Zobrazeno 1 - 10
of 1 033
pro vyhledávání: '"Sebastiani, L"'
We present an unified approach for the study of idealized gravitational compact objects like wormholes and horizonless stars, here simulated by the presence of boundary conditions at a deeply inner wall. At classical level, namely neglecting quantum
Externí odkaz:
http://arxiv.org/abs/1808.06939
In this paper we investigate how to describe in a unified way a constant-roll inflationary era with a dark energy era, by using the theoretical framework of $F(R)$ gravity. To this end, we introduce some classes of appropriately chosen $F(R)$ gravity
Externí odkaz:
http://arxiv.org/abs/1708.08346
Publikováno v:
Gen.Rel.Grav. 49 (2017) no.7, 90
In this paper, we investigate a class of Horndeski scalar-tensor theory of gravity for warm inflation. We present some models where the early-time acceleration is realized in the weak and in the strong dissipation regime. Cosmological perturbations a
Externí odkaz:
http://arxiv.org/abs/1707.03702
A unified description of early-time inflation with the current cosmic acceleration is achieved by means of a new theory that uses a quadratic model of gravity, with the inclusion of an exponential $F(R)$-gravity contribution for dark energy. High-cur
Externí odkaz:
http://arxiv.org/abs/1706.01879
Publikováno v:
Adv. High Energy Phys. 2017 (2017) 3156915
Mimetic gravity is a Weyl-symmetric extension of General Relativity, related to the latter by a singular disformal transformation, wherein the appearance of a dust-like perfect fluid can mimic cold dark matter at a cosmological level. Within this fra
Externí odkaz:
http://arxiv.org/abs/1612.08661
Publikováno v:
Eur. Phys. J. C75 (2015) 444
We investigate inflation within $f(R,\phi)$-theories, where a dynamical scalar field is coupled to gravity. A class of models which can support early-time acceleration with the emerging of an effective cosmological constant at high curvature is studi
Externí odkaz:
http://arxiv.org/abs/1504.07984
Publikováno v:
Phys. Rev. D 90, 043505 (2014)
We explore conformal-anomaly driven inflation in $F(R)$ gravity without invoking the scalar-tensor representation. We derive the stress-energy tensor of the quantum anomaly in the flat homogeneous and isotropic universe. We investigate a suitable toy
Externí odkaz:
http://arxiv.org/abs/1403.6649
Publikováno v:
Phys. Rev. D 89, 023518 (2014)
We study inflation induced by (power-low) scalar curvature corrections to General Relativity. The class of inflationary scalar potentials $V(\sigma)\sim\exp[n\,\sigma]$, $n$ general parameter, is investigated in the Einsein frame and the correspondin
Externí odkaz:
http://arxiv.org/abs/1311.0744
Publikováno v:
Galaxies, v.1, N2, 83-95 (2013)
We give a brief review of some aspects of inhomogeneous viscous fluids in a flat Friedmann-Robertson-Walker Universe. In general, it is pointed out that several fluid models may bring the future Universe evolution to become singular, with the appeara
Externí odkaz:
http://arxiv.org/abs/1307.4854