Nonlinear Sigma Model for String Solitons

TL;DR

This paper demonstrates that a renormalizable nonlinear sigma model can produce the effective string theory of Polchinski and Strominger, revealing massive world-sheet modes due to spontaneous conformal symmetry breaking in long string backgrounds.

Contribution

It establishes a connection between nonlinear sigma models and effective string theories, highlighting the emergence of massive modes from symmetry breaking.

Findings

Nonlinear sigma model reproduces Polchinski-Strominger effective string theory

Massive world-sheet degrees of freedom arise in long string backgrounds

Spontaneous conformal symmetry breaking leads to these massive modes

Abstract

It is shown that a renormalizable nonlinear sigma model gives rise to the effective string theory proposed by Polchinski and Strominger. In the presence of long string background, the model contains massive world-sheet degrees of freedom owing to the spontaneous breaking of conformal invariance.