共查询到20条相似文献，搜索用时 31 毫秒
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《New Astronomy》2021
The present study deals with a Tsallis holographic dark energy model in a flat Friedmann-Lamatire-Rbertson-Walker space-time geometry in the context of higher derivative theory of gravity. We have solved the field equations by applying energy conservation-law in non-interacting case and have obtained such a scale factor where is called as model parameter which shows transit phase evolution of the universe (decelerating to accelerating). Using this scale factor we have obtained the various cosmological parameters viz. Hubble parameter , deceleration parameter (DP) , jerk , snap , lerk and max-out . Constraining on Hubble parameters by the observational data of we have obtained the present values of , and and by using these constrained values, we have studied other cosmological parameters. Taking the constant equation of state (EoS) for ordinary matter, we have investigated the effective behaviour of various cosmological parameters and energy conditions in our model. We have observed the present values of and discussed with CDM model. We have found the age of the present universe Gyrs, present value of DP and transition point which are compatible with several observational results. 相似文献
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《New Astronomy》2021
We revisit the evolution of the scale factor in a flat FLRW spacetime with a new generalized decay rule for the dynamic -term under modified theories of gravity. It analyzes certain cosmological parameters and examines their behaviours in this generalized setting which includes several decay laws in the literature. We have also obtained observational constraints on various model parameters and estimated the present values of cosmological parameters , , , and have discussed with various observational results. Finite time past and future singularities in this model are also discussed. 相似文献
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《New Astronomy》2024
In this study, we investigate the impact of a plasma environment on gravitational weak lensing around a black hole from the perspective of T-duality. Our results demonstrate that the deflection angle of light rays around the black hole is notably affected by the parameter , with an increase leading to a decrease in the deflection angle, while the effect of plasma on the deflection angle is the opposite. We also consider different types of plasma distributions, including uniform , Singular Isothermal Sphere medium, and Non-Singular Isothermal gas sphere plasma. We have analyzed the total magnification of the image source due to gravitational weak lensing, taking into account the effect of parameter related to T-duality in the presence of plasma around the black hole. 相似文献
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《New Astronomy》2024
The study of thermodynamics in the background of the “extended uncertainty principle (EUP)” comes into interest in recent eras. In this article, we consider a charged black hole (BH) in higher dimensional space–time and present the thermodynamic parameters, based on a semiclassical framework, initially. Then we extend the same within the EUP background. We also analyze the criticality and find the critical points ( and ) when criticality appears. We study the effects of EUP on phase transition for higher dimensions () by plotting the diagrams. Further, we investigate the stability (thermal and global) of the BHs by employing the specific heat and the Gibbs free energy without and within EUP correction and compare the results with the Schwarzschild BHs in higher dimensions. 相似文献
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