Uplifting and inflation with D3 branes

Back-reaction effects can modify the dynamics of mobile D3 branes movingwithin type IIB vacua, in a way which has recently become calculable. Weidentify some of the ways these effects can alter inflationary scenarios, withthe following three results: (1) By examining how the forces on the brane dueto moduli-stabilizing interactions modify the angular motion of D3 branesmoving in Klebanov-Strassler type throats, we show how previous slow-rollanalyses can remain unchanged for some brane trajectories, while being modifiedfor other trajectories. These forces cause the D3 brane to sink to the bottomof the throat except in a narrow region close to the D7 brane, and do notameliorate the \eta-problem of slow roll inflation in these throats; (2) Weargue that a recently-proposed back-reaction on the dilaton field can be usedto provide an alternative way of uplifting these compactifications to Minkowskior De Sitter vacua, without the need for a supersymmetry-breaking anti-D3brane; and (3) by including also the D-term forces which arise whensupersymmetry-breaking fluxes are included on D7 branes we identify the 4Dsupergravity interactions which capture the dynamics of D3 motion in D3/D7inflationary scenarios. The form of these potentials sheds some light on recentdiscussions of how symmetries constrain D term interactions in the low-energytheory.Comment: JHEP.cls, 35 pages, 3 .eps figure