Sunil Kumar Tripathy | Indira Gandhi Institute of Technology,Sarang (original) (raw)
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Papers by Sunil Kumar Tripathy
The European Physical Journal C
In this paper, we have emphasized the stability analysis of the accelerating cosmological models ... more In this paper, we have emphasized the stability analysis of the accelerating cosmological models obtained in f(T) gravity theory. The behaviour of the models based on the evolution of the equation of state parameter shows phantom-like behaviour at the present epoch. The scalar perturbation technique is used to create the perturbed evolution equations, and the stability of the models has been demonstrated. Also, we have performed the dynamical system analysis for both the models. In the two specific f(T) gravity models, three critical points are obtained in each model. In each model, at least one critical point has been observed to be stable.
Anisotropic Bianchi-III cosmological model is investigated with variable gravitational and cosmol... more Anisotropic Bianchi-III cosmological model is investigated with variable gravitational and cosmological constants in the framework of Einstein's general relativity. The shear scalar is considered to be proportional to the expansion scalar. The dynamics of the anisotropic universe with variable G and Lambda are discussed. Without assuming any specific forms for Lambda and the metric potentials, we have tried to extract the time variation of G and Lambda from the anisotropic model. The extracted G and Lambda are in conformity with the present day observation. Basing upon the observational limits, the behaviour and range of the effective equation of state parameter are discussed.
μ + + + e p n matter (NSM) at finite temperature T is crucial in the study of formation mechanism... more μ + + + e p n matter (NSM) at finite temperature T is crucial in the study of formation mechanism of neutron stars (NS) which have temperature as high as ~50 MeV in the core at when they born. In the present work, our objective is to calculate the NS properties at finite T with particular emphasis on the momentum dependence of nucleonic mean fields. We have used the Yukawa effective interaction (YEI) in our study that has been successfully used in the calculations of EOS of NSM at finite temperature [1] and thermal evolution of properties of nuclear matter (NM) [2]. The temperature dependence of the mean fields and the interaction parts of the energy densities are simulated through the Fermi-Dirac momentum distribution functions while the interaction itself is temperature independent. Hence, in order to have the correct thermal evolution it is necessary to know the correct momentum dependence of the nucleonic mean fields. But this aspect of the nucleonic mean field has remained as a...
Physics of the Dark Universe, 2021
Fortschritte der Physik, 2021
International Journal of Geometric Methods in Modern Physics, 2020
A bouncing scenario is studied in the framework of generalized Brans–Dicke theory. In order to ha... more A bouncing scenario is studied in the framework of generalized Brans–Dicke theory. In order to have a dark energy (DE) driven late time cosmic acceleration, we have considered a unified dark fluid simulated by a linear equation of state (EoS). The evolutionary behavior of the DE equation of parameter derived from the unified dark fluid has been discussed. The effect of the bouncing scale factor on the Brans–Dicke parameter, self-interacting potential and the Brans–Dicke scalar field is investigated.
The European Physical Journal Plus, 2019
Astrophysics and Space Science, 2018
The European Physical Journal Plus, 2016
Communications in Physics, 2010
The European Physical Journal Plus, 2017
Advances in High Energy Physics, 2016
The energy and momentum of some diagonal anisotropic Bianchi type Universes are obtained using di... more The energy and momentum of some diagonal anisotropic Bianchi type Universes are obtained using different energy-momentum complexes in the framework of General Relativity. The Møller energy is found to be zero for all the Universes considered in the present work. In all other prescriptions, the energy and momentum vanish when the sum of the metric parametersαandβvanishes. This result obviously raises a question: why this specific choice? We have explored Tryon’s conjecture that the Universe must have a zero net value for all conserved quantities to get some ideas on this issue.
Plane symmetric bulk viscous string cosmological models with strange quark matter are investigate... more Plane symmetric bulk viscous string cosmological models with strange quark matter are investigated. We have incorporated bulk viscous pressure to study its affect on the properties of the model. Assuming an anisotropic relationship among the metric potentials, we have tried to put some constraints on the anisotropic parameter.
The European Physical Journal C, 2015
Journal of Physics G: Nuclear and Particle Physics, 2011
International Journal of Theoretical Physics, 2013
Anisotropic Locally Rotationally Symmetric Bianchi-I (LRSBI) cosmological model is investigated w... more Anisotropic Locally Rotationally Symmetric Bianchi-I (LRSBI) cosmological model is investigated with variable gravitational and cosmological constants in the framework of Einstein’s general relativity. The shear scalar is considered to be proportional to the expansion scalar. The dynamics of the anisotropic universe with variable G and Λ are discussed. Our calculations for the Supernova constraints concerning the luminosity distance provide reasonable results.
International Journal of Theoretical Physics, 2010
Page 1. Int J Theor Phys (2010) 49: 25692581 DOI 10.1007/s10773-010-0448-5 Bulk Viscous Bianchi-... more Page 1. Int J Theor Phys (2010) 49: 25692581 DOI 10.1007/s10773-010-0448-5 Bulk Viscous Bianchi-III Models with Time Dependent G and Dipanjali Behera · Sunil K. Tripathy · Tushar R. Routray Received: 23 May 2010 ...
The European Physical Journal C
In this paper, we have emphasized the stability analysis of the accelerating cosmological models ... more In this paper, we have emphasized the stability analysis of the accelerating cosmological models obtained in f(T) gravity theory. The behaviour of the models based on the evolution of the equation of state parameter shows phantom-like behaviour at the present epoch. The scalar perturbation technique is used to create the perturbed evolution equations, and the stability of the models has been demonstrated. Also, we have performed the dynamical system analysis for both the models. In the two specific f(T) gravity models, three critical points are obtained in each model. In each model, at least one critical point has been observed to be stable.
Anisotropic Bianchi-III cosmological model is investigated with variable gravitational and cosmol... more Anisotropic Bianchi-III cosmological model is investigated with variable gravitational and cosmological constants in the framework of Einstein's general relativity. The shear scalar is considered to be proportional to the expansion scalar. The dynamics of the anisotropic universe with variable G and Lambda are discussed. Without assuming any specific forms for Lambda and the metric potentials, we have tried to extract the time variation of G and Lambda from the anisotropic model. The extracted G and Lambda are in conformity with the present day observation. Basing upon the observational limits, the behaviour and range of the effective equation of state parameter are discussed.
μ + + + e p n matter (NSM) at finite temperature T is crucial in the study of formation mechanism... more μ + + + e p n matter (NSM) at finite temperature T is crucial in the study of formation mechanism of neutron stars (NS) which have temperature as high as ~50 MeV in the core at when they born. In the present work, our objective is to calculate the NS properties at finite T with particular emphasis on the momentum dependence of nucleonic mean fields. We have used the Yukawa effective interaction (YEI) in our study that has been successfully used in the calculations of EOS of NSM at finite temperature [1] and thermal evolution of properties of nuclear matter (NM) [2]. The temperature dependence of the mean fields and the interaction parts of the energy densities are simulated through the Fermi-Dirac momentum distribution functions while the interaction itself is temperature independent. Hence, in order to have the correct thermal evolution it is necessary to know the correct momentum dependence of the nucleonic mean fields. But this aspect of the nucleonic mean field has remained as a...
Physics of the Dark Universe, 2021
Fortschritte der Physik, 2021
International Journal of Geometric Methods in Modern Physics, 2020
A bouncing scenario is studied in the framework of generalized Brans–Dicke theory. In order to ha... more A bouncing scenario is studied in the framework of generalized Brans–Dicke theory. In order to have a dark energy (DE) driven late time cosmic acceleration, we have considered a unified dark fluid simulated by a linear equation of state (EoS). The evolutionary behavior of the DE equation of parameter derived from the unified dark fluid has been discussed. The effect of the bouncing scale factor on the Brans–Dicke parameter, self-interacting potential and the Brans–Dicke scalar field is investigated.
The European Physical Journal Plus, 2019
Astrophysics and Space Science, 2018
The European Physical Journal Plus, 2016
Communications in Physics, 2010
The European Physical Journal Plus, 2017
Advances in High Energy Physics, 2016
The energy and momentum of some diagonal anisotropic Bianchi type Universes are obtained using di... more The energy and momentum of some diagonal anisotropic Bianchi type Universes are obtained using different energy-momentum complexes in the framework of General Relativity. The Møller energy is found to be zero for all the Universes considered in the present work. In all other prescriptions, the energy and momentum vanish when the sum of the metric parametersαandβvanishes. This result obviously raises a question: why this specific choice? We have explored Tryon’s conjecture that the Universe must have a zero net value for all conserved quantities to get some ideas on this issue.
Plane symmetric bulk viscous string cosmological models with strange quark matter are investigate... more Plane symmetric bulk viscous string cosmological models with strange quark matter are investigated. We have incorporated bulk viscous pressure to study its affect on the properties of the model. Assuming an anisotropic relationship among the metric potentials, we have tried to put some constraints on the anisotropic parameter.
The European Physical Journal C, 2015
Journal of Physics G: Nuclear and Particle Physics, 2011
International Journal of Theoretical Physics, 2013
Anisotropic Locally Rotationally Symmetric Bianchi-I (LRSBI) cosmological model is investigated w... more Anisotropic Locally Rotationally Symmetric Bianchi-I (LRSBI) cosmological model is investigated with variable gravitational and cosmological constants in the framework of Einstein’s general relativity. The shear scalar is considered to be proportional to the expansion scalar. The dynamics of the anisotropic universe with variable G and Λ are discussed. Our calculations for the Supernova constraints concerning the luminosity distance provide reasonable results.
International Journal of Theoretical Physics, 2010
Page 1. Int J Theor Phys (2010) 49: 25692581 DOI 10.1007/s10773-010-0448-5 Bulk Viscous Bianchi-... more Page 1. Int J Theor Phys (2010) 49: 25692581 DOI 10.1007/s10773-010-0448-5 Bulk Viscous Bianchi-III Models with Time Dependent G and Dipanjali Behera · Sunil K. Tripathy · Tushar R. Routray Received: 23 May 2010 ...