Abstract

We prove the first law of black hole mechanics in the context of the Heterotic Superstring effective action compactified on a torus to leading order in α′, using Wald’s formalism, covariant Lie derivatives and momentum maps. The Kalb-Ramond field strength of this theory has Abelian Chern-Simons terms which induce Nicolai-Townsend transformations of the Kalb-Ramond field. We show how to deal with all these gauge symmetries deriving the first law in terms of manifestly gauge-invariant quantities. In presence of Chern-Simons terms, several definitions of the conserved charges exist, but the formalism picks up only one of them to play a role in the first law. We study explicitly a non-extremal, charged, black ring solution of pure mathcal{N} = 1, d = 5 supergravity embedded in the Heterotic Superstring effective field theory.This work is a first step towards the derivation of the first law at first order in α′ where, more complicated, non-Abelian, Lorentz (“gravitational”) and Yang-Mills Chern-Simons terms are included in the Kalb-Ramond field strength. The derivation of a first law is a necessary step towards the derivation of a manifestly gauge-invariant entropy formula which is still lacking in the literature. In its turn, this entropy formula is needed to compare unambiguously macroscopic and microscopic black hole entropies.

Highlights

  • This work is a first step towards the derivation of the first law at first order in α where, more complicated, non-Abelian, Lorentz (“gravitational”) and Yang-Mills ChernSimons terms are included in the Kalb-Ramond field strength

  • We prove the first law of black hole mechanics in the context of the Heterotic Superstring effective action compactified on a torus to leading order in α, using Wald’s formalism, covariant Lie derivatives and momentum maps

  • In a recent paper [27] we studied the use of gauge-covariant Lie derivatives in the context of the Einstein-Maxwell theory using momentum maps to construct the derivatives

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Summary

The Heterotic Superstring effective action on Tn at zeroth order in α

When the effective action of the Heterotic Superstring at leading order in α is compactified on a Tn, it describes the dynamics of the (10 − n)-dimensional (string-frame) metric gμν, Kalb-Ramond 2-form Bμν, dilaton field φ, Kaluza-Klein (KK) and winding 1-forms Amμ and Bm μ, respectively, and the scalars that parametrize the O(n, n)/O(n)×O(n) coset space, collected in the symmetric O(n, n) matrix M that we will write with upper O(n, n) indices I, J, . . . as M IJ. [27]), and calling the physical scalars in MIJ φx, the action of the d = (10 − n)-dimensional takes the form. In this action ea = eaμdxμ are the string-frame Vielbeins, stands for the Hodge dual and, (ea ∧ eb) =. The kinetic term of the scalars φx that parametrize the O(n, n)/(O(n)×O(n)) coset space can be written in the form. The equations of motion of the matter fields are given by EB = −d e−2φ H , Eφ = 8d e−2φ dφ −2L , EI.

Variations of the fields
Gauge transformations
Gauge charges
Diffeomorphisms and covariant Lie derivatives
The Wald-Noether charge
Zeroth laws
The first law
Discussion
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