  We study the evolution of abelian $U(1)$ electromagnetic as well as
non-abelian $SU(2)$ gauge fields, in the presence of space-time oscillations.
Analysis of the time evolution of abelian gauge fields shows the presence of
parametric resonance in spatial modes. A similar analysis in the case of
non-abelian gauge fields, in the linear approximation, shows the presence of
the same resonant spatial modes. The resonant modes induce large fluctuations
in physical observables including those that break the $CP-$symmetry. We also
carry out time evolution of small random fluctuations of the gauge fields,
using numerical simulations in $2+1$ and $3+1$ dimensions. These simulations
help to study non-linear effects in the case of non-abelian gauge theories. Our
results show that there is an increase in energy density with the coupling, at
late times. These results suggest that gravitational waves may excite
non-abelian gauge fields more efficiently than electromagnetic fields. Also,
gravitational waves in the early Universe and from the merger of neutron stars,
black holes etc. may enhance $CP-$violation and generate an imbalance in chiral
charge distributions, magnetic fields etc.
