Lectures on the holographic duality of gauge fields and strings

This chapter gives a pedagogical review of the holographic duality between string theory and quantum field theory. The main focus is on the duality of maximally supersymmetric Yang–Mills gauge theory in four dimensions with string theory in asymptotically anti-de Sitter backgrounds. This duality is motivated using the large N expansion in the rank of the gauge group, as well as the D-brane solution for the AdS string theory background. The computation of Wilson loops on both sides of the duality is given as an example.