19,979 research outputs found
Doped AB_2 Hubbard Chain: Spiral, Nagaoka and RVB States, Phase Separation and Luttinger Liquid Behavior
We present an extensive numerical study of the Hubbard model on the doped
AB chain, both in the weak coupling and the infinite-U limit. Due to the
special unit cell topology, this system displays a rich variety of phases as
function of hole doping () away from half-filling. Near half-filling,
spiral states develop in the weak coupling regime, while Nagaoka itinerant
ferromagnetism is observed in the infinite-U limit. For higher doping the
system phase-separates before reaching a Mott insulating phase of short-range
RVB states at . Moreover, for we observe a crossover,
which anticipates the Luttinger liquid behavior for .Comment: 11 pages, 13 figure
Magnetism and Electronic Correlations in Quasi-One-Dimensional Compounds
In this contribution on the celebration of the 80th birthday anniversary of
Prof. Ricardo Ferreira, we present a brief survey on the magnetism of
quasi-one-dimensional compounds. This has been a research area of intense
activity particularly since the first experimental announcements of magnetism
in organic and organometallic polymers in the mid 80s. We review experimental
and theoretical achievements on the field, featuring chain systems of
correlated electrons in a special AB2 unit cell structure present in inorganic
and organic compounds
Decoherence, pointer engineering and quantum state protection
We present a proposal for protecting states against decoherence, based on the
engineering of pointer states. We apply this procedure to the vibrational
motion of a trapped ion, and show how to protect qubits, squeezed states,
approximate phase eigenstates and superpositions of coherent states.Comment: 1 figur
Cultivos sucessivos de milho em várzea.
Visando obter informações sobre formas de cultivares de milho em várzeas, capazes de manter em uma mesma área elevadas produtividades por um perĂodo maior que o verificado atualmente, estao sendo avaliados cultivos sucessivos dessa espĂ©cie, atravĂ©s de ações de pesquisa executadas em várzea Ăşmida as margens do rio MazagĂŁo, municĂpio de MazagĂŁo, AP.bitstream/item/65117/1/AP-1997-cultivos-sucessivos-milho.pd
Seleção de clones promissores de cupuaçuzeiros para a implantação de pomares comerciais no Estado do Amapá.
bitstream/item/145486/1/CPAF-AP-2015-BPD-91-Cupuacu-v3-1.pd
Manejo de doenças do mamoeiro.
O mamoeiro Ă© afetado por um grande nĂşmero de doenças. As de maior importância econĂ´mica sĂŁo citadas a seguir: Viroses ? As viroses constituem o maior entrave Ă implantação da cultura do mamoeiro, por causa da dificuldade do seu controle e da necessidade de migração que elas impõem Ă essa cultura. As trĂŞs mais importantes sĂŁo: o vĂrus vĂrus-da-mancha-anelar do- mamoeiro, no Brasil conhecido como o mosaico-do-mamoeiro; o vĂrus-da-meleira; e o vĂrus-do-amarelo mamoeiro; vĂrus amarelo-letal.Curso
Seleção de matrizes promissoras de buriti (Mauritia flexuosa l.) no Amapá tendo em vista a produção de biocombustĂvel.
Resumo simples
Análise fĂsico-quĂmica de frutos de buriti (Mauritia flexuosa l.) provenientes de trĂŞs áreas nativas do Estado do Amapá, Brasil.
Generalized partition functions and interpolating statistics
We show that the assumption of quasiperiodic boundary conditions (those that
interpolate continuously periodic and antiperiodic conditions) in order to
compute partition functions of relativistic particles in 2+1 space-time can be
related with anyonic physics. In particular, in the low temperature limit, our
result leads to the well known second virial coefficient for anyons. Besides,
we also obtain the high temperature limit as well as the full temperature
dependence of this coefficient.Comment: 12 pages, Latex, updated and enlarged versio
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