Black hole thermodynamics, stringy dualities and double field theory

TL;DR

This paper explores black hole thermodynamics within double field theory, deriving duality-invariant formulas for mass and entropy, and demonstrating their application to black fundamental strings and T-duals.

Contribution

It reformulates the first law of black hole thermodynamics in double field theory and provides explicit duality-invariant expressions for mass and entropy.

Findings

Derived duality-invariant mass and entropy formulas.

Reformulated the first law of black hole thermodynamics in DFT.

Applied results to black fundamental string solutions and T-duals.

Abstract

We discuss black hole thermodynamics in the manifestly duality invariant formalism of double field theory (DFT). We reformulate and prove the first law of black hole thermodynamics in DFT, using the covariant phase space approach. After splitting the full O(D, D) invariant DFT into a Kaluza-Klein-inspired form where only n coordinates are doubled, our results provide explicit duality invariant mass and entropy formulas. We illustrate how this works by discussing the black fundamental string solution and its T-duals.