Holography for a Non-Inflationary Early Universe

TL;DR

This paper develops a holographic dual model for the pseudo-conformal universe, an alternative to inflation, by constructing five-dimensional domain-wall spacetimes with specific symmetries and analyzing their properties.

Contribution

It provides the first explicit holographic dual construction for the pseudo-conformal universe, including detailed calculations of scalar and stress-tensor expectation values.

Findings

Explicit domain-wall solutions with de Sitter symmetries

Holographic renormalization of scalar and stress-tensor

Connection to defect conformal field theories

Abstract

We construct a gravitational dual of the pseudo-conformal universe, a proposed alternative to inflation in which a conformal field theory in nearly flat space develops a time dependent vacuum expectation value. Constructing this dual amounts to finding five-dimensional domain-wall spacetimes with anti-de Sitter asymptotics, for which the wall has the symmetries of four-dimensional de Sitter space. This holographically realizes the characteristic symmetry breaking pattern O(2,4) to O(1,4) of the pseudo-conformal universe. We present an explicit example with a massless scalar field, using holographic renormalization to obtain general expressions for the renormalized scalar and stress-tensor one-point functions. We discuss the relationship between these solutions and those of four-dimensional holographic defect conformal field theories which break O(2,4) to O(2,3)