http://arxiv.org/abs/1408.0156
In a unified picture both inflation and present dynamical dark energy arise from the same scalar field. The history of the Universe describes a crossover from a scale invariant “past fixed point” where all particles are massless, to a “future fixed point” where spontaneous breaking of the exact scale symmetry generates the particle masses. The cosmological solution can be extrapolated to the infinite past in physical time – the universe has no beginning. This is seen most easily in a frame where particle masses and the Planck mass are field-dependent and increase with time. In this “freeze frame” the Universe shrinks and heats up during radiation and matter domination. In the equivalent, but singular Einstein frame cosmic history finds the familiar big bang description. The first stage of the crossover ends inflation. For the primordial fluctuations we find a spectral index $n\lesssim 0.967$ and a tensor amplitude $r\gtrsim 0.13$, with typical values close to the bounds. The crossover is completed by a second stage where a standard-model-singlet sector makes the transition to the future fixed point. The resulting increase of neutrino masses stops a cosmological scaling solution, relating the present dark energy density to the present neutrino mass. A simple model with no more free parameters than $\Lambda$CDM is compatible with all present observational tests.
C. Wetterich
Mon, 4 Aug 14
22/40
Comments: 21 pages, 3 figures
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