The inflationary brane-antibrane universe

We show how the motion through the extra dimensions of a gas of branes and antibranes can, under certain circumstances, produce an era of inflation as seen by observers trapped on a 3-brane, with the inflaton being the inter-brane separation. Although most of our discussion refers to arbitrary ps, when we need to be specific we assume that they are D-branes of type-II or type-I string theory. For realistic brane couplings, such as those arising …