Consider the Yang-Mills theory for the gauge field strength 2-form F on a manifold M:
S=∫M(12tr(F∧∗F)+θtr(F∧F)).
Upon quantization there might occur additional ghost terms. The term proportional to θ I can write as a boundary term. I assume that the boundaries are only the 3-dimensional spaces at the initial time ti and the final time tf. By applying Gaussian Theorem I obtain:
∫Mtr(F∧F)=∫∂Mtr(A∧dA+23A∧A∧A)=CS(∂M,tf)−CS(∂M,ti).
Here, CS(∂M,t) is the Chern-Simons form for the 3-dim. space ∂M evaluated at time t. By computing the Partition function I obtain a sum over all Chern-Simons classes. This sum goes over different topologies of the gauge bundle. If I want to compute e.g.
<0|TAμ(tf)Aν(ti)|0>=Dμν
I have to sum over different large gauge transformations. Let D(Ξ)μν be the gauge boson Propagator if the gauge Transformation winds topologically in a way that is classified by Ξ∈π1(∂M) with the fundamental Group π. Then I would have
Dμν=∑Ξ∈π1(∂M)exp(iθ(CS(Ξ,tf)−CS(Ξ,ti)))D(Ξ)μν ?
If a gauge boson winds around the manifold it propagates a longer distance than on the direct wa without winding from one Point to a neighboring Point. Therefore, gauge boson Propagators depend on how they wind around the manifold. Is my idea right? Or are there any mistakes in my Derivation?