Related papers: Gravitational waves from a curvaton model with blu…
The existence of a stochastic gravitational wave background is indicated by the recent pulsar timing array (PTA) experiments. We study the enhanced production of second-order gravitational waves from the scalar perturbations when the…
It is widely accepted that the primordial universe experienced a brief period of accelerated expansion called inflation. This scenario provides a plausible solution to the horizon and flatness problems. However, the particle physics…
Gravitational waves offer an unprecedented opportunity to look into the violent high-energy processes happening during the reheating phase of our Universe. We consider a Hubble-induced phase transition scenario as a source of a…
We investigate the second order gravitational waves induced by the primordial scalar and tensor perturbations during radiation-dominated era. The explicit expressions of the power spectra of the second order GWs are presented. We calculate…
We revisit the effects of an early matter-dominated era on gravitational waves induced by scalar perturbations. We carefully take into account the evolution of the gravitational potential, the source of these induced gravitational waves,…
Gravitational waves provide a novel way to probe axions or axion-like particles coupled to a dark photon field, even in the absence of couplings to Standard Model particles. In the conventional misalignment mechanism, the generation of an…
We investigate scalar-induced stochastic gravitational waves from adiabatic curvature perturbations sourced by a spectator field via the modulated reheating mechanism. We consider a spectator scalar with Higgs-like couplings and inflaton…
We study gravitational-wave production from bubble dynamics (bubble collisions and sound waves) during a cosmic first-order phase transition with an analytic approach. We first propose modeling the system with the thin-wall approximation…
Cosmological solitons are widely predicted by scenarios of the early Universe. In this work, we investigate the isotropic background and anisotropies of gravitational waves (GWs) induced by soliton isocurvature perturbations, especially…
We study the production of scalar-induced gravitational waves and primordial black holes in a single-field inflation model with a localized bump or dip feature in the potential. Introducing such a localized feature temporarily decelerates…
We investigate the first and second order cosmological perturbation equations in f(R) modified gravity theory and provide the equation of motion of second order scalar induced gravitational waves. We find that the effects of modified…
We investigate the generation of gravitational waves due to the gravitational instability of primordial density perturbations in an early matter-dominated era which could be detectable by experiments such as LIGO and LISA. We use…
Assuming that inflation is succeeded by a phase of matter domination, which corresponds to a low temperature of reheating $T_r<10^9\rm{GeV}$, we evaluate the spectra of gravitational waves induced in the post-inflationary universe. We work…
We calculate the gravitational waves (GW) spectrum produced in various Early Universe scenarios from gauge field sources, thus generalizing earlier inflationary calculations to bouncing cosmologies. We consider generic couplings between the…
During inflation long wavelength gravitational waves are produced, which form stochastic background in the present universe with very wide range of frequencies. Higher frequency gravitational waves never experience super-Hubble-radius…
Particles in a yet unexplored dark sector with sufficiently large mass and small gauge coupling may form purely gravitational atoms (quantum gravitational bound states) with a rich phenomenology. In particular, we investigate the…
Dark gauge fields have been discussed as candidates for dark matter recently. If they existed, primordial dark magnetic fields during inflation would have existed. It is believed that primordial gravitational waves (PGWs) arise out of…
We compute the stochastic gravitational wave production from Affleck-Dine condensate fragmentation in the early universe, focusing on an effective potential with a logarithmic mass correction that typically arises in gravity mediated…
The collapse of large-amplitude primordial curvature perturbations into planetary-mass primordial black holes generates a scalar-induced gravitational wave background in the $\mu $Hz frequency range that may be detectable by future Lunar…
Gravitational waves (GWs) generated by a first-order phase transition at the electroweak scale are detectable by future space-based detectors like LISA. The lifetime of the resulting shock waves plays an important role in determining the…