Towards a T-dual Emergent Gravity

TL;DR

This paper explores the relationship between emergent gravity and topological T-duality within the framework of generalized geometry, proposing a new geometric construction for T-duals of emergent gravity theories and analyzing their properties.

Contribution

It introduces a novel geometric approach to T-duality in emergent gravity using Courant algebroids and the Gualtieri-Cavalcanti map, extending the understanding of dualities in noncommutative and flux backgrounds.

Findings

T-dual of emergent gravity can be constructed via Courant algebroid isomorphisms.

In flat spacetime, T-dual of emergent gravity remains an emergent theory.

Formulas for T-dual metrics in $ ext{T}^2$-fibrations are derived, highlighting flux effects.

Abstract

Darboux theorem in symplectic geometry is the crux of emergent gravity in which the gravitational metric emerges from a noncommutative U(1)-theory. Topological T-duality, on the other hand, is a relation between two a priori different backgrounds (with different geometries, different fluxes and even topologically distinct manifolds) which nevertheless behave identically from a physical point of view. For us these backgrounds are principal torus bundles on the same base manifold. In this article we review how these theories can be naturally understood in the light of generalized geometry. Generalized geometry provides an unifying framework for such a systematic approach and gives rise to the group of Courant automorphism $Diff(M) \ltimes \Omega_{closed}^{2}(M)$ for the $TM \oplus T^*M$ bundle. Here we propose a novel geometric construction for the T-dual of an emergent gravity theory implemented between the $\mathbb{T}$-bundles and this duality is realized using the Gualtieri-Cavalcanti map that establishes an isomorphism between Courant algebroids. In the case of flat spacetime we obtain that, under mild assumptions, the T-dual of emergent gravity is again an emergent theory of gravity. In the general case we obtained formulas for the T-dual of an emergent metric in a $\mathbb{T}^2$-fibration, however due to the appearance of H-flux after T-dualizing, the theory thus obtained can no longer be considered in the usual framework of emergent gravity. This motivates the study of emergent gravity with non trivial H-flux.