PIRSA:11110119

Curvature and Anisotropy Near a Nonsingular Bounce

APA

Xue, B. (2011). Curvature and Anisotropy Near a Nonsingular Bounce. Perimeter Institute for Theoretical Physics. https://pirsa.org/11110119

MLA

Xue, BingKan. Curvature and Anisotropy Near a Nonsingular Bounce. Perimeter Institute for Theoretical Physics, Nov. 10, 2011, https://pirsa.org/11110119

BibTex

          @misc{ scivideos_PIRSA:11110119,
            doi = {10.48660/11110119},
            url = {https://pirsa.org/11110119},
            author = {Xue, BingKan},
            keywords = {Cosmology},
            language = {en},
            title = {Curvature and Anisotropy Near a Nonsingular Bounce},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2011},
            month = {nov},
            note = {PIRSA:11110119 see, \url{https://scivideos.org/pirsa/11110119}}
          }
          

BingKan Xue Princeton University

Talk numberPIRSA:11110119
Source RepositoryPIRSA
Talk Type Scientific Series
Subject

Abstract

Problematic growths of curvature and anisotropy are found in nonsingular bouncing cosmologies that include both an ekpyrotic phase and a bouncing phase. Classically, initial curvature and anisotropy that are suppressed during the ekpyrotic phase will grow back exponentially during the nonsingular bouncing phase. Besides, curvature and shear perturbations are generated by quantum fluctuations during the ekpyrotic phase. In the bouncing phase, an adiabatic curvature perturbation grows to dominate and gives rise to a blue spectrum that spoils the scale-invariance. Meanwhile, a scalar shear perturbation grows nonlinear and creates an overwhelming anisotropy that disrupts the nonsingular bounce altogether. We examine the common origin of these problems and discuss possible ways to avoid them.