  In quantum chromodynamics with static quarks the confinement-deconfinement
phase transition is connected to the spontaneous breaking of the global Z3
center symmetry. This symmetry is lost when one considers dynamical quarks.
Owing to the fractional electric charge of quarks, we recover a global Z6
center symmetry when QCD is regarded as a part of the Standard Model. We
present results from QCD-like theories extended by electromagnetic interactions
and show that the weak coupling limit of the QED part of the model results in a
center-like symmetry with disorder in the vacuum. This can be seen explicitly
in a character expansion of the fermion determinant. Further, we show that
corresponding center averages project the fermion determinant on N-ality zero
and discuss whether the additional center symmetry can be used to eliminate the
fermion sign problem in QCD with fundamental quarks.
