas in Astrophysics

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