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Warm inflation in the framework of locally rotationally symmetric Bianchi type I universe model in the Hamilton-Jacobi formalism is being considered. Matter-Radiation fluid in warm inflation, endowed with and without a viscous pressure. For…

General Relativity and Quantum Cosmology · Physics 2023-10-25 M Tirandari , A Mohammadi

A set of power-law solutions of a conformal-violating Maxwell model with a non-standard scalar-vector coupling will be shown in this paper. In particular, we are interested in a coupling term of the form $X^{2n} F^{\mu\nu}F_{\mu\nu}$ with…

General Relativity and Quantum Cosmology · Physics 2018-05-23 Tuan Q. Do , W. F. Kao

The stability of isotropic cosmological solutions in the Bianchi I model is considered. We prove that the stability of isotropic solutions in the Bianchi I metric for a positive Hubble parameter follows from their stability in the…

High Energy Physics - Theory · Physics 2009-11-05 Irina Ya. Aref'eva , Nikolay V. Bulatov , Liudmila V. Joukovskaya , Sergey Yu. Vernov

We seek power-law Bianchi type I solutions for an inflationary universe in a model with one scalar field non-minimally coupled to three vector fields aligned along the three axes. As a result, we find four types of power-law solutions that…

General Relativity and Quantum Cosmology · Physics 2025-11-20 Duy H. Nguyen , Tuan Q. Do

In this article, we examine the effects of anisotropy on a model of canonical warm inflation with the power-law potential. The results of this model are compared to Planck satellite observational data. Using a conventional local scalar…

General Relativity and Quantum Cosmology · Physics 2022-05-05 Zahra Ghadiri , Ali Aghamohammadi , Abdollah Refaei

Recent observations of large-scale statistical isotropy violations have prompted the adoption of anisotropic cosmological models that account for inherent directional curvature. Studies of these anisotropic spacetimes have shown how they…

General Relativity and Quantum Cosmology · Physics 2026-05-22 Devika J. S. , Tanay Gupta , Sukanta Panda

Anisotropic and isotropic slow-roll inflation supported by n-forms are sought. Canonical field strengths and their duals are taken into account, and they are allowed to have a potential and also, when necessary for slow-roll, a nonminimal…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-24 Tomi S. Koivisto , David F. Mota , Cyril Pitrou

We consider an inflationary scenario where the rate of inflaton roll defined by $\ddot\phi/H\dot \phi$ remains constant. The rate of roll is small for slow-roll inflation, while a generic rate of roll leads to the interesting case of…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-09 Hayato Motohashi , Alexei A. Starobinsky , Jun'ichi Yokoyama

We study an inflationary scenario with a vector field coupled with an inflaton field and show that the inflationary universe is endowed with anisotropy for a wide range of coupling functions. This anisotropic inflation is a tracking…

High Energy Physics - Theory · Physics 2009-06-30 Masa-aki Watanabe , Sugumi Kanno , Jiro Soda

The solutions to the Einstein-Klein-Gordon equations without a cosmological constant are investigated for an exponential potential in a Bianchi VI_0 metric. There exists a two-parameter family of solutions which have a power-law…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Luis P. Chimento , Pablo Labraga

We provide an explicit solution representing an anisotropic power law inflation within the framework of rolling tachyon model. This is generated by allowing a non-minimal coupling between the tachyon and the world-volume gauge field on…

High Energy Physics - Theory · Physics 2012-01-25 Samrat Bhowmick , Sudipta Mukherji

We use exact general solutions for the spatially flat FRW and the anisotropic Bianchi I cosmologies to show that generically uncoupled scalar fields cooperate to make inflation more probable, while the presence of several interacting fields…

General Relativity and Quantum Cosmology · Physics 2016-08-15 J. M. Aguirregabiria , A. Chamorro , L. P. Chimento , N. A. Zuccalá

We consider several new classes of viable vector field alternatives to the inflaton and quintessence scalar fields. Spatial vector fields are shown to be compatible with the cosmological anisotropy bounds if only slightly displaced from the…

Astrophysics · Physics 2010-11-19 Tomi S. Koivisto , David F. Mota

We derive a special scalar field potential using the anisotropic Bianchi type I cosmological model from canonical quantum cosmology under determined conditions in the evolution to anisotropic variables $\beta_\pm$. In the process, we obtain…

General Relativity and Quantum Cosmology · Physics 2014-11-21 J. Socorro , Marco D'Oleire

This paper explores the dynamics of warm intermediate and logamediate inflationary models during weak dissipative regime with a general form of dissipative coefficient. We analyze these models within the framework of locally rotationally…

General Relativity and Quantum Cosmology · Physics 2016-03-23 M. Sharif , Rabia Saleem

In this work, we study constant-roll inflation driven by a scalar field with non-minimal derivative coupling to gravity, via the Einstein tensor. This model contains a free parameter, $\eta$, which quantifies the non-minimal derivative…

General Relativity and Quantum Cosmology · Physics 2019-10-23 A. Oliveros , Hernán E. Noriega

In this article, we propose an anisotropic Bianchi-I type cosmological model in non-conservative Unimodular Gravity ($\mathrm{NUG}$). We show that simply using the Bianchi-I type metric does not resolve a striking characteristic of the…

General Relativity and Quantum Cosmology · Physics 2025-11-26 Marcelo H. Alvarenga , Júlio C. Fabris

We study curvature perturbations in the anisotropic inflationary model with a complex scalar field charged under a $U(1)$ gauge field in Bianchi I universe. Due to Abelian Higgs mechanism, the gauge field receives an additional longitudinal…

High Energy Physics - Theory · Physics 2015-06-12 Razieh Emami , Hassan Firouzjahi

It is well known that the viscous Bianchi type-I metric of the Kasner form is not able to describe an anisotropic universe, which satisfies the second law of thermodynamics and the dominant energy condition in Einstein's theory of gravity.…

General Relativity and Quantum Cosmology · Physics 2008-11-12 Seokcheon Lee

We study anisotropic inflation with Gauss-Bonnet correction in presence of a massless vector field. In this scenario, exact anisotropic power-law inflation is realized when the inflaton potential, gauge coupling function and the…

High Energy Physics - Theory · Physics 2016-10-06 Sayantani Lahiri