137 research outputs found

    Magnetism And Phase Separation In Polymeric Hubbard Chains

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    We study a class of one-dimensional chains whose topology leads to flatbands in the electronic spectrum. Using the Hubbard model, we find that these materials should exhibit ferrimagnetic ordering for a half-filled band, in agreement with a theorem by Lieb. Away from half filling the system displays a very rich magnetic phase diagram. Possible experimental realizations are suggested.74101851185

    A simple model for magnetism in itinerant electron systems

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    A new lattice model of interacting electrons is presented. It can be viewed as a classical Hubbard model in which the energy associated to electron itinerance is proportional to the total number of possible electron jumps. Symmetry properties of the Hubbard model are preserved. In the half-filled band with strong interaction the model becomes the Ising model. The main features of the magnetic behavior of the model in the one-dimensional and mean-field cases are studied.Comment: 9 pages, 3 figures, to be published in Physica

    Recomendações Para O Tratamento Da Crise Migranosa - Um Consenso Brasileiro

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    In this article, a group of experts in headache management of the Brazilian Headache Society developed through a consensus strategic measurements to treat a migraine attack in both the child and the adult. Particular emphasis was laid on the treatment of migraine in women, including at pregnancy, lactation and perimenstrual period. © 2016, Associacao Arquivos de Neuro-Psiquiatria. All rights reserved.74326227
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