The critical geometry of a thermal big bang
General Relativity and Quantum Cosmology
2016-11-23 v2 Cosmology and Nongalactic Astrophysics
High Energy Physics - Theory
Abstract
We explore the space of scalar-tensor theories containing two non-conformalmetrics, and find a discontinuity pointing to a "critical" cosmological solution. Due to the different maximal speeds of propagation for matter and gravity,the cosmological fluctuations start off inside the horizon even without inflation, and will more naturally have a thermal origin (since there is never vacuum domination). The critical model makes an unambiguous, non-tuned prediction for the spectral index of the scalar fluctuations: . Considering also that no gravitational waves are produced, we have unveiled the most predictive model on offer. The model has a simple geometrical interpretation as a probe 3-brane embedded in an geometry.
Keywords
Cite
@article{arxiv.1603.03312,
title = {The critical geometry of a thermal big bang},
author = {Niayesh Afshordi and Joao Magueijo},
journal= {arXiv preprint arXiv:1603.03312},
year = {2016}
}