Uplifting and Inflation with D3 Branes

TL;DR

This work investigates how backreaction of a mobile D3 brane in type IIB flux compactifications modifies inflationary dynamics by incorporating F- and D-term corrections into a 4D supergravity framework. It computes explicit corrections to the nonperturbative superpotential via D7-brane backreaction, analyzes dilaton running and its potential to uplift AdS vacua without antibranes, and derives D-term contributions from SUSY-breaking fluxes on D7 branes, all within warped throat and orbifold geometries. The key findings are that (i) the angular part of the superpotential corrections vanishes at angular minima and cannot resolve the $\eta$-problem, (ii) the dilaton backreaction can uplift KKLT vacua to Minkowski/dS without antibranes, and (iii) D-term effects can be captured in a holomorphic gauge kinetic function framework and may contribute to uplifting in D3/D7 setups. Together, these results refine the viability and control of string-theoretic inflation models by clarifying the roles of backreaction and uplift mechanisms in the D3/D7 context and suggesting directions for constructing consistent D3/D7 inflationary scenarios.

Abstract

Back-reaction effects can modify the dynamics of mobile D3 branes moving within type IIB vacua, in a way which has recently become calculable. We identify some of the ways these effects can alter inflationary scenarios, with the following three results: (1) By examining how the forces on the brane due to moduli-stabilizing interactions modify the angular motion of D3 branes moving in Klebanov-Strassler type throats, we show how previous slow-roll analyses can remain unchanged for some brane trajectories, while being modified for other trajectories. These forces cause the D3 brane to sink to the bottom of the throat except in a narrow region close to the D7 brane, and do not ameliorate the η-problem of slow roll inflation in these throats; (2) We argue that a recently-proposed back-reaction on the dilaton field can be used to provide an alternative way of uplifting these compactifications to Minkowski or De Sitter vacua, without the need for a supersymmetry-breaking anti-D3 brane; and (3) by including also the D-term forces which arise when supersymmetry-breaking fluxes are included on D7 branes we identify the 4D supergravity interactions which capture the dynamics of D3 motion in D3/D7 inflationary scenarios. The form of these potentials sheds some light on recent discussions of how symmetries constrain D term interactions in the low-energy theory.