TASI Lectures on de Sitter Vacua

These lectures provide a self-contained introduction to flux compactifications of type IIB string theory on Calabi-Yau orientifolds. The first lecture begins with geometric foundations, then presents vacuum solutions in Calabi-Yau compactifications, as well as the geometry and physics of the moduli problem. The second lecture develops the classical theory of type IIB flux compactifications, both in ten dimensions and in the four-dimensional effective theory. The third lecture turns to the quantum theory of flux compactifications, including perturbative and non-perturbative corrections. With this foundation, in the fourth lecture we give a detailed treatment of the candidate de Sitter vacua recently constructed in arXiv:2406.13751. These notes are intended to be accessible to graduate students working in adjacent fields, and so extensive background material is included throughout.