Study of Particle Creation with Quadratic Equation of State in Higher Derivative Theory

2020 ◽  
Vol 50 (6) ◽  
pp. 725-743
Author(s):  
G. P. Singh ◽  
Ashwini R. Lalke ◽  
Nikhil Hulke
2013 ◽  
Vol 22 (13) ◽  
pp. 1350074 ◽  
Author(s):  
R. SHARMA ◽  
B. S. RATANPAL

A class of solutions describing the interior of a static spherically symmetric compact anisotropic star is reported. The analytic solution has been obtained by utilizing the Finch and Skea [Class. Quantum Grav.6 (1989) 467] ansatz for the metric potential grr which has a clear geometric interpretation for the associated background spacetime. Based on physical grounds, appropriate bounds on the model parameters have been obtained and it has been shown that the model admits an equation of state (EOS) which is quadratic in nature.


2021 ◽  
Vol 81 (1) ◽  
Author(s):  
S. Thirukkanesh ◽  
Robert S. Bogadi ◽  
Megandhren Govender ◽  
Sibusiso Moyo

AbstractWe investigate the stability and enhancement of the physical characteristics of compact, relativistic objects which follow a quadratic equation of state. To achieve this, we make use of the Vaidya–Tikekar metric potential. This gravitational potential has been shown to be suitable for describing superdense stellar objects. Pressure anisotropy is also a key feature of our model and is shown to play an important role in maintaining stability. Our results show that the combination of the Vaidya–Tikekar gravitational potential used together with the quadratic equation of state provide models which are favourable. In comparison with other equations of state, we have shown that the quadratic equation of state mimics the colour-flavour-locked equation of state more closely than the linear equation of state.


Author(s):  
Manuel Malaver ◽  
Hamed Kasmaei

Recent astronomical observations with respect to measurements in distant supernovas, cosmic microwave background and weak gravitational lensing confirm that the Universe is undergoing a phase of accelerated expansion and it has been proposed that this cosmological behavior is caused by a hypothetical dark energy which has a strong negative pressure that allows explain the expanding universe. Several theoretical ideas and models related dark the energy includes the cosmological constant, quintessence, Chaplygin gas, braneworld and tachyonic scalar fields. In this paper, we have obtained new relativistic stellar configurations considering an anisotropic fluid distribution with a charge distribution which could represents a potential model of a dark energy star. In order to investigate the effect of a quadratic equation of state in this anisotropic model we specify particular forms for the gravitational potential that allow solving the Einstein-Maxwell field equations. For these new solutions we checked that the radial pressure, metric coefficients, energy density, anisotropy factor, charge density , mass function are well defined and are regular in the interior of the star. The solutions found can be used in the development of dark energy stars models satisfying all physical acceptability conditions but the causality condition and strong energy condition are violated. We expect that these models have multiple applications in astrophysics and cosmology.


2020 ◽  
Vol 17 (05) ◽  
pp. 2050064 ◽  
Author(s):  
Rakesh Raushan ◽  
Ashutosh Singh ◽  
R. Chaubey ◽  
T. Singh

This paper deals with the dynamical systems analysis of Friedmann–Robertson–Walker (FRW) model of the Universe in the framework of general relativity with quadratic equation of state and bulk viscosity. The evolution equations are transformed into an autonomous system of differential equations using suitable variables transformation. Stability analysis of cosmological models with quadratic equation of state parameter are discussed in detail in two different scenarios viz, first Universe filled with barotropic fluid and second filled with bulk viscous fluid. The nature of critical points is analyzed for both cases accordance with respective eigenvalues. We have also analyzed the stable attractor for both cases and examined their properties from the point of cosmological view.


2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
G. P. Singh ◽  
Binaya K. Bishi

This paper deals with the study of Bianchi type-I universe in the context off(R,T)gravity. Einstein’s field equations inf(R,T)gravity have been solved in the presence of cosmological constantΛand quadratic equation of state (EoS)p=αρ2-ρ, whereα≠0is a constant. Here, we have discussed two classes off(R,T)gravity; that is,f(R,T)=R+2f(T)andf(R,T)=f1(R)+f2(T). A set of models has been taken into consideration based on the plausible relation. Also, we have studied some physical and kinematical properties of the models.


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