English
Related papers

Related papers: Spin precession in anisotropic cosmologies

200 papers

We examine homogeneous but anisotropic cosmologies in scalar-tensor gravity theories, including Brans-Dicke gravity. We present a method for deriving solutions for any isotropic perfect fluid with a barotropic equation of state…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Jose P. Mimoso , David Wands

We study Bianchi I type brane cosmologies with scalar matter self-interacting through combinations of exponential potentials. Such models correspond in some cases to inflationary universes. We discuss the conditions for accelerated…

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

A spatially homogeneous and anisotropic Bianchi Type I universe has been studied with {\omega} <-1 without Big Smash. It is demonstrated that if cosmic dark energy behaves like a fluid with equation of state p = {\omega}{\rho} (p and {\rho}…

General Relativity and Quantum Cosmology · Physics 2011-08-04 Anil Kumar Yadav

In the framework of parallelism general relativity (PGR), the Dirac particle spin precession in the rotational gravitational field is studied. In terms of the equivalent tetrad of Kerr frame, we investigate the torsion axial-vector spin…

General Relativity and Quantum Cosmology · Physics 2007-05-23 C. M. Zhang

A cosmic no-hair theorem for all initially contracting, spatially homogeneous, orthogonal Bianchi Cosmologies is derived - which shows that all such Universes asymptote to a spatially flat, isotropic Universe with the inclusion of a shear…

General Relativity and Quantum Cosmology · Physics 2021-07-21 Chandrima Ganguly

In this paper, we present a model of transitioning universe with minimal interaction between perfect fluid and anisotropic dark energy in Bianchi I space-time. The two sources are assumed to minimally interacted and therefore their energy…

General Relativity and Quantum Cosmology · Physics 2016-08-19 Anil Kumar Yadav

The topology of the universe is discussed in relation to the singularity problem. We explore the possibility that the initial state of the universe might have had a structure with 3-Klein bottle topology, which would lead to a model of a…

General Physics · Physics 2009-01-23 V. N. Yershov

Spatiotemporal spin dynamics under spin-orbit interaction is investigated in a (001) GaAs two-dimensional electron gas using magneto-optical Kerr rotation microscopy. Spin polarized electrons are diffused away from the excited position,…

Mesoscale and Nanoscale Physics · Physics 2021-01-20 Daisuke Iizasa , Asuka Aoki , Takahito Saito , Junsaku Nitta , Gian Salis , Makoto Kohda

Spin (spherical) random fields are very important in many physical applications, in particular they play a key role in Cosmology, especially in connection with the analysis of the Cosmic Microwave Background radiation. These objects can be…

Probability · Mathematics 2022-07-19 Antonio Lerario , Domenico Marinucci , Maurizia Rossi , Michele Stecconi

A generally anisotropic equation of state originally derived in the context of Newman-Janis rotating systems allows for vacuum energy at a specific density. In this paper we examine the possibility of using that equation of state for…

General Relativity and Quantum Cosmology · Physics 2023-09-08 Philip Beltracchi

Different characteristic of matter influencing the evolution of the Universe has been simulated by means of a nonlinear spinor field. Exploiting the spinor description of perfect fluid and dark energy evolution of the Universe given by an…

General Relativity and Quantum Cosmology · Physics 2015-05-01 Bijan Saha

A self-consistent system of nonlinear spinor and Bianchi type-V anisotropic gravitational fields are investigated. It is found that the presence of nontrivial non-diagonal components of the energy-momentum tensor of the spinor field imposes…

General Relativity and Quantum Cosmology · Physics 2016-02-19 Bijan Saha

In the framework of spacetime with torsion and without curvature, the Dirac particle spin precession in the rotational system is studied. We write out the equivalent tetrad of rotating frame, in the polar coordinate system, through…

General Relativity and Quantum Cosmology · Physics 2015-06-25 C. M. Zhang

We provide a quantum picture for the emergence of a bouncing cosmology, according to the idea that a semiclassical behavior of the Universe towards the singularity is not available in many relevant Minisuperspace models. In particular, we…

General Relativity and Quantum Cosmology · Physics 2022-09-07 Eleonora Giovannetti , Giovanni Montani

We explore locally rotationally symmetric Bianchi I universe in Brans-Dicke gravity with self-interacting potential by using charged viscous cosmological string fluid. We use a relationship between the shear and expansion scalars and also…

General Relativity and Quantum Cosmology · Physics 2015-06-05 M. Sharif , Saira Waheed

A self-consistent system of interacting spinor and scalar fields is considered within the scope of Bianchi type VI cosmological model filled with a perfect fluid. The contribution of the cosmological constant ($\Lambda$-term) is taken into…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Bijan Saha

We discuss the problem of the stability of the isotropy of the universe in the space of ever-expanding spatially homogeneous universes with a compact spatial topology. The anisotropic modes which prevent isotropy being asymptotically stable…

General Relativity and Quantum Cosmology · Physics 2008-11-26 John D. Barrow , Hideo Kodama

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

An anisotropic (Bianchi type I) cosmology is considered in the four-dimensional NS-NS sector of low-energy effective string theory coupled to a dilaton and an axion-like $H$-field within a de Sitter-Einstein frame background. The time…

High Energy Physics - Theory · Physics 2009-10-31 Chiang-Mei Chen , T. Harko , M. K. Mak

In this paper we have investigated the general form of viscous and non-viscous dark energy equation of state (EoS) parameter in the scope of anisotropic Bianchi type I space-time. We show that the presence of bulk viscosity causes…

General Relativity and Quantum Cosmology · Physics 2014-03-20 Hassan Amirhashchi , Anirudh Pradhan