Dilatonic gravity near two dimensions as a string theory

TL;DR

This paper investigates a special sigma model of dilatonic gravity near two dimensions using renormalization-group methods, revealing fixed points and their properties within a string theory framework.

Contribution

It introduces a string parametrization of dilatonic gravity coupled to scalar fields and analyzes its fixed points near two dimensions.

Findings

Dilatonic gravity with scalar fields can be expressed as a sigma model with string parametrization.

The model possesses a usual UV fixed point.

The fixed point for scalar-dilaton coupling is trivial, while the gravitational coupling's fixed point remains non-trivial.

Abstract

Using the renormalization-group formalism, a sigma model of a special type- in which the metric and the dilaton depend explicitly on one of the string coordinates only-is investigated near two dimensions. It is seen that dilatonic gravity coupled to N scalar fields can be expressed in this form, using a string parametrization, and that it possesses the usual UV fixed point. However,in this stringy parametrization of the theory the fixed point for the scalar-dilaton coupling turns out to be trivial, while the fixed point for the gravitational coupling remains to be the same as in previous studies being, in particular, non-trivial.