Neutrino masses and cosmology with Lyman-alpha forest power spectrum

We present constraints on neutrino masses, the primordial fluctuation spectrum from inflation, and other parameters of the \u39bCDM model, using the one-dimensional Ly\u3b1-forest power spectrum measured by [1] from the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey (SDSS-III), complemented by Planck 2015 cosmic microwave background (CMB) data and other cosmological probes. This paper improves on the previous analysis by [2] by using a more powerful set of calibrating hydrodynamical simulations that reduces uncertainties associated with resolution and box size, by adopting a more flexible set of nuisance parameters for describing the evolution of the intergalactic medium, by including additional freedom to account for systematic uncertainties, and by using Planck 2015 constraints in place of Planck 2013. Fitting Ly\u3b1 data alone leads to cosmological parameters in excellent agreement with the values derived independently from CMB data, except for a weak tension on the scalar index ns. Combining BOSS Ly\u3b1 with Planck CMB constrains the sum of neutrino masses to 11 m\u3bd < 0.12 eV (95% C.L.) including all identified systematic uncertainties, tighter than our previous limit (0.15 eV) and more robust. Adding Ly\u3b1 data to CMB data reduces the uncertainties on the optical depth to reionization \u3c4, through the correlation of \u3c4 with \u3c38. Similarly, correlations between cosmological parameters help in constraining the tensor-to-scalar ratio of primordial fluctuations r. The tension on ns can be accommodated by allowing for a running dns/d ln k. Allowing running as a free parameter in the fits does not change the limit on 11 m\u3bd. We discuss possible interpretations of these results in the context of slow-roll inflation

Accidental Inflation from Kähler Uplifting

We analyze the possibility of realizing inflation with a subsequent dS vacuum in the K\'ahler uplifting scenario. The inclusion of several quantum corrections to the 4d effective action evades previous no-go theorems and allows for construction of simple and successful models of string inflation. The predictions of several benchmark models are in accord with current observations, i.e., a red spectral index, negligible non-gaussianity, and spectral distortions similar to the simplest models of inflation. A particularly interesting subclass of models are 'left-rolling' ones, where the overall volume of the compactified dimensions shrinks during inflation. We call this phenomenon 'inflation by deflation' (IBD), where deflation refers to the internal manifold. This subclass has the appealing features of being insensitive to initial conditions, avoiding the overshooting problem, and allowing for observable running $\alpha$ ~ 0.012 and enhanced tensor-to-scalar ratio $r$ ~ $10^{-5}$. The latter results differ significantly from many string inflation models