Bouncing cosmology in a curved braneworld

We explore the possibility of a non-singular bounce in our universe from a warped braneworld scenario with dynamical branes and a non-zero brane cosmological constant. Such models naturally incorporate a scalar sector known as the radion originating from the modulus of the theory. The presence of brane cosmological constant renders the branes to be non-flat and gives rise to a potential and a non-canonical kinetic term for the radion field in the four dimensional effective action. The kinetic term exhibits a phantom-like behavior within the domain of evolution of the modulus which leads to a violation of the null-energy condition often observed in a bouncing universe. The interplay of the radion potential and kinetic term enables the evolution of the radion field from a normal to a phantom regime where the universe transits from a contracting era to an expanding epoch through a non-singular bounce. Analysis of the scalar and tensor perturbations over such background evolution reveal that the primordial observables e.g., the amplitude of scalar perturbations A(s), tensor to scalar ratio r and the scalar spectral index n(s) are in agreement with the current constraints reported by the Planck satellite. The implications are discussed.

Automated summary

This study investigates how the interaction between the radion potential and kinetic term in a warped braneworld scenario leads to the transition of the universe from a contracting to an expanding phase during a non-singular bounce. The analysis shows that the predicted primordial observables are consistent with the constraints reported by the Planck satellite.