Zobrazeno 1 - 10
of 1 031
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
Publikováno v:
Classical and Quantum Gravity, v. 30, N23, 235013 (2013)
Much attention has been recently devoted to modified theories of gravity in the attempt to efficiently describe both early inflation and late-time acceleration of our universe without referring to the cosmological constant or other ad hoc kinds of fl
Externí odkaz:
http://arxiv.org/abs/1306.4750