BRANE–ANTIBRANE INFLATION

Inflationary cosmology has become central to our understanding of the initial conditions on whose foundations the current successes of the Hot Big Bang model rest. This is despite the well-known difficulties in finding systems whose dynamics naturally provide all of the features which successful inflation demands. Although string theory provides our best description of the physics of the relevant energy scales, it has only recently begun to shed insight into what the inflationary dynamics might be: the physics of brane-antibrane collisions. This essay is meant to summarize the difficulties which have blocked this realization until now, as well as the new insights about inflation which are now beginning to emerge.