Inflation in warped geometries

We argue that brane anti-brane inflation in string theory de-Sitter vacua of Kachru-Kallosh-Linde-Trivedi (KKLT) is captured by the dynamics of a D3-brane probe in the local KKLT model constructed in hep-th/0203041. This provides a framework to study in a controllable way corrections to the inflationary slow roll parameter eta due to conformal symmetry breaking in a warped geometry throat. We compute the leading correction to eta for the inflation in the Klebanov-Tseytlin throat geometry. We find that in certain regime this correction tends to decrease eta. Computations in a different regime suggest however that it is unlikely that eta much less than 1 can be achieved with the D3-brane throat inflation. (C) 2004 Elsevier B.V. All rights reserved.