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As opposed to Wald's cosmic no-hair theorem in general relativity, it is shown that the Horndeski theory (and its generalization) admits anisotropic inflationary attractors if the Lagrangian depends cubically on the second derivatives of…

General Relativity and Quantum Cosmology · Physics 2018-08-01 Hiroaki W. H. Tahara , Sakine Nishi , Tsutomu Kobayashi , Jun'ichi Yokoyama

After a more general assumption on the influence of the bulk on the brane, we extend some conclusions by Maartens et al. and Santos et al. on the asymptotic behavior of Bianchi I brane worlds. As a consequence of the nonlocal anisotropic…

General Relativity and Quantum Cosmology · Physics 2009-11-10 J. M. Aguirregabiria , L. P. Chimento , Ruth Lazkoz

The influence of Inflation on initial (i.e. at Planck's epoch) large anisotropy of the Universe is studied, considering a more general metric than the isotropic one: the locally rotationally symmetric (L.R.S.) Bianchi IX metric. We find,…

General Relativity and Quantum Cosmology · Physics 2014-11-17 R. Bergamini , P. Sedici , P. Verrocchio

Anisotropic inflation is a model succeeded in explaining statistical anisotropy. Warm inflation is a model succeeded in providing a mechanism of reheating during inflation. We study anisotropic warm inflation focusing on the cosmic no-hair…

High Energy Physics - Theory · Physics 2023-06-09 Sugumi Kanno , Ann Mukuno , Jiro Soda , Kazushige Ueda

In this paper, we investigate anisotropic cosmological solutions within the framework of Born-Infeld-f(R) gravity, a modification of general relativity that incorporates higher-order curvature invariants. Specifically, we focus on the…

General Relativity and Quantum Cosmology · Physics 2025-01-06 Salih Kibaroğlu

The behaviour of a non-canonical scalar field within an anisotropic Bianchi type I, spatially homogeneous, Universe in the framework of the intermediate inflation will be studied. It will be examined on the condition that both the…

General Physics · Physics 2019-08-19 Mahdeyeh Naderi , Ali Aghamohammadi , Abdollah Refaei , Haidar Sheikhahmadi

Non-singular Bianchi type I solutions are found from the effective action with a superstring-motivated Gauss-Bonnet term. These anisotropic non-singular solutions evolve from the asymptotic Minkowski region, subsequently super-inflate, and…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Shinsuke Kawai , Jiro Soda

The presence of a nonconformally invariant term in the photon sector of the Lorentz-violating extension of Standard Model of particle physics, the "Kosteleck\'{y} term" $\mathcal{L}_K \propto (k_F)_{\alpha \beta \mu \nu} F^{\alpha \beta}…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-06 Leonardo Campanelli

Gauge-flation, inflation from non-Abelian gauge fields, was introduced in [1,2]. In this work, we study the cosmic no-hair conjecture in gauge-flation. Starting from Bianchi-type I cosmology and through analytic and numeric studies we…

High Energy Physics - Theory · Physics 2015-05-30 A. Maleknejad , M. M. Sheikh-Jabbari , Jiro Soda

We study the cosmology in the presence of arbitrary couplings between $p$-forms in 4-dimensional space-time for a general action respecting gauge symmetry and parity invariance. The interaction between 0-form (scalar field $\phi$) and…

General Relativity and Quantum Cosmology · Physics 2019-03-15 Juan P. Beltrán Almeida , Alejandro Guarnizo , Ryotaro Kase , Shinji Tsujikawa , César A. Valenzuela-Toledo

Anisotropic inflation is an interesting model with an U(1) gauge field and it predicts the statistical anisotropy of the curvature perturbation characterized by a parameter $g_*$. However, we find that the background gauge field does not…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-14 Tomohiro Fujita , Ippei Obata

We use one of the simplest forms of the K-essence theory and we apply it to the classical anisotropic Bianchi type I cosmological model, with a barotropic perfect fluid modeling the usual matter content and with cosmological constant. The…

General Relativity and Quantum Cosmology · Physics 2014-09-11 J. Socorro , Luis O. Pimentel , Abraham Espinoza-García

We present the classical solutions to the Einstein field equations derived using the WKB-like and Hamilton procedures. The investigation is carried out in the commutative and noncommutative scenario for the Bianchi type I cosmological model…

General Relativity and Quantum Cosmology · Physics 2009-11-13 C. Ortiz , E. Mena-Barboza , M. Sabido , J. Socorro

We consider Brans Dicke scalar vector tensor gravity to study an inflationary scenario of the accelerating expansion of the universe for which the anisotropy property occurs. We study both primordial inflation and late inflationary period…

General Relativity and Quantum Cosmology · Physics 2022-09-20 Hossein Ghaffarnejad , Hoda Gholipour

We consider the non-minimal model of gravity in $Y(R) F^2$-form. We investigate a particular case of the model, for which the higher order derivatives are eliminated but the scalar curvature $R$ is kept to be dynamical via the constraint…

General Relativity and Quantum Cosmology · Physics 2017-11-17 Muzaffer Adak , Ozgur Akarsu , Tekin Dereli , Ozcan Sert

In the scope of the nonlinear massive gravity, we study fixed points of evolution equations for a Bianchi type--I universe. We find a new attractor solution with non-vanishing anisotropy, on which the physical metric is isotropic but the…

High Energy Physics - Theory · Physics 2012-10-17 A. Emir Gumrukcuoglu , Chunshan Lin , Shinji Mukohyama

We investigate the cosmological reconstruction in anisotropic universe for both homogeneous and inhomogeneous content of the universe. Special attention is attached to three interesting cases: Bianchi type-I, Bianchi type-III and…

General Relativity and Quantum Cosmology · Physics 2012-11-29 M. E. Rodrigues , M. J. S. Houndjo , D. Saez-Gomez , F. Rahaman

The topic of this talk is a new inflationary model in the context of Type IIB string compactifications called Loop Blow-Up Inflation, presented in arXiv:2403.04831. The original Blow-Up Inflation model, whose potential was purely…

High Energy Physics - Theory · Physics 2025-02-24 Luca Brunelli

The presence of a light vector field coupled to a scalar field during inflation makes a distinct prediction: the observed correlation functions of the cosmic microwave background (CMB) become statistically anisotropic. We study the…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-24 Atsushi Naruko , Eiichiro Komatsu , Masahide Yamaguchi

Inflationary models within string theory exhibit unusual scalar field dynamics involving non-minimal kinetic terms and generically referred to as k-inflation. In this situation, the standard slow-roll approach used to determine the behavior…

Cosmology and Nongalactic Astrophysics · Physics 2012-05-08 Christophe Ringeval