The Poincare' coset models ISO(d-1,1)/R^n and T-duality

TL;DR

This paper extends Poincaré coset models to include symmetric terms, introduces gauge symmetries, and explores T-duality in string theory, resulting in new sigma-models describing strings in curved and degenerate space-times.

Contribution

It generalizes Poincaré coset models by incorporating symmetric terms and gauge symmetries, leading to new sigma-models with T-dual geometries.

Findings

Derived sigma-models describing strings in curved space-times.

Identified T-dual geometries for specific models.

Explicitly analyzed two non-degenerate cases.

Abstract

We generalize a family of Lagrangians with values in the Poincar\'e group ISO(d-1,1), which contain the description of spinning strings in flat (d-1)+1 dimensions, by including symmetric terms in the world-sheet coordinates. Then, by promoting a subgroup H=R^n, n less than or equal to d, which acts invariantly from the left on the element of ISO(d-1,1), to a gauge symmetry of the action, we obtain a family of sigma-models. They describe bosonic strings moving in (generally) curved, and in some cases degenerate, space-times with an axion field. Further, the space-times of the effective theory admit in general T-dual geometries. We give explicit results for two non degenerate cases.