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《New Astronomy》2021
A spatially homogeneous and anisotropic locally-rotationally-symmetric Bianchi type-I spacetime model with strange quark matter (SQM) and a variable cosmological term is studied in theory. The exact solutions are obtained for a particular form of under the law of variable deceleration parameter proposed by Banerjee et al (2005). The model presents a cosmological scenario of transition from early deceleration to late time acceleration. In the absence of gravity and SQM, accelerates the universe. In a specific case when vanishes at late times, the SQM accelerates the universe, even in the absence of gravity. The model shows the possibility that SQM could be an alternative to dark energy. The physical viability of the model costs the observational inconsistency. 相似文献
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《New Astronomy》2022
In this paper, we employ mimetic gravity coupled with Lagrange multiplier and mimetic potential to yield viable inflationary cosmological solutions consistent with latest Planck and BICEP2/Keck Array data. We present here three viable inflationary solutions of the Hubble parameter () represented by , , and , where , , , , are free parameters, and represents the number of e-foldings. We carry out the analysis with the simplest minimal function of the form , where is the model parameter. We report that for the chosen gravity model, viable cosmologies are obtained compatible with observations by conveniently setting the Lagrange multiplier and the mimetic potential. 相似文献
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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