New Insights into String Cosmology from Double Field Theory

Recent research by Stephen Angus and Shinji Mukohyama explores the implications of perturbations in ( \mathbf{O}(D,D) ) string cosmology through the lens of double field theory. Their paper, titled "Perturbations in ( \mathbf{O}(D,D) ) string cosmology from double field theory," presents a framework that integrates additional gravitational degrees of freedom, including a skew-symmetric tensor ( B )-field and a scalar dilaton, which are absent in general relativity.

The authors detail the equations of motion for linear perturbations around ( \mathbf{O}(D,D) ) string cosmological backgrounds in four dimensions. This study is significant as it provides analytic solutions for scalar perturbations in various homogeneous and isotropic background solutions, including models that suggest bouncing cosmologies.

One of the key findings is the introduction of a generalized energy-momentum tensor that incorporates source terms for the ( B )-field and dilaton. This modification leads to new conservation laws that alter the conditions necessary for the conservation of curvature perturbations. The results may have far-reaching implications for our understanding of the early universe and the dynamics of cosmological models.

This research contributes to the ongoing discourse in high-energy physics and cosmology, particularly in how string theory can provide insights into gravitational phenomena that deviate from conventional models. The full paper can be accessed at arXiv:2408.13032.