scholarly journals Nonlinear Spinor Field in Non-Diagonal Bianchi Type Space-Time

2018 ◽  
Vol 173 ◽  
pp. 02018
Author(s):  
Bijan Saha
Keyword(s):  
Spinor Field ◽  
Bianchi Type ◽  
Space Time ◽  
Coupling Constant ◽  
Nonlinear Spinor ◽  
Bianchi Models ◽  
Rotationally Symmetric ◽  
Big Crunch ◽  
The Universe

Within the scope of the non-diagonal Bianchi cosmological models we have studied the role of the spinor field in the evolution of the Universe. In the non-diagonal Bianchi models the spinor field distribution along the main axis is anisotropic and does not vanish in the absence of the spinor field nonlinearity. Hence within these models perfect fluid, dark energy etc. cannot be simulated by the spinor field nonlinearity. The equation for volume scale V in the case of non-diagonal Bianchi models contains a term with first derivative of V explicitly and does not allow exact solution by quadratures. Like the diagonal models the non-diagonal Bianchi space-time becomes locally rotationally symmetric even in the presence of a spinor field. It was found that depending on the sign of the coupling constant the model allows either an open Universe that rapidly grows up or a close Universe that ends in a Big Crunch singularity.

scholarly journals Spinor field in Bianchi type-IX space–time

2018 ◽  
Vol 96 (10) ◽  
pp. 1074-1084
Author(s):  
Bijan Saha
Keyword(s):  
Spinor Field ◽  
Bianchi Type ◽  
Energy Momentum Tensor ◽  
Early Stage ◽  
Momentum Tensor ◽  
Space Time ◽  
Rapid Expansion ◽  
Coupling Constant ◽  
The One

Within the scope of Bianchi type-IX cosmological model we have studied the role of spinor field in the evolution of the Universe. It is found that unlike the diagonal Bianchi models in this case the components of energy–momentum tensor of spinor field along the principal axis are not the same (i.e., [Formula: see text]), even in the absence of spinor field nonlinearity. The presence of nontrivial non-diagonal components of energy–momentum tensor of the spinor field imposes severe restrictions both on geometry of space–time and on the spinor field itself. As a result the space–time turns out to be either locally rotationally symmetric or isotropic. In this paper we considered the Bianchi type-IX space–time both for a trivial b, that corresponds to standard Bianchi type-IX and the one with a non-trivial b. It was found that a positive self-coupling constant λ1 gives rise to an oscillatory mode of expansion, while a trivial λ1 leads to rapid expansion at the early stage of evolution.

scholarly journals Spinors in Cylindrically Symmetric Space–Time

Universe ◽  
2020 ◽  
Vol 6 (9) ◽  
pp. 152
Author(s):  
Bijan Saha
Keyword(s):  
Gravitational Field ◽  
Symmetric Space ◽  
Spinor Field ◽  
Bianchi Type ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Space Time ◽  
Type I ◽  
Nonlinear Spinor ◽  
Cylindrically Symmetric

We studied the behavior of nonlinear spinor field within the scope of a static cylindrically symmetric space–time. It is found that the energy-momentum tensor (EMT) of the spinor field in this case possesses nontrivial non-diagonal components. The presence of non-diagonal components of the EMT imposes three-way restrictions either on the space–time geometry or on the components of the spinor field or on both. It should be noted that the analogical situation occurs in cosmology when the nonlinear spinor field is exploited as a source of gravitational field given by the Bianchi type-I cosmological model.

scholarly journals MØLLER ENERGY–MOMENTUM PRESCRIPTION FOR A LOCALLY ROTATIONALLY SYMMETRIC SPACE–TIME

2006 ◽  
Vol 21 (18) ◽  
pp. 3845-3853 ◽  
Author(s):  
OKTAY AYDOGDU
Keyword(s):  
General Relativity ◽  
Energy Distribution ◽  
Bianchi Type ◽  
Space Time ◽  
Type Ii ◽  
Theory Of Relativity ◽  
Locally Rotationally Symmetric ◽  
Rotationally Symmetric ◽  
Teleparallel Theory ◽  
The Universe

The energy distribution in the Locally Rotationally Symmetric (LRS) Bianchi type II space–time is obtained by considering the Møller energy–momentum definition in both Einstein's theory of general relativity and teleparallel theory of relativity. The energy distribution which includes both the matter and gravitational field is found to be zero in both of these different gravitation theories. This result agrees with previous works of Cooperstock and Israelit, Rosen, Johri et al., Banerjee and Sen, Vargas, and Aydogdu and Salti. Our result — the total energy of the universe is zero — supports the view points of Albrow and Tryon.

scholarly journals Spinor field with polynomial nonlinearity in LRS Bianchi type-I space–time

2016 ◽  
Vol 94 (1) ◽  
pp. 116-121 ◽  
Author(s):  
Bijan Saha
Keyword(s):  
Spinor Field ◽  
Nonlinear Term ◽  
Bianchi Type ◽  
Mass Term ◽  
Momentum Tensor ◽  
Type I ◽  
Coupling Constant ◽  
Bianchi Type I ◽  
Polynomial Type

Within the scope of the locally rotationally symmetric (LRS) Bianchi type-I cosmological model the role of spinor field on the evolution of the Universe is investigated. In doing so, we have considered a polynomial type of nonlinearity. It is found that, depending on the sign of the self-coupling constant, the model allows either an accelerated mode of expansion or an oscillatory mode of evolution. While the non-diagonal components of the energy–momentum tensor of the spinor field in the case of a full Bianchi type-I model lead to the vanishing mass and nonlinear term in the spinor field Lagrangian, in the case of an LRS Bianchi type-I model neither the mass term nor the nonlinear term of the spinor field vanish.

scholarly journals Mixed fluid cosmological model in f(R, T) gravity

2020 ◽  
Vol 98 (11) ◽  
pp. 1015-1022 ◽  
Author(s):  
Parbati Sahoo ◽  
Barkha Taori ◽  
K.L. Mahanta
Keyword(s):  
Cosmological Model ◽  
Bianchi Type ◽  
Type I ◽  
Time Varying ◽  
Eos Parameter ◽  
Barotropic Fluid ◽  
Rotationally Symmetric ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Mixed Fluid

We construct a locally rotationally symmetric (LRS) Bianchi type-I cosmological model in f(R, T) theory of gravity when the source of gravitation is a mixture of barotropic fluid and dark energy (DE) by employing a time-varying deceleration parameter. We observe through the behavior of the state finder parameters (r, s) that our model begins from the Einstein static era and goes to ΛCDM era. The equation of state (EOS) parameter (ωd) for DE varies from the phantom (ω < –1) phase to quintessence (ω > –1) phase, which is consistent with observational results. It is found that the discussed model can reproduce the current accelerating phase of the expansion of the universe.

scholarly journals ON POSSIBLE GEOMETRIC AND ASTROPHYSICAL EFFECTS OF NONLINEAR SPINOR FIELDS IN THE MEGAMIR, MACROWORLD AND MICROWORLD

Metaphysics ◽  
2020 ◽  
pp. 82-93
Author(s):  
V. G Krechet
Keyword(s):  
General Relativity ◽  
Gravitational Interaction ◽  
Space Time ◽  
Elementary Particles ◽  
Nonlinear Spinor ◽  
Evolution Of The Universe ◽  
Spinor Fields ◽  
Astrophysical Objects ◽  
Local Space ◽  
The Universe

In this article, within the framework of general relativity, the possible effect of the gravitational interaction of Dirac nonlinear spinor fields on the evolution of the Universe, on the formation of astrophysical objects and on the formation of the geometry of the local space-time of elementary particles with spin ħ / 2 is considered.

Interacting self-consistent system of spinor and gravitational fields

2020 ◽  
Vol 35 (02n03) ◽  
pp. 2040047
Author(s):  
Bijan Saha
Keyword(s):  
Spinor Field ◽  
Rapid Expansion ◽  
Minimal Coupling ◽  
Consistent System ◽  
Anisotropic Models ◽  
Gravitational Fields ◽  
Frw Model ◽  
Expansion Of The Universe ◽  
The Universe

Within the scope of simple cosmological models we have studied the role of spinor field in the evolution of the Universe when it is non-minimally coupled to the gravitational one. If the spinor field nonlinearity describes an ordinary matter such as radiation, the presence of non-minimality becomes essential and leads to the rapid expansion of the Universe in FRW model, but this is not the case for LRSBI model. If the spinor field nonlinearity describes a dark energy the role non-minimal coupling becomes insignificant in both isotropic and anisotropic models.

scholarly journals Chaotic inflation in spatially homogeneous Bianchi type V space–time

2017 ◽  
Vol 95 (12) ◽  
pp. 1267-1270
Author(s):  
Raj Bali ◽  
P. Kumari
Keyword(s):  
Bianchi Type ◽  
Space Time ◽  
Late Time ◽  
De Sitter ◽  
Spatially Homogeneous ◽  
Inflationary Parameters ◽  
Type V ◽  
The Universe ◽  
Anisotropic Phase ◽  
Bianchi Type V

Chaotic inflationary scenario in spatially homogeneous Bianchi type V space–time following Linde (Phys. Lett. B, 129, 177 (1983). doi: 10.1016/0370-2693(83)90837-7 ) and the condition [Formula: see text] based on theory of super cooling during the cosmological phase transition proposed by Kirzhnits and Linde (Ann. Phys. 101, 195 (1976). doi: 10.1016/0003-4916(76)90279-7 ), is discussed. It has been found that the model represents anisotropic phase of the Universe in general but at late time, it isotropizes. The deceleration parameter q = −1 indicates that the model leads to de Sitter space–time. It is found that inflationary parameters, namely, slow roll parameters, and anisotropic parameters are in excellent agreement with the Planck Collaboration’s 2013 results (Astron. Astrophys. 571, A22 (2014). doi: 10.1051/0004-6361/201321569 ).

scholarly journals Causal heat flow in Bianchi type-V Universe

2014 ◽  
Vol 29 (13) ◽  
pp. 1450071
Author(s):  
M. Govender ◽  
S. Thirukkanesh
Keyword(s):  
Temperature Profile ◽  
Bianchi Type ◽  
Irreversible Thermodynamics ◽  
Hydrostatic Equilibrium ◽  
Rotationally Symmetric ◽  
Spatially Homogeneous ◽  
Bianchi Type V Universe ◽  
Type V ◽  
Bianchi Type V

In this paper, we investigate the role of causal heat transport in a spatially homogeneous, locally-rotationally symmetric (LRS) Bianchi type-V cosmological model. In particular, the causal temperature profile of the cosmological fluid is obtained within the framework of extended irreversible thermodynamics. We demonstrate that relaxational effects can alter the temperature profile when the cosmological fluid is out of hydrostatic equilibrium.

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