Related papers: Gravitational particle production in braneworld co…
In the braneworld scenario ordinary standard model matter and on-gravitational fields are confined by some trapping mechanism to the 4-dimensional universe constituting the D3-branes which are embedded in a (4 + n)-dimensional manifold…
We present a general slow-roll formalism within braneworld-motivated cosmologies with non-standard effective Friedmann equations. Full towers of parameters involving either the inflaton potential or the Hubble parameter are constructed and…
The possibility that around some astrophysical objects there are non-static magnetic fields of enormous intensity suggests that in these situations real particles may be produced. The slowness of the variation is compensated by the huge…
The exactly solvable quantum model of the homogeneous, isotropic and closed universe in the matter-energy production epoch is considered. It is assumed that the universe is originally filled with a uniform scalar field and a perfect fluid…
Through a mechanism similar to perturbative particle scattering, particles of mass $m_\chi$ larger than the Hubble expansion rate $H_\mathrm{inf}$ during inflation can be gravitationally produced at the end of inflation without the…
The scalar and vector cosmological perturbations at all length scales of our Universe are studied in the framework of the phantom braneworld model. The model is characterized by the parameter $\Omega_M\equiv M^3/2m^2H_0$, with $M$ and $m$…
We study the cosmological evolution with nonsingular branes generated by a bulk scalar field coupled to gravity. The specific setup investigated leads to branes with a time-dependent warp factor. We calculate the effective Hubble parameter…
We consider the simplest possibility for a model of particle dark matter in which dark matter has only gravitational interaction with the standard model sector. Even in such a case, it is known that the gravitational particle production in…
The Standard Cosmological Model has experienced tremendous success at reproducing observational data by assuming a universe dominated by a cosmological constant and dark matter in a flat geometry. However, several studies, based on local…
Bursts of weakly interacting particles such as neutrinos or even more weakly interacting particles such as wimps and gravitons from the very early universe would offer a much deeper ``look back time'' to early epochs than is possible with…
Particle production by expanding in the future light cone scalar quantum field is studied by assuming that the initial state is associated with the quasiequilibrium statistical operator corresponding to fluid dynamics. We calculate particle…
Braneworld models with variable brane tension $\lambda $ introduce a new degree of freedom that allows for evolving gravitational and cosmological constants, the latter being a natural candidate for dark energy. We consider a thermodynamic…
Analytic and numerical techniques are presented for computing gravitational production of scalar particles in the limit that the inflaton mass is much larger than the Hubble expansion rate at the end of inflation. These techniques rely upon…
In [26] it had been found that gravitational particle production (to be more specific, gravitational vacuum polarization) results in an effective increase in the directly measured value of the Hubble constant $H_0$ while it does not affect…
We use higher derivative classical gravity to study the nonlinear coupling between the cosmological expansion of the universe and metric oscillations of Planck frequency and very small amplitude. We derive field equations at high orders in…
The braneworld description of our universe entails a large extra dimension and a fundamental scale of gravity that might be lower by several orders of magnitude compared to the Planck scale. An interesting consequence of the braneworld…
Although the cosmological constant has primarily cosmological consequences, its smallness poses one of the basic problems in particle physics. Various attempts have been made to explain this mystery, but no satisfactory solution has been…
We use a method of linearization to study the emergence of the future cosmological singularity characterized by finite value of the cosmological radius. We uncover such singularities that keep Hubble parameter finite while making all higher…
We consider the possibility of a gravitationally induced particle production through the mechanism of a nonminimal curvature-matter coupling. An interesting feature of this gravitational theory is that the divergence of the energy-momentum…
In this paper we work out a multiverse scenario whose physical characteristics enable us to advance the following the conjecture that whereas the physics of particles and fields is confined to live in the realm of the whole multiverse…