Lorentzian Condition in Holographic Cosmology

TL;DR

This paper establishes specific conditions on the boundary theory in dS/CFT that ensure the prediction of classical Lorentzian bulk evolution, refining the criteria for classicality in holographic cosmology.

Contribution

It derives a set of boundary conditions in Euclidean dS/CFT that guarantee classical Lorentzian bulk evolution, using a canonical transformation approach.

Findings

Conditions are stronger than usual quantum cosmology criteria.

Explicit identification of classical histories in a minisuperspace model.

Sharpened formulation of dS/CFT correspondence.

Abstract

We derive a sufficient set of conditions on the Euclidean boundary theory in dS/CFT for it to predict classical, Lorentzian bulk evolution at large spatial volumes. Our derivation makes use of a canonical transformation to express the bulk wave function at large volume in terms of the sources of the dual partition function. This enables a sharper formulation of dS/CFT. The conditions under which the boundary theory predicts classical bulk evolution are stronger than the criteria usually employed in quantum cosmology. We illustrate this in a homogeneous isotropic minisuperspace model of gravity coupled to a scalar field in which we identify the ensemble of classical histories explicitly.