7 research outputs found

    Planck 2013 results. XXII. Constraints on inflation

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    We analyse the implications of the Planck data for cosmic inflation. The Planck nominal mission temperature anisotropy measurements, combined with the WMAP large-angle polarization, constrain the scalar spectral index to be ns = 0:9603 _ 0:0073, ruling out exact scale invariance at over 5_: Planck establishes an upper bound on the tensor-to-scalar ratio of r < 0:11 (95% CL). The Planck data thus shrink the space of allowed standard inflationary models, preferring potentials with V00 < 0. Exponential potential models, the simplest hybrid inflationary models, and monomial potential models of degree n _ 2 do not provide a good fit to the data. Planck does not find statistically significant running of the scalar spectral index, obtaining dns=dln k = 0:0134 _ 0:0090. We verify these conclusions through a numerical analysis, which makes no slowroll approximation, and carry out a Bayesian parameter estimation and model-selection analysis for a number of inflationary models including monomial, natural, and hilltop potentials. For each model, we present the Planck constraints on the parameters of the potential and explore several possibilities for the post-inflationary entropy generation epoch, thus obtaining nontrivial data-driven constraints. We also present a direct reconstruction of the observable range of the inflaton potential. Unless a quartic term is allowed in the potential, we find results consistent with second-order slow-roll predictions. We also investigate whether the primordial power spectrum contains any features. We find that models with a parameterized oscillatory feature improve the fit by __2 e_ _ 10; however, Bayesian evidence does not prefer these models. We constrain several single-field inflation models with generalized Lagrangians by combining power spectrum data with Planck bounds on fNL. Planck constrains with unprecedented accuracy the amplitude and possible correlation (with the adiabatic mode) of non-decaying isocurvature fluctuations. The fractional primordial contributions of cold dark matter (CDM) isocurvature modes of the types expected in the curvaton and axion scenarios have upper bounds of 0.25% and 3.9% (95% CL), respectively. In models with arbitrarily correlated CDM or neutrino isocurvature modes, an anticorrelated isocurvature component can improve the _2 e_ by approximately 4 as a result of slightly lowering the theoretical prediction for the ` <_ 40 multipoles relative to the higher multipoles. Nonetheless, the data are consistent with adiabatic initial conditions

    Innovaci√≥n en las ense√Īanzas universitarias: experiencias presentadas en las III Jornadas de Innovaci√≥n Educativa de la ULL

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    En este libro se recoge un conjunto de experiencias de innovación educativa desarrolladas en la ULL en el curso 2011-12. Se abordan distintos ámbitos y ramas del conocimiento, y ocupan temáticas variadas que han sido desarrolladas con rigor, y con un claro potencial para su extrapolación a efectos de la mejora educativa en el ámbito universitario. Esta publicación constituye una primera edición de una serie que irá recogiendo las experiencias de innovación educativa de la ULL. Este es un paso relevante para su impulso en nuestra institución, como lo es el de su vinculación con la investigación educativa, para potenciar su publicación en las revistas científicas en este ámbito cada vez más pujante y relevante para las universidades. Sobre todo representan el deseo y el compromiso del profesorado de la ULL para la mejora del proceso educativo mediante la investigación, la evaluación y la reflexión compartida de nuestras prácticas y planteamientos docentes

    Harbors and Democracy

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