A Short Review of Time Dependent Solutions and Space-like Singularities in String Theory

TL;DR

This paper reviews the current understanding and challenges of time-dependent backgrounds with space-like singularities in string theory, discussing various approaches including BKL dynamics, worldsheet methods, and non-perturbative tools like AdS/CFT and M(atrix) theory.

Contribution

It provides a concise overview of different methods and efforts to analyze space-like singularities in string theory, highlighting the ongoing difficulties in forming a complete picture.

Findings

Various approaches have been explored to understand space-like singularities.

No fully satisfactory solution or understanding has yet been achieved.

The review summarizes progress and remaining challenges in the field.

Abstract

These lecture notes provide a short review of the status of time dependent backgrounds in String theory, and in particular those that contain space-like singularities. Despite considerable efforts, we do not have yet a full and compelling picture of such backgrounds. We review some of the various attempts to understand these singularities via generalizations of the BKL dynamics, using worldsheet methods and using non-perturbative tools such as the AdS/CFT correspondence and M(atrix) theory. These lecture notes are based on talks given at Cargese 06 and the dead-sea conference 06.