Numerical Relativity Investigation of the Effects of Gravitational Waves
  on the Inhomogeneity of the Universe
  We numerically integrate the Einstein's equations for a spatially flat
Friedmann-Lemaire-Robertson-Walker (FLRW) background spacetime with a spatial
curvature perturbation and evolving primordial tensor perturbations using the
Einstein Toolkit. We find that although the primordial tensor perturbation
doesn't play an important role in the evolution of the overdensity produced by
the scalar perturbation, there is an obvious imprint left by the primordial
tensor perturbation on the distribution of the fractional density perturbation
in the nonlinear region. This imprint may be a possible probe of a
gravitational waves background in the future.
