Related papers: Anisotropies in the Gravitational Wave Background …
I review two mechanisms by which gravitational waves can be generated at the end of inflation: preheating, and gravitons Hawking radiated during the decay of very small primordial black holes. These mechanisms are contrasted with the…
We demonstrate the parametric amplification of the stochastic gravitational wave background during inflationary reheating and during axion/moduli oscillations. This amplification enhances the detectability of the string/inflationary gravity…
We compute the stochastic gravitational wave background sourced at second order by a spectator scalar field $\chi$ coupled to the inflaton $\phi$ through a portal interaction $\sigma\phi^2\chi^2$ and with quartic self-interaction…
Recent reports of stochastic gravitational wave background from four independent pulsar-timing-array collaborations have renewed the interest in the cosmological gravitational wave background (CGWB), which is expected to open a new window…
Could COBE DMR be detecting the imprint from a spectrum of gravitational waves generated during inflation? The conventional inflationary prediction had been that the cosmic microwave anisotropy is dominated by energy density fluctuations…
In this paper we propose a mechanism of natural preheating of our universe by introducing an inflaton field dependent mass term for the gravitational wave for a specific class of massive gravity theory. For any single field inflationary…
The existence of the Standard Model (SM) Higgs implies that a gravitational wave (GW) background is generated by the decay products of the Higgs, soon after the end of inflation. Theoretically, all Yukawa and $SU(2)_L$ gauge couplings of…
We discuss the influence of gravitational waves (GWs) upon the polarisation of the Cosmic Microwave Background Radiation (CMBR). We show how to compute the {\em rms} temperature anisotropy and polarisation of the CMBR induced by GWs of…
We construct a hybrid-inflation model where the inflaton potential is generated radiatively, as gauge symmetries guarantee it to be accidentally flat at tree level. The model can be regarded as a small-field version of Natural Inflation,…
The coupling between a pseudo-scalar inflaton and a gauge field leads to an amount of additional density perturbations and gravitational waves (GWs) that is strongly sensitive to the inflaton speed. This naturally results in enhanced GWs at…
Recently it was shown that an inflationary background can be realized by any $p$-form field non-minimally coupled to gravity. In this paper, we study gravitational waves generated during p-form inflation. Even though the background…
It is assumed that during inflation, all energy was contained in a slow-rolling inflaton field $\phi$. The particles constituting the Universe are created due to interactions with the field $\phi$ coherently oscillating after inflation. The…
We present three-dimensional direct numerical simulations of the production of magnetic fields and gravitational waves (GWs) in the early Universe during a low energy scale matter-dominated post-inflationary reheating era, and during the…
We study the evolution of gravitational waves through the preheating era that follows inflation. The oscillating inflaton drives parametric resonant growth of scalar field fluctuations, and although super-Hubble tensor modes are not…
Recent study [1] has suggested that warm inflation may be realized with a minimal extension of the Standard Model by a single scalar inflaton field with an axion-like coupling to gluons. Motivated by this framework, we investigate the…
Inflation with Weyl scaling symmetry provides a viable scenario that can generate both the nearly scaling invariant primordial density fluctuation and a dark matter candidate. Here we point out that, in additional to the primordial…
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…
The inflationary reheating phase begins when accelerated expansion ends. As all Standard Model particles are coupled to gravity, gravitational interactions will lead to particle production. This includes the thermal bath, dark matter and…
We study primordial gravitational waves (GWs) generated from first-order phase transitions (PTs) during cosmic reheating. Using a minimal particle physics model, and a general parametrization of the inflaton energy density and the evolution…
In the context of inflationary scenarios, the observed large angle anisotropy of the Cosmic Microwave Background (CMB) temperature is believed to probe the primordial metric perturbations from inflation. Although the perturbations from…