Black Holes and Naked Singularities in Low Energy Limit of String Gravity with Modulus Field

TL;DR

This paper investigates black hole solutions in low-energy string gravity with a modulus field, revealing they can have scalar hair and identifying bounds to prevent naked singularities.

Contribution

It demonstrates that string-inspired black holes can possess primary scalar hair and establishes bounds on scalar charges to avoid naked singularities.

Findings

Black holes can have primary scalar hair in string gravity.

Upper bounds on scalar charges prevent naked singularities.

One-loop effects influence black hole properties in string theory.

Abstract

We show that the black hole solutions of the effective string theory action, where one-loop effects that couple the moduli to gravity via a Gauss-Bonnet term are taken into account, admit primary scalar hair. The requirement of absence of naked singularities imposes an upper bound on the scalar charges.