The Cosmological Slingshot Scenario: a Stringy Proposal for the Early Time Cosmology

In The Cosmological Slingshot Scenario, our Universe is a $D3$‐brane that extends in the 4d noncompact directions of a warped Calabi‐Yau compactification of IIB Supergravity. Early time cosmology corresponds to a period in which the brane moves inside a warped throat, a non‐vanishing angular momentum ensuring that the trajectory of the brane has a turning point. The corresponding induced metric on the $D3$‐brane experiences a cosmological evolution with a bounce. In this framework, the homogeneity, flatness, and isotropy problems of standard cosmology might be avoided. The power spectrum of primordial perturbations of the brane embedding can be found and it is shown to be in agreement to WMAP data.