Topological Gravity as the Early Phase of Our Universe

Abstract

Motivated by string dualities we propose topological gravity as the early phase of our universe. The topological nature of this phase naturally leads to the explanation of many of the puzzles of early universe cosmology. A concrete realization of this scenario using Witten's four dimensional topological gravity is considered. This model leads to the power spectrum of CMB fluctuations which is controlled by the conformal anomaly coefficients $a,c$. In particular the strength of the fluctuation is controlled by $1/a$ and its tilt by $c{g}^2$ where $g$ is the coupling constant of topological gravity. The positivity of $c$, a consequence of unitarity, leads automatically to an IR tilt for the power spectrum. In contrast with standard inflationary models, this scenario predicts $\mathcal{O}(1)$ non-Gaussianities for four- and higher-point correlators and the absence of tensor modes in the CMB fluctuations.

27 pages, 3 figures

References in corpus (4)

• On the Geometry of the String Landscape and the Swampland
• String Gas Cosmology and Structure Formation
• T-Dual Cosmological Solutions of Double Field Theory II
• Inflation Free, Stringy Generation of Scale-Invariant Cosmological Fluctuations in D = 3 + 1 Dimensions

Cited by in corpus (8)

• Emergent Cosmology from Matrix Theory
• Cosmological consequences of a principle of finite amplitudes
• De Sitter Quantum Breaking, Swampland Conjectures and Thermal Strings
• Dark Radiation and the Hagedorn Phase
• de Sitter Complementarity, TCC, and the Swampland
• Limitations of an Effective Field Theory Treatment of Early Universe Cosmology
• Correspondence between the twisted $N=2$ super-Yang-Mills and conformal Baulieu-Singer theories
• Topological Early Universe Cosmology