In this work, we shall exhaustively study the effects of modified gravity on the energy
spectrum of the primordial gravitational waves background. S. Weinberg has also produced …

We discuss the interpretation of the detected signal by pulsar timing array (PTA)
observations as a gravitational wave background of cosmological origin. We combine …

The NANOGrav pulsar timing array experiment reported evidence for a stochastic common-
spectrum process affecting pulsar timing residuals in its 12.5-yr data set, which might be …

The NANOGrav collaboration for the pulsar timing array (PTA) observation recently
announced evidence of an isotropic stochastic process, which may be the first detection of …

The symmetry breaking of grand unified gauge groups in the early Universe often leaves
behind relic topological defects such as cosmic strings, domain walls, or monopoles. For …

I review and discuss the possible implications for inflation resulting from considering new
physics in light of the Hubble tension. My study is motivated by a simple argument that the …

Recently, the pulsar timing array (PTA) collaborations have reported the evidence for a
stochastic gravitational wave background (SGWB) at nano-Hertz band. The spectrum of …

A stochastic gravitational wave background is a prediction of a number of astrophysical and
cosmological phenomena including early Universe cosmology. Recently, the NANOGrav …

We discuss the footprint of evaporation of primordial black holes (PBHs) on stochastic
gravitational waves (GWs) induced by scalar perturbations. We consider the case where …

We study gravitational waves induced from the primordial scalar perturbations at second
order around the reheating of the Universe. We consider reheating scenarios in which a …