Description
The low-energy limit of string theory contains additional gravitational degrees of freedom, which together with the metric are naturally embedded in the O(D,D)-symmetric framework of double field theory (DFT). Extending this O(D,D) symmetry to additional matter fixes a modified minimal coupling in string frame, while the resulting DFT energy-momentum tensor is enhanced to include dilaton pressure and skew-symmetric contributions. First I will review DFT cosmology and present some analytic solutions, including candidate bouncing cosmologies. Following this I will discuss perturbations, and I will explore the possibilities for structure formation and consistency with clustering observations.