KKLT

What the term means here

A proposed construction of a de Sitter vacuum in three steps: stabilize complex-structure moduli with fluxes, stabilize the volume with non-perturbative effects into a supersymmetric anti-de Sitter minimum, then uplift that minimum to positive vacuum energy with an anti-D3-brane.

Why it matters to this question

KKLT is the reference construction of the entire field. Nearly every subsequent argument, on either side, is an argument about whether its uplift step survives scrutiny in the full ten-dimensional theory.

What this does not establish

That KKLT is a well-defined proposal does not establish that it produces a controlled de Sitter vacuum. Whether the anti-brane backreaction is singular in ten dimensions, and whether the four-dimensional effective description remains valid, is actively disputed. Defenders point to an explicit ten-dimensional analysis reproducing the four-dimensional result; critics argue integrated ten-dimensional equations obstruct the uplift.