Go To Slide: 2001: A Spacetime Odyssey Title Simplest Model Initial Conditions Hybrid Inflation Pro and Contra Chaotic + Hybrid Inflation More generally General Conclusion Just Try It! Problems Solved Predictions Can we kill inflation? No vector perturbations best way to kill inflation What else...? Tachyonic Preheating The Main Idea graphs surface graphs more surface graphs craters volcanos Hybrid Inflation approximately correct The lesson Ekpyrotic Universe Postulates String Theorists Ask: General Relativists Ask: Horava-Witten Scenario Ekpyrotic 1 Ekpyrotic Scenario Pyrotechnic Universe Y vs V Density Perturbations initial requirement Problems Model Calculation of V(Y) problem with V(Y) Model Calculation of V(Y) problem with V(Y) the main problem... initial inhomogeneities Possible ways out One-brane stretching The Entropy Problem Ekpyrotic Universe