Accelerated cosmos in a nonextensive setup

Moradpour, H.; Bonilla, Alexander; Abreu, Éverton M. C.; Neto, Jorge Ananias

doi:10.1103/physrevd.96.123504

Cited by 132 publications

(101 citation statements)

References 102 publications

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“…We find remarkable differences between Einstein and Rastall gravities in cosmological solutions, as it has been recently shown in [40]. In addition, we emphasize that, from the cosmological point of view, Rastall hypothesis (mutual interaction between geometry and matter fields) cannot describe Dark Energy and one need to consider a Dark Energy-like source, just the same as Einstein GTR [21,40].…”

Section: : "The Question Which Remains Is How To Construct the Stressmentioning

confidence: 91%

“…In addition, we emphasize that, from the cosmological point of view, Rastall hypothesis (mutual interaction between geometry and matter fields) cannot describe Dark Energy and one need to consider a Dark Energy-like source, just the same as Einstein GTR [21,40]. In addition, one may describe the current era, by generalizing the Rastall hypothesis and without using a Dark Energy-like source [41].…”

Section: : "The Question Which Remains Is How To Construct the Stressmentioning

confidence: 99%

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Einstein and Rastall theories of gravitation in comparison

Darabi

Moradpour

Licata³

et al. 2018

Eur. Phys. J. C

Self Cite

178

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We profit by a recent paper of Visser claiming that Rastall gravity is equivalent to Einstein gravity to compare the two gravitational theories in a general way. Our conclusions are different from Visser's ones. We indeed argue that these two theories are not equivalent. In fact, Rastall theory of gravity is an "open" theory when compared to Einstein general theory of relativity. Thus, it is ready to accept the challenges of observational cosmology and quantum gravity.The framework of extended theories of gravity [1][2][3][4][5] is today considered an useful and popular approach to attempt to solve the important problems of the standard model of cosmology like Dark Energy [6,7] and Dark Matter [8,9]. A key point is that all of the potential alternatives to Einstein's general theory of relativity (GTR) must be viable. This implies that alternative theories must be in agreement with the Einstein's equivalence principle, which has today a strong, unchallengeable empirical evidence [2]. The fundamental consequence is that the alternatives to Einstein gravity must be metric theories [2]. Another important point is that such alternatives must pass the solar system tests. Hence, deviations from the standard GTR must be weak [1,2].Within the framework of extended gravity, one finds the theory proposed by Rastall in 1972 [10], which recently obtained a renewed interest in the literature [11][12][13][14]. This interest is due to some good behavior of the Rastall theory. In fact, on one hand it seems in good agreement with observational data on the Universe age and on the Hubble parameter [15]. On the other hand it may, in principle, provide an alternative description for the matter dominated era with respect to the GTR [16]. Observational data from the helium nucleosynthesis seem also in agreement with Rastall gravity [17]. Based on these observational evidences, there have been some recently studies of the various cosmic eras in the framework of Rastall gravity [18][19][20][21][22]. Other interesting a e-mail: cordac.galilei@gmail.com issues are that Rastall gravity seems to do not suffer from the entropy and age problems of standard cosmology [23] and is consistent with the gravitational lensing phenomena [24,25]. Further interesting works on Rastall gravity are given by [26][27][28][29][30] and references within.Differently from Einstein gravity, Rastall gravity considers a non-divergence-free energy-momentum . A different, but similar theory is the so called Curvature-matter theory of gravity [31][32][33][34][35]. In this theory the matter and geometry are coupled to each other in a non-minimal way [31][32][33][34][35]. Then, the standard energy-momentum conservation law does not work in this case too [31][32][33][34][35].In a recent paper [36], Visser claimed that Rastall gravity is equivalent to Einstein gravity. In this letter, we argue that these two theories are not equivalent instead. Let us see the key points of our interpretation.Rastall did not define a new energy-momentum tensor (EMT) in his origina...

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Section: : "The Question Which Remains Is How To Construct the Stressmentioning

confidence: 91%

Section: : "The Question Which Remains Is How To Construct the Stressmentioning

confidence: 99%

Einstein and Rastall theories of gravitation in comparison

Darabi

Moradpour

Licata³

et al. 2018

Eur. Phys. J. C

Self Cite

178

View full text Add to dashboard Cite

show abstract

“…These results show that the horizon entropy in the Rastall theory differs from that of the Einstein theory, a signal addressing us that their Lagrangian are also different [56][57][58][59][60][61]. In addition, it has also been shown that the Rényi entropy content of horizon can help us in providing a proper description for the current accelerated universe in both the Einstein and Rastall theory [62], an analysis which also reveals some differences between the cosmological features of the Rastall theory and those of the Einstein theory. It is also useful to mention here that the Rastall theory provides a proper platform for generalizing the unimodular gravity which leads to the interesting cosmological consequences [63].…”

Section: Introductionmentioning

confidence: 92%

Thermodynamics in Rastall gravity with entropy corrections

Bamba¹,

Jawad²,

Rafique³

et al. 2018

Eur. Phys. J. C

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We explore the thermodynamic analysis at the apparent horizon in the framework of Rastall theory of gravity. We take different entropies such as the Bakenstein, logarithmic corrected, power law corrected, and the Renyi entropies. We investigate the first law and generalized second law of thermodynamics analytically for these entropies which hold under certain conditions. Furthermore, the behavior of the total entropy in each case is analyzed. As a result, it is implied that the generalized second law of thermodynamics is satisfied. We also check whether the thermodynamic equilibrium condition for these entropies is met at the present horizon.

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“…We begin with the original Rastall model [2]. Since in the Rastall field equation (12) there appear no derivatives of the Ricci scalar, a comparison to equation (7) suggests a function of type…”

Section: A Suggestion For Lagrangian Of Rastall Gravities From F (R mentioning

confidence: 99%

A connection between Rastall-type and f(R, T) gravities

Shabani¹,

Ziaie²

2020

EPL

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Recently a Lagrangian formulation for Rastall Gravity (RG) has been proposed in the framework of f (R, T) gravity [1]. In the present work we obtain Lagrangian formulation for the standard Rastall theory assuming the matter content is a perfect fluid with linear Equation of State (EoS). We therefore find a relation between the coupling constant of the Lagrangian, the Rastall gravitational coupling constant and the EoS parameter. We also propose a Lagrangian for the Generalized Rastall Gravity (GRG). In this case the Rastall parameter which is a constant is replaced by a variable one. More exactly, it appears as a function of the Ricci scalar and the trace of the Energy Momentum Tensor (EMT). In both mentioned models, the Lagrangians are constructed by a linear function of R and T

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Accelerated cosmos in a nonextensive setup

Cited by 132 publications

References 102 publications

Einstein and Rastall theories of gravitation in comparison

Einstein and Rastall theories of gravitation in comparison

Thermodynamics in Rastall gravity with entropy corrections

A connection between Rastall-type and f(R, T) gravities

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