Cosmological Model in 2d Dilaton Gravity

TL;DR

This paper explores (1+1)-dimensional cosmological models using CGHS-type dilaton gravity, classifying solutions including closed universe models with closed time-like curves and de Sitter-like universes, and discusses effects of inhomogeneity and quantum back-reaction.

Contribution

It introduces new cosmological solutions in 2D dilaton gravity and analyzes the impact of inhomogeneity and quantum effects on these models.

Findings

Discovery of a Misner-type universe with closed time-like curves

Identification of asymptotically de Sitter universe solutions

Analysis of quantum back-reaction effects on classical solutions

Abstract

We apply CGHS-type dilaton gravity model to (1+1)-dimensional cosmological situations. First the behavior of a compact 1-dimensional universe (i.e. like a closed string) is classified on the assumption of homogeneity of universe. Several interesting solutions are found, which include a Misner-type universe having closed time-like curves, and an asymptotically de Sitter universe first pointed out by Yoshimura. In the second half of this talk, we discuss the modification of the classical homogeneous solutions, considering inhomogeneity of classical conformal matters and also quantum back-reaction respectively. (An expanded version of the talk presented by T. Mishima at Yukawa Institute of Theoretical Physics workshop `Quantum Gravity' 24-27, November 1992.)