2004/12/06 by Matthew Kleban, Kleban, Matthew
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Theory (hep-th) #hep-th
paper · pdf · doi:10.48550/arxiv.hep-th/0412055
4 pages, 2 figs, prepared for the Proceedings of the Cargese Summer School 2004
arxiv created 2004/12/06 · arxiv updated 2009/12/01
I present a brief review of astro-ph/0406099, which argues that there is a limit on the number of efolds of inflation which are observable in a universe which undergoes an eternally accelerated expansion in the future. Such an acceleration can arise from an equation of state p = w ρ, with w < -1/3, and it implies the existence of event horizons. In some respects the future acceleration acts as a second period of inflation, and "initial perturbations" (including signatures of the first inflationary period) are inflated away or thermalize with the ambient Hawking radiation. Thus the current CMB data may be looking as far back in the history of the universe as will ever be possible even in principle, making our era a most opportune time to study cosmology.