Crunches, Hats, and a Conjecture

TL;DR

This paper examines the criteria and accuracy of dual descriptions for various cosmological models, including de Sitter and crunching FRW universes, assessing how precise these dualities can be.

Contribution

It analyzes the quality and potential exactness of existing dual descriptions for different cosmological backgrounds, building on recent discussions by Maldacena.

Findings

Dual descriptions for flat and AdS backgrounds are well-established.

Proposed duals for de Sitter and crunching FRW universes are likely approximate.

The paper evaluates the conditions under which these dualities can be considered exact.

Abstract

Our purpose in this paper is to discuss criteria for the existence of a precise dual description of a cosmology. A number of exact descriptions exist for flat and anti de Sitter backgrounds and possibly for open FRW universes that nucleate in an eternally inflating background. In addition duals have been proposed for de Sitter space, and for crunching FRW bubbles with negative cosmological constant. In the latter cases there is reason to think the dualities are at best approximate. One of our primary purposes is to analyze the quality of these descriptions, i.e., how exact they can be made. Maldacena's recent discussion of dualities involving crunching FRW cosmologies provides an opportunity for exploring some of these question.