Scalar and fermion field interactions with a gravitational wave

Given that gravitational waves are the future probes of the Universe, it is important to test various physical effects of these on matter. This article explores the first-order perturbation, caused by a planar gravitational wave, on massless scalar and chiral fermions. We find a new propagating mode for the perturbed fields with a new dispersion relation by solving inhomogeneous differential equations. We also discuss the massive scalar field, and find interesting effects due to the gravitational wave. Our results have physical implications for early Universe cosmology and also for ground-based observations, where the new mode might be able to help in the gravitational waves' detection on Earth. (paper)