KKLTtype
KKLT-type constructions are a class of proposals in type IIB string theory for stabilizing all moduli and obtaining metastable de Sitter vacua in four dimensions. They rely on compactifications of orientifolded Calabi-Yau manifolds with background fluxes that generate a superpotential stabilizing the complex structure moduli and the dilaton. In these scenarios the flux superpotential W0 fixes the shape and coupling constants at a supersymmetric minimum, while the Kähler moduli remain unfixed at this stage. Non-perturbative effects, such as gaugino condensation on stacks of D7-branes or Euclidean D3-brane instantons, generate a non-perturbative contribution to the superpotential that stabilizes the overall volume modulus in an anti-de Sitter vacuum with N=1 supersymmetry.
To obtain a universe with a small positive cosmological constant, an anti-D3-brane is placed in a strongly
KKLT-type constructions have been influential in string phenomenology and cosmology as concrete mechanisms for moduli stabilization