Quantum / gauge field -> Classical limit

ansgar

Hello all quantum nerds! :D

I have a question regarding the "classical" limit of quantum fields, and in particular gauge fields.

When we for instance do a surface integration in QFT, we let phi -> 0 as V->oo

why? this is said in textbooks to correspond to the "classical limit",

and for gauge fields, one lets the field strength tensor F_mu,nu -> 0 which makes the gauge potential go to zero or a gauge transformation of 0.

So why these boundaries in the "classical" limit (V->oo)

Best regards