Périgois, Carole Santoliquido, Filippo Bouffanais, Yann Di Carlo, Ugo N. Giacobbo, Nicola Rastello, Sara Mapelli, Michela Regimbau, Tania

We study the impact of young clusters on the gravitational wave background from compact binary coalescence. We simulate a catalog of sources from population I/II isolated binary stars and stars born in young clusters, corresponding to one year of observations with second-generation (2G) detectors. Taking into account uncertainties on the fraction o...

He, Yutong Pol, Alberto Roper Brandenburg, Axel

We study the leading-order nonlinear gravitational waves (GWs) produced by an electromagnetic (EM) stress in reheating magnetogenesis scenarios. Both nonhelical and helical magnetic fields are considered. By numerically solving the linear and leading-order nonlinear GW equations, we find that the GW energy from the latter is usually larger. We comp...

Tail, Saad

We investigate the vacuum properties of a massless scalar field theory in constrained spatial geometry, namely, the instantaneous appearance of a thick Dirichlet boundary inside a one-dimensional (1D) Dirichlet cavity and divides it into two parts. Our work presents the calculations for the energy density and particle number density created. The ex...

Musco, Ilia Papanikolaou, Theodoros

This work investigates the formation of primordial black holes within a radiation fluid with an anisotropic pressure. We focus our attention on the initial conditions describing cosmological perturbations on the super horizon regime, using a covariant form of the equation of state in terms of pressure and energy density gradients. The effect of the...

Garcia, Marcos A.G. Kaneta, Kunio Mambrini, Yann Olive, Keith A. Verner, Sarunas

We consider the production of dark matter during the process of reheating after inflation. The relic density of dark matter from freeze-in depends on both the energy density and energy distribution of the inflaton scattering or decay products composing the radiation bath. We compare the perturbative and non-perturbative calculations of the energy d...

Boileau, Guillaume Christensen, Nelson Meyer, Renate Cornish, Neil J.

With the goal of attempting to observe a stochastic gravitational wave background (SGWB) with LISA, the spectral separability of the cosmological and astrophysical backgrounds is important to estimate. We attempt to determine the level with which a cosmological background can be observed given the predicted astrophysical background level. We predic...

Wu, Yi-Peng Pinetti, Elena Silk, Joseph

If primordial black holes (PBHs) contribute more than 10 percent of the dark matter (DM) density, their energy density today is of the same order as that of the baryons. Such a cosmic coincidence might hint at a mutual origin for the formation scenario of PBHs and the baryon asymmetry of the Universe. Baryogenesis can be triggered by a sharp transi...

Hill, J. Colin Calabrese, Erminia Aiola, Simone Battaglia, Nicholas Bolliet, Boris Choi, Steve K. Devlin, Mark J. Duivenvoorden, Adriaan J. Dunkley, Jo Ferraro, Simone
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The early dark energy (EDE) scenario aims to increase the value of the Hubble constant ($H_0$) inferred from cosmic microwave background (CMB) data over that found in $\Lambda$CDM, via the introduction of a new form of energy density in the early universe. The EDE component briefly accelerates cosmic expansion just prior to recombination, which red...

Fumagalli, Jacopo Renaux-Petel, Sébastien Witkowski, Lukas T.

We identify a characteristic pattern in the scalar-induced stochastic gravitational wave background from particle production during inflation. If particle production is sufficiently efficient, the scalar power spectrum exhibits $\mathcal{O}(1)$ oscillations periodic in $k$, characteristic of a sharp feature, with an exponentially enhanced envelope....

Chavanis, Pierre-Henri

We determine the k-essence Lagrangian of a relativistic barotropic fluid. The equation of state of the fluid can be specified in different manners depending on whether the pressure is expressed in terms of the energy density (model I), the rest-mass density (model II), or the pseudo rest-mass density for a complex scalar field in the Thomas-Fermi a...