Cosmological Perturbations in Double Field Theory

Abstract

We explore perturbative double field theory about time-dependent (cosmological) backgrounds to cubic order. To this order the theory is consistent in a weakly constrained sense, so that for a toroidal geometry it encodes both momentum and genuine winding modes. We give a self-contained discussion of the consistency problems and their resolution, including the role of cocycle factors and the $O(d,d,\mathbb{Z})$ duality. Finally, as a first step toward the computation of cosmological correlation functions, we propose a generalized scalar-vector-tensor decomposition and use it to construct gauge invariant generalized Bardeen variables. Compared to standard cosmology there are fewer tensor modes but more vector and scalar modes.

34 pages

References in corpus (7)

• Double Field Theory
• Frame-like Geometry of Double Field Theory
• Wilsonian Effective Action of Superstring Theory
• Double Field Theory as the Double Copy of Yang-Mills
• New non-perturbative de Sitter vacua in ${\alpha }^{\prime }$-complete cosmology
• Solution of the Size and Horizon Problems from Classical String Geometry
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Cited by in corpus (3)

• 2D Black Holes, Bianchi I Cosmologies, and ${\alpha }^{\prime }$
• Perturbations in $\mathbf{O}(D,D)$ string cosmology from double field theory
• Black hole solutions in double field theory