Simple emergent power spectra from complex inflationary physics

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• Mafalda Dias (DESY)
• Monday 06 June 2016, 13:00-14:00
• CMS, Pav. B, CTC Common Room (B1.19) [Potter Room].

If you have a question about this talk, please contact Tommaso Giannantonio.

An ultraviolet-complete description of inflation may not be simple. Indeed, the large number of scalar fields appearing in the low energy effective description of string compactifications motivates the idea of inflation occurring on a complicated high-dimensional, essentially random, potential. It is far from clear that such scenarios are compatible with the simple observed primordial power spectrum, fully described by its amplitude and tilt. One might expect that the complicated dynamics occurring in such a potential would result in a highly non-linear spectrum. To address this question, two computational problems must be overcome, one at the level of the background and one regarding perturbations. In this talk I will describe how non-equilibrium random matrix theory can be used to solve both of these problems. As we will see, when the number of fields is small, the heavily featured potentials give rise to power spectra that are indeed highly non-linear. However, when the number of fields is large, the spectrum simplifies considerably and we find inflationary realisations with an approximately linear power spectrum. Hence, we provide proof of principle that complicated inflationary models as motivated by some string theory scenarios can be compatible with observation. I will also discuss how these simple power spectra can be interpreted as an emergent property of large N dynamics which can be understood in terms of the well known phenomenon of eigenvalue repulsion in random matrix theory.

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