Abstract:
We show that the gauge invariance of the operator$\int dx\,\operatorname{tr}(A_\mu^2-
2/(g\xi)x^\nu\theta_{\mu\nu}A^\mu)$ in a noncommutative gauge theory does not
lead to the gauge independence of its vacuum condensate. We obtain the generalized Ward identities for Green's functions containing the operator
$\lim_{\Omega\to\infty}(1/\Omega)\int_\Omega dx\,\operatorname{tr}(A_\mu^2)$ in commutative
and noncommutative gauge theories.
Keywords:vacuum condensates, noncommutative field theory, quantum chromodynamics, confinement phase.