10,051 research outputs found

    Adiabatic pumping in the quasi-one-dimensional triangle lattice

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    We analyze the properties of the quasi-one-dimensional triangle lattice emphasizing the occurrence of flat bands and band touching via the tuning of the lattice hopping parameters and on-site energies. The spectral properties of the infinite system will be compared with the transmission through a finite piece of the lattice with attached semi-infinite leads. Furthermore, we investigate the adiabatic pumping properties of such a system: depending on the transmission through the lattice, this results in nonzero integer charge transfers or transfers that increase linearly with the lattice size

    Strange hadronic stellar matter within the Brueckner-Bethe-Goldstone theory

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    In the framework of the non-relativistic Brueckner-Bethe-Goldstone theory, we derive a microscopic equation of state for asymmetric and β\beta-stable matter containing Σ−\Sigma^- and Λ\Lambda hyperons. We mainly study the effects of three-body forces (TBFs) among nucleons on the hyperon formation and the equation of state (EoS). We find that, when TBFs are included, the stellar core is almost equally populated by nucleons and hyperons. The resulting EoS, which turns out to be extremely soft, has been used in order to calculate the static structure of neutron stars. We obtain a value of the maximum mass of 1.26 solar masses (1 solar mass Mo≃1.99⋅1033gM_o \simeq 1.99 \cdot 10^{33} g). Stellar rotations increase this value by about 12%.Comment: 4 pages, Latex, 2 figures included. To appear in the Proceedings of '' Bologna 2000 - Structure of the Nucleus at the Dawn of the Century'', May 29- June 3, 2000, Bologna, Ital

    Modelling linguistic taxonomic dynamics

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    This paper presents the results of the application of a bit-string model of languages (Schulze and Stauffer 2005) to problems of taxonomic patterns. The questions addressed include the following: (1) Which parameters are minimally ne eded for the development of a taxonomic dynamics leading to the type of distribution of language family sizes currently attested (as measured in the i number of languages per family), which appears to be a power-law? (2) How may such a model be coupled with one of the dynamics of speaker populations leading to the type of language size seen today, which appears to follow a log-normal distribution?Comment: 18 pages including 9 figure

    Direct Measurement of the g-Factor of Composite Fermions

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    The activation gap Δ\Delta of the fractional quantum Hall states at constant fillings ν=2/3\nu =2/3 and 2/5 has been measured as a function of the perpendicular magnetic field BB. A linear dependence of Δ\Delta on BB is observed while approaching the spin polarization transition. This feature allows a direct measurement of the gg-factor of composite fermions which appears to be heavily renormalized by interactions and strongly sensitive to the electronic filling factor.Comment: 4 pages, 4 figures Changed content: Fokus more on g-factors (and less on other details

    Structure of the hadron-quark mixed phase in protoneutron stars

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    We study the hadron-quark phase transition in the interior of hot protoneutron stars, combining the Brueckner-Hartree-Fock approach for hadronic matter with the MIT bag model or the Dyson-Schwinger model for quark matter. We examine the structure of the mixed phase constructed according to different prescriptions for the phase transition, and the resulting consequences for stellar properties. We find important effects for the internal composition, but only very small influence on the global stellar properties.Comment: 6 pages, 4 figure

    Calvyn en die Akademie van Geneve

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    In this article Calvin's founding of the College and Academy of Geneva (1559) is discussed against the background of the medieval school system in order to appreciate his part in the renewal of education. Imbibing the humanism of his day, Calvin's engagagement with education reveals common ground with the humanist ideals of his limes. Yet there were fundamental differences: by combining the classical artes liberates with the study of God’s Word, his ideal was not the creation of better human beings through education (the ideal of humanism) but the formation of useful men and women in the kingdom of God, i.e in church and society. Some stipulations of his church order (1541) and Leges for the Academy are placed in the context of his theology. Finally, Calvin’s ideals and contribution to education challenge us to consider our choices for education in a 'new South Africa’
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