A ΛCDM Bounce Scenario


Wilson-Ewing, E. (2015). A ΛCDM Bounce Scenario. Perimeter Institute. https://pirsa.org/15010074


Wilson-Ewing, Edward. A ΛCDM Bounce Scenario. Perimeter Institute, Jan. 21, 2015, https://pirsa.org/15010074


          @misc{ pirsa_PIRSA:15010074,
            doi = {10.48660/15010074},
            url = {https://pirsa.org/15010074},
            author = {Wilson-Ewing, Edward},
            keywords = {Quantum Gravity},
            language = {en},
            title = {A ΛCDM Bounce Scenario},
            publisher = {Perimeter Institute},
            year = {2015},
            month = {jan},
            note = {PIRSA:15010074 see, \url{https://pirsa.org}}

Edward Wilson-Ewing University of New Brunswick

Talk Type Scientific Series


We study a contracting universe composed of cold dark matter and radiation, and with a positive cosmological constant. Assuming that loop quantum cosmology captures the correct high-curvature dynamics of the space-time, we calculate the spectrum of scalar and tensor perturbations after the bounce, assuming initial quantum vacuum fluctuations. We find that the modes that exit the (sound) Hubble radius during matter-domination when the effective equation of state is slightly negative due to the cosmological constant will be nearly scale-invariant with a slight red tilt, in agreement with observations. The tensor perturbations are also nearly scale-invariant, and the predicted tensor-to-scalar ratio is small.  Finally, as this scenario predicts a positive running of the scalar index, it can be differentiated from inflationary models.