Sigma model approach to string theory

TL;DR

This paper reviews how the sigma-model approach is used to derive effective equations of motion for massless fields in string theory, focusing on the tree-level approximation in closed bosonic strings.

Contribution

It provides a comprehensive overview of the sigma-model method applied to string theory's effective field equations at tree level.

Findings

Derivation of effective string equations of motion from sigma-models.

Clarification of the tree approximation in closed bosonic string theory.

Summary of the sigma-model approach's role in string theory.

Abstract

A review of the $\sigma$-model approach to derivation of effective string equations of motion for the massless fields is presented. We limit our consideration to the case of the tree approximation in the closed bosonic string theory.