相关论文: Enhancement of second-order gravitational waves at…
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…
Supersymmetry predicts multiple flat directions, some of which carry a net baryon or lepton number. Condensates in such directions form during inflation and later fragment into Q-balls, which can become the building blocks of primordial…
Particle decays are always accompanied by the emission of graviton quanta of gravity through bremsstrahlung processes. However, the corresponding branching ratio is suppressed by the square of the ratio of particle's mass to the Planck…
We investigate density fluctuations and scalar-induced gravitational waves (GWs) arising from the production of long-lived solitons and oscillons, which can dominate the early Universe and drive reheating prior to the standard…
We propose a novel mechanism where a first-order phase transition modulates the decay rate of a massive field. This modulation, even if the scalar field has negligible energy density, subsequently generates an observable stochastic…
Curvature perturbations induce gravitational waves (GWs) at second order, contributing to the stochastic gravitational wave background. The resulting gravitational wave spectrum is sensitive to the evolutionary history of the universe and…
We study the detectability of the gravitational waves (GWs) from the Q-ball formation associated with the Affleck-Dine (AD) mechanism, taking into account both of the dilution effect due to Q-ball domination and of finite temperature…
In the pre-reheating era, following cosmic inflation and preceding radiation domination, the energy density may be dominated by an oscillating massive scalar condensate, such as is the case for quadratic chaotic inflation. We have found in…
Gravitational waves are propagating undulations in the spacetime fabric, which interact very weakly with their environment. In cosmology, gravitational-wave distortions are produced by most of the inflationary scenarios and their…
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…
On the frequency-amplitude plane, Gravitational Waves (GWs) from cosmic strings show a flat plateau at higher frequencies due to the string loop dynamics in standard radiation dominated post-inflationary epoch. The spectrum may show an…
We study the gravitational wave phenomenology in models of solitosynthesis. In such models, a first order phase transition is precipitated by a period in which non-topological solitons with a conserved global charge (Q-balls) accumulate…
In Affleck-Dine baryogenesis, the observed baryon asymmetry of the Universe is generated through the evolution of the vacuum expectation value (VEV) of a scalar condensate. This scalar condensate generically fragments into non-topological…
We study the impact of non-thermal leptogenesis on the spectrum of gravitational waves (GWs) produced by a strong first-order phase transition in the early Universe. We consider a scenario in which a heavy scalar field, $\phi$, dominates…
This thesis focuses on gravitational waves (GWs) that arise beyond linear order in cosmological perturbation theory. In recent years, scalar-induced GWs have attracted significant attention because they may serve as the observational…
In a previous paper [1] we considered the possibility that (within the early-radiation epoch) there has been (also) a short period of a significant presence of cosmic strings. During this radiation-plus-strings stage the Universe…
A generic consequence of supersymmetry is formation of a scalar condensate along the flat directions of the potential at the end of cosmological inflation. This condensate is usually unstable, and it can fragment into non-topological…
We investigate the Q-ball decay in the gauge-mediated SUSY breaking. Q balls decay mainly into nucleons, and partially into gravitinos, while they are kinematically forbidden to decay into sparticles which would be cosmologically harmful.…
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,…
The imprint of gravitational waves (GWs) on large-scale structures (LSS) is a useful and promising way to detect or to constrain them. Tensor fossils have been largely studied in the literature as an indirect way to detect primordial GWs.…