De Sitter String Vacua from Dilaton-dependent Non-perturbative Effects

TL;DR

The paper extends the LVS framework by incorporating dilaton-dependent non-perturbative effects arising from D3-branes or E(-1)-instantons at singularities. This yields a positive, tunable uplift from F-terms of a blow-up mode, allowing fully supersymmetric de Sitter vacua and enabling LVS realizations for zero or positive Euler number manifolds when combined with string-loop corrections. The work also discusses how the uplift can be tuned via fluxes to achieve a discretuum of small cosmological constants and outlines the resulting phenomenological implications for inflation and soft supersymmetry breaking. Overall, the approach provides a robust, supersymmetric alternative to anti-D3-brane uplifts and broadens the landscape of LVS-compatible de Sitter constructions.

Abstract

We consider a novel scenario for modulus stabilisation in IIB string compactifications in which the Kahler moduli are stabilised by a general set-up with two kinds of non-perturbative effects: (i) standard Kahler moduli-dependent non-perturbative effects from gaugino condensation on D7-branes or E3-instantons wrapping four-cycles in the geometric regime; (ii) dilaton-dependent non-perturbative effects from gaugino condensation on space-time filling D3-branes or E(-1)-instantons at singularities. For the LARGE Volume Scenario (LVS), the new dilaton-dependent non-perturbative effects provide a positive definite contribution to the scalar potential that can be arbitrarily tuned from fluxes to give rise to de Sitter vacua. Contrary to anti D3-branes at warped throats, this term arises from a manifestly supersymmetric effective action. In this new scenario the "uplifting" term comes from F-terms of blow-up modes resolving the singularity of the non-perturbative quiver. We discuss phenomenological and cosmological implications of this mechanism. This set-up also allows a realisation of the LVS for manifolds with zero or positive Euler number.