Related papers: Primordial gravitational waves amplification from …
We study a new class of inflation model parametrized by the Hubble radius, such that $aH\propto \exp(-k\phi^n)$. These potentials are plateau-like, and reduce to the power-law potentials in the simplest case $n=2$. We investigate the range…
In many models of inflation, the period of accelerated expansion ends with preheating, a highly non-thermal phase of evolution during which the inflaton pumps energy into a specific set of momentum modes of field(s) to which it is coupled.…
In this paper we study the behaviour of gravitational wave background (GWB) generated during inflation in the environment of the noncommutative field approach. From this approach we derive out one additive term, and then we find that the…
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 transition from an early matter dominated era to the radiation…
We consider the space-condensate inflation model to study the primordial gravitational waves generated in the early Universe. We calculate the energy spectrum of gravitational waves induced by the space-condensate inflation model for full…
In this paper, we revisit the estimation of the spectrum of primordial gravitational waves originated from inflation, particularly focusing on the effect of thermodynamics in the Standard Model of particle physics. By collecting recent…
We derive in detail the equations of motion for the tensorial modes of primordial metric perturbations in the Coupled-Scalar-Tachyon Bounce Universe. We solve for the gravitational wave equations in the pre-bounce contraction and the…
Gravitational waves in the presence of a non-minimal curvature-matter coupling are analysed, both in the Newman-Penrose and perturbation theory formalisms. Considering a cosmological constant as a source, the non-minimally coupled…
Large excursion of the inflaton field can trigger interesting dynamics. One important example is a first-order phase transition in a spectator sector which couples to the inflaton. Gravitational waves (GWs) from such a first-order phase…
We re-examine the decoherence rate of primordial fluctuations within minimal inflationary models, using only the gravitational interactions required for the underlying fluctuation-generation mechanism itself. Since gravity provides the…
The reheating of the universe after hybrid inflation proceeds through the nucleation and subsequent collision of large concentrations of energy density in the form of bubble-like structures moving at relativistic speeds. This generates a…
We study cosmological gravitational waves generated during inflation under the influence of a decaying cosmological "constant", in the Transverse-Traceless (TT) gauge. In our approach we consider a non-perturbative contribution of the…
Primordial gravitational waves provide a very important stochastic background that could be detected soon with interferometric gravitational wave antennas or indirectly via the induced patterns in the polarization anisotropies of the cosmic…
Gravitational waves were copiously produced in the early Universe whenever the processes taking place were sufficiently violent. The spectra of several of these gravitational wave backgrounds on subhorizon scales have been extensively…
We report on the first 3-dimensional numerical simulations of first-order phase transitions in the early universe to include the cosmic fluid as well as the scalar field order parameter. We calculate the gravitational wave (GW) spectrum…
We study the back-reaction of gravitational waves in early universe cosmology, focusing both on super-Hubble and sub-Hubble modes. Sub-Hubble modes lead to an effective energy density which scales as radiation. Hence, the relative…
The detection of primordial gravitational waves would offer a direct evidence of inflation and valuable insights into the dynamics of the early universe. During post-inflation reheating period, when the inflaton coherently oscillates at the…
The signal strength of primordial gravitational waves experiencing an epoch of early scalar domination is reduced with respect to radiation domination. In this paper, we demonstrate that the specific pattern of this reduction is sensitive…
Inflation predicts a primordial gravitational wave spectrum that is slightly ``red,'' i.e., nearly scale-invariant with slowly increasing power at longer wavelengths. In this paper, we compute both the amplitude and spectral form of the…
We investigate the evolution of cosmological perturbations generated during de Sitter inflation in the conformal gravity. Primordial gravitational waves are composed of vector and tensor modes. We obtain the constant vector and tensor power…