Compactification (physics) - Flux Compactification

A flux compactification is a particular way to deal with additional dimensions required by string theory. It assumes that the shape of the internal manifold is a Calabi–Yau manifold or generalized Calabi–Yau manifold which is equipped with non-zero values of fluxes, i.e. differential forms that generalize the concept of an electromagnetic field (see p-form electrodynamics).

The hypothetical concept of the anthropic landscape in string theory follows from a large number of possibilities in which the integers that characterize the fluxes can be chosen without violating rules of string theory. The flux compactifications can be described as F-theory vacua or type IIB string theory vacua with or without D-branes.