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Homogeneous isotropic spatial flat cosmological models with two torsion functions in vacuum are built and investigated in the framework of de Sitter gauge theory of gravity. It is shown that by certain choices of parameters of gravitational…

广义相对论与量子宇宙学 · 物理学 2011-10-18 Guo-Ying Qi

The dynamical consequences of a bimetric scalar-tensor theory of gravity with a dynamical light speed are investigated in a cosmological setting. The model consists of a minimally-coupled self-gravitating scalar field coupled to ordinary…

广义相对论与量子宇宙学 · 物理学 2009-11-07 M. A. Clayton , J. W. Moffat

The vacuum expectation value of the energy-momentum tensor and the Casimir forces are investigated for a massive scalar field with an arbitrary curvature coupling parameter in the geometry of two parallel plates, on the background of de…

高能物理 - 理论 · 物理学 2011-12-01 A. A. Saharian

We consider late-time cosmology in a (phantom) scalar-tensor theory with an exponential potential, as a dark energy model with equation of state parameter close to -1 (a bit above or below this value). Scalar (and also other kinds of)…

高能物理 - 理论 · 物理学 2009-09-17 Emilio Elizalde , Shin'ichi Nojiri , Sergei D. Odintsov

A dynamical resolution to the cosmological constant fine-tuning problem has been previously put forward, based on a scalar-tensor gravitational theory possessing de Sitter attractor solutions characterized by a small Hubble expansion rate,…

广义相对论与量子宇宙学 · 物理学 2021-08-19 Oleg Evnin , Victor Massart , Kevin Nguyen

A large class of the dynamical laws for causal sets described by a classical process of sequential growth yield a cyclic universe, whose cycles of expansion and contraction are punctuated by single `origin elements' of the causal set. We…

广义相对论与量子宇宙学 · 物理学 2010-05-12 Maqbool Ahmed , David Rideout

We study strongly coupled mass-deformed-CFT on a fixed de Sitter spacetime in three dimensions via holography. We elucidate the global causal structure of the four-dimensional spacetime dual to the de Sitter invariant vacuum state. The…

高能物理 - 理论 · 物理学 2022-06-02 José Manuel Penín , Kostas Skenderis , Benjamin Withers

There are several studies proposing phenomenological consequences of a deformation of special and general relativity. Here, we cast novel constraints on the deformation parameter of a metric in the cotangent bundle accounting for a curved…

广义相对论与量子宇宙学 · 物理学 2020-11-18 J. J. Relancio , S. Liberati

We construct a piecewise model that gives a physical viable realization of finite-time future singularity for a spatially flat Friedmann-Robertson-Walker universe within the interacting dark matter--dark energy framework, with the latter…

广义相对论与量子宇宙学 · 物理学 2017-03-14 Mauricio Cataldo , Luis P. Chimento , Martín G. Richarte

In many different ways, Deformed Special Relativity (DSR) has been argued to provide an effective limit of quantum gravity in almost-flat regime. Unfortunately DSR is up to now plagued by many conceptual problems (in particular how it…

广义相对论与量子宇宙学 · 物理学 2015-06-25 Florian Girelli , Etera R. Livine

The concept of deformation of Riemannian geometry is reviewed, with applications to gravitation and cosmology. Starting with an analysis of the cosmological constant problem, it is shown that space-times are deformable in the sense of local…

广义相对论与量子宇宙学 · 物理学 2015-05-28 M. D. Maia

We obtain conditions for the existence and stability of de Sitter attractors in the phase space of spatially homogeneous and isotropic cosmology in generalized theories of gravity (including non-linear and scalar-tensor theories). These…

广义相对论与量子宇宙学 · 物理学 2009-11-10 Valerio Faraoni

In the presence of a cosmological constant, ordinary Poincare' special relativity is no longer valid and must be replaced by a de Sitter special relativity, in which Minkowski space is replaced by a de Sitter spacetime. In consequence, the…

广义相对论与量子宇宙学 · 物理学 2009-11-13 R. Aldrovandi , J. P. Beltran Almeida , J. G. Pereira

A formalism for the appearance of dark energy in the matter dominated era, leading to a persistent de Sitter expansion at the late time is proposed. Our framework is a hybrid quintessence model with a non-minimal coupling to the Ricci…

广义相对论与量子宇宙学 · 物理学 2018-11-29 H. Mohseni Sadjadi

We consider the supersymmetry breaking effects on typical inflation models with different types of K\"ahler potential. The critical size of supersymmetry-breaking scale, above which the flatness of the inflaton potential is spoiled,…

高能物理 - 理论 · 物理学 2015-06-22 Hiroyuki Abe , Shuntaro Aoki , Fuminori Hasegawa , Yusuke Yamada

Scalar-tensor theories have taken on a key role in attempts to confront the growing open questions in standard cosmology. It is important to understand entirely their dynamics at perturbative level including any possible spatial dependence…

广义相对论与量子宇宙学 · 物理学 2024-12-04 Maria Caruana , Gabriel Farrugia , Jackson Levi Said , Joseph Sultana

We consider a higher dimensional gravity theory with a negative kinetic energy scalar field and a cosmological constant. We find that the theory admits an exact cosmological solution for the scale factor of our universe. It has the feature…

广义相对论与量子宇宙学 · 物理学 2008-11-26 S. T. Hong , J. Lee , T. H. Lee , P. OH

Generic cosmological models derived from higher dimensional theories with warped extra dimensions have a nonzero cosmological constant-like term induced on the 3+1 space-time, or a physical 3-brane. In the scenario where this 3+1 space-time…

广义相对论与量子宇宙学 · 物理学 2011-01-13 Ishwaree P Neupane

A particular framework for quantum gravity is the doubly special relativity (DSR) formalism that introduces a new observer independent scale (the Planck scale). We resort to the methods of statistical mechanics in this framework to…

高能物理 - 理论 · 物理学 2017-07-17 Mir Mehedi Faruk , Md. Muktadir Rahman

We investigate the formation of the large scale structures in the present accelerated era in $f(R)$ gravity background. This is done by considering the linear growth of matter perturbations at low redshift $z<1$. The effect of $f(R)$ alters…

宇宙学与河外天体物理 · 物理学 2022-03-15 Ajay Kumar Sharma , Murli Manohar Verma