Types of quantum field thories
In physics, moduli stabilization refers to designing of models (in theoretical physics) that invoke the Kaluza-Klein mechanism (in order to obtain an effective QFT of gravity and gauge theory in low dimensions from a theory of gravity in higher dimensions) in a way such that the “moduli” fields that appear by the mechanism but which are unwanted in the model (since they do not correspond to observed fields) end up having high masses, so that the KK-model is consistent with observation at presently available energies (with the standard model of particle physics).
The issue arises notably in string theory Kaluza-Klein compactifications. In the context of type II string theory one way to design the model such that the moduli fields are massive is to consider the case where higher background gauge fields are present on the compactication space. Since these fields are characterized by their higher field strength/curvature forms which are referred to as “flux” terms in physics, these models are called flux compactification models.
Since for these flux compactifications only the periods of the form fields on the compact space matter, under a bunch of further assumptions on the nature of the compactification, one can reduce the number of possible such compactifications to a combinatorial problem. The resulting space of possibilities is also known as the landscape of string theory vacua.