A two-component picture of the <A^2> condensate with instantons

Understand

We study the interplay between the <A^2> condensate and instantons in non-Abelian gauge theory.

• Therefore we use the formalism of Local Composite Operators, with which the vacuum expectation value of this condensate can be analytically computed.
• We first use the dilute gas approximation and partially solve the infrared problem of instanton physics.
• In order to find quantitative results, however, we turn to an instanton liquid model, where we find how the different contributions to the condensate add up.