O(n,n) invariance and Wald entropy formula in the Heterotic Superstring effective action at first order in alpha'

TL;DR

This paper derives an O(n,n)-invariant form of the Heterotic Superstring effective action at first order in alpha' and uses it to compute the Wald entropy of corrected black holes, revealing symmetry properties in string theory.

Contribution

It introduces a manifestly O(n,n)-invariant formulation of the effective action and entropy calculation for heterotic string black holes at first order in alpha'.

Findings

Derived an O(n,n)-invariant effective action at first order in alpha'

Established a Wald entropy formula respecting O(n,n) symmetry

Computed the entropy of alpha'-corrected extremal black holes

Abstract

We perform the toroidal compactification of the full Bergshoeff-de Roo version of the Heterotic Superstring effective action to first orderin $\alpha'$. The dimensionally-reduced action is given in a manifestly-O(n,n)-invariant form which we use to derive a manifestly-O(n,n)-invariant Wald entropy formula which we then use to compute the entropy of $\alpha'$-corrected, 4-dimensional, 4-charge, static, extremal, supersymmetric black holes.