Holography for the very early universe and the classic puzzles of hot big bang cosmology

Abstract

We show that standard puzzles of hot Big Bang cosmology that motivated the introduction of cosmological inflation, such as the smoothness and horizon problem, the flatness problem and the relic problem are also solved by holographic models for very early universe based on perturbative three dimensional QFT. In the holographic setup, cosmic evolution is mapped to inverse renormalization group (RG) flow of the dual QFT, and the resolution of the puzzles relies on properties of the RG flow. * horatiu.nastase@unesp.br † K.Skenderis@soton.ac.uk

Trans-Planckian censorship conjecture in holographic cosmology

“…In this scenario, TCC could constraint such "holographic reheating". Regardless, one can continue the relation (4) to the non-geometric phase in this class of models, in a similar fashion as the authors of [41] imposed the condition on the amount of RG flow in order to solve the flatness and horizon problems. In this case we would have a condition on the dual theory and once we have an explicit construction of a dual pair from String Theory, it would be interesting to investigate what this condition implies to or if it even can be derived from the stringy construction.…”

“…In this case, the super-Hubble modes of cosmological perturbation emerge from the non-geometrical phase through the transition between such period to usual Standard Cosmology and their spectra can be calculated from correlators in the dual field theory, that is local and well defined. As stressed in [41], the fact that the holographic dictionary is non-local explains how we could have correlation between super-Hubble scales even if there were no metric to define "causality" during the non-geometric phase.…”

“…which is just the Poincaré patch of Euclidean AdS. Following [41], the geodesic distance calculation gives L ∝ e −z . Thus, by using the domain wall/cosmology correspondence we get the following relation between distance scales in the dual QFT…”

Holographic cosmology solutions of problems with pre-inflationary cosmology

“…This framework is often assumed to be the only paradigm capable of describing JHEP12(2020)026 cosmology as a whole, including explaining the cosmic microwave background radiation (CMBR) and solving the cosmological problems of pre-inflationary cosmology. In this paper we will argue that the holographic models of [1], which describe a strongly interacting non-geometric very early Universe, are also capable of explaining both the CMBR observations and also resolving the classic puzzles of the hot Big Bang puzzles, elaborating on our discussion in [9],…”

“…Given this fact, a natural question to ask is what about the cosmological problems (Hot Big Bang puzzles) of pre-inflationary cosmology solved by inflation in [6][7][8]? We have found in [9] that the answer is, they are also solved, either in similar way, or in new ways. In this article we explain in detail the analysis of [9].…”