Time-dependent configurations in the perturbative formalism of string theory

TL;DR

This thesis explores exact time-dependent string configurations within the first-quantized formalism, enabling computation of perturbative amplitudes and insights into the interaction between dynamic geometries and quantum strings.

Contribution

It introduces a method to analyze exact time-dependent solutions in string theory and addresses technical challenges in perturbative computations.

Findings

Exact solutions of two-dimensional conformal field theory for time-dependent backgrounds

Perturbative string amplitudes can be computed in these configurations

Insights into the interaction between evolving geometries and quantum strings

Abstract

In this thesis time-dependent configurations are studied in the formalism of first-quantized string. These configurations are exact: solutions of the corresponding two-dimensional conformal field theory can be found. We can compute perturbative string amplitudes and try to understand the interplay between the time-dependent geometry and the quantized string. In a first chapter, we explain why we study these configurations. In a second chapter we describe the perturbative formalism and explain how to solve some of the technical problems we encountered. A third chapter is devoted to the physical description of the phenomena involved in these configurations, to the specific computations we made and to the insights we gained. Eventually, we conclude and give some perspectives.