Bouncing alternatives to inflation

Patrick PETER
Institut d'Astrophysique de Paris (IAP)

Course Chapters Introduction: Shortcomings of inflation, why looking for alternatives Historical and critical review of models Old puzzles, new solutions Scale invariant perturbations Through the bounce Conclusion: Alternatives are still viable ... Abstract    Although inflation is, by far, the best known mechanism to explain the observed properties of our Universe, there is still some room for alternative models, most of which implying a contracting phase preceeding the current expanding one. Both phases are connected by a bounce at which the expansion rate must vanish. General relativity can only produce such a phase provided the spatial curvature is positive, in contradiction with the current observations. I will discuss the lines along which one can modify either the matter or the gravity sector (or both) in order to implement a bounce, and show the generic observable cosmological consequences it can induce, in particular in the microwave background. Bibliography Non inflationary model with scale invariant cosmological perturbations P. Peter, E. Pinho & N. Pinto-Neto,Phys. Rev. D 75, 023516 (2007) Cosmology without inflation P. Peter & N. Pinto-Neto, "", Phys. Rev. D 78, 063506 (2008) Bouncing Cosmologies M. Novello & S. E. Perez Bergliaffa, Phys. Rep. 463, 127 (2008) Conceptual problems of inflationary cosmology and a new approach to cosmological structure formation R. Brandenberger, in Inflationary cosmology, Lect. Notes Phys. 738, 393 (2008), Eds. M. Lemoine et al. Primordial cosmology P. Peter & J.-P. Uzan,  Oxford University Press (2009) Observing alternatives to inflation P. Peter, in "Cosmic structures and Evolution", arXiv:0912.1293 (2009)J. Lesgourgues and S. Pastor, Phys. Rept. 429: 307-379, 2006 [astro-ph/0603494]

Program