http://arxiv.org/abs/1811.01994
We investigate if the observed small and nearly scale-invariant primordial cosmic perturbation, i.e. the perturbation amplitude $P_\zeta\sim10^{-9}$ and the spectral index $n_s \simeq 0.965$, is typical in the landscape of vacua after imposing anthropic selections on them. We consider the situation where the universe begins from a metastable vacuum driving a precedent inflation, a curvature-dominated open universe is created by tunneling, and the curvature energy is inflated away by new inflation. We argue that the initial inflaton field value is homogeneous but typically non-zero because of the quantum fluctuation of long wavelength modes created during the precedent inflation, and only the universe which accidentally has a small inflaton field value is anthropically selected. We show that this bias, together with certain distributions of inflation model parameters that are physically well-motivated, makes the observed small and nearly scale-invariant spectrum typical.
C. Chiang and K. Harigaya
Wed, 7 Nov 18
79/94
Comments: 16+10 pages, 14 figures
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