Energy condition in unimodular f(R, T) gravity

Rajabi, Fateme; Nozari, Kourosh

doi:10.1140/epjc/s10052-021-08972-6

Cited by 16 publications

(7 citation statements)

References 80 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Capozziello et al [16] studied the role of the energy conditions in f (R) gravity. Studies involving the energy conditions have been undertaken in non-minimally coupled f (R, T) gravity [17], symmetric f (Q, T) gravity [18], unimodular F(R, T) gravity [19], and others. In a recent detailed analysis, Kontou and Sanders [20] considered the equations of motion in relation to the energy conditions in general relativity and quantum field theory.…”

Section: Introductionmentioning

confidence: 99%

Inhomogeneous and Radiating Composite Fluids

Brassel

Maharaj

Goswami

2021

Entropy

View full text Add to dashboard Cite

We consider the energy conditions for a dissipative matter distribution. The conditions can be expressed as a system of equations for the matter variables. The energy conditions are then generalised for a composite matter distribution; a combination of viscous barotropic fluid, null dust and a null string fluid is also found in a spherically symmetric spacetime. This new system of equations comprises the energy conditions that are satisfied by a Type I fluid. The energy conditions for a Type II fluid are also presented, which are reducible to the Type I fluid only for a particular function. This treatment will assist in studying the complexity of composite relativistic fluids in particular self-gravitating systems.

show abstract

Section: Introductionmentioning

confidence: 99%

Inhomogeneous and Radiating Composite Fluids

Brassel

Maharaj

Goswami

2021

Entropy

View full text Add to dashboard Cite

show abstract

“…Following our previous construction of the Unimodular f (R, T ) gravity [98] and the Energy Conditions in Unimodular f (R, T ) gravity [118], in this paper we reconsidered cosmological inflation and the issue of reheating in the unimodular f (R, T ) gravity. At the first step, we analyzed in details the embedding of cosmological inflation within unimodular f (R, T ) gravity.…”

Section: Discussionmentioning

confidence: 99%

“…In this paper, we investigate cosmic inflation and reheating stage in the context of our proposed unimodular f (R, T ) gravity [98] (see also [118] for the energy conditions in this modified gravity scenario). By adopting the Jordan frame, we study the slow roll inflation, the rapid oscillation phase, the radiation dominated and the recombination eras and calculate the e-folds numbers during these epochs.…”

Section: Introductionmentioning

confidence: 99%

Reheating and particle creation in unimodular f(R, T) gravity

Rajabi¹,

Nozari²

2022

Preprint

View full text Add to dashboard Cite

We study cosmological inflation and reheating in the unimodular f (R, T ) gravity. During the reheating era, which takes place just after the end of inflation, the energy density of inflaton is converted to radiation energy through, for instance, rapid oscillation about the minimum of the potential. We quantify our investigation by calculating the reheating temperature. This quantity is written in terms of the spectral index and the power spectrum, which provides a suitable framework to constrain the parameter space of the model. We discuss the massless particle creation for a spatially flat, homogeneous and isotropic universe in the context of unimodular f (R, T ) gravity. We obtain the number of created particles per unit volume of space. In order to avoid the complexity of field equations, we conformally transform in Einstein frame and investigate the reheating by considering some specific illustrative examples. Also we obtain the corresponding analytical solutions in addition to some numerical estimations.

show abstract

“…As it was noticed in the earlier works (see extensive discussion on the subject in [25,26] and references therein), NEC arise as a minimal requirement of both WEC and SEC and needs to be validated everywhere if matter is considered to be viable. Aforementioned energy conditions could be easily written down in the terms of energy density and anisotropic pressure (those definitions could be obtained from the timelike and null-like Raychaudhuri equations, derivation of which could be found in the papers [27,28]):…”

Section: Mit Bag Eos and Compact Starsmentioning

confidence: 99%

Buchdahl quark stars within f(Q) theory

et al. 2022

View full text Add to dashboard Cite

In the present paper, authors study the strange stars with the MIT Bag EoS admitting Buchdahl symmetry (non-singular and physically viable metric potential) in the both linear f (Q) = aQ + b and non-linear f (Q) = Q + aQ b forms of modified symmetric teleparallel gravitation. In order to obtain the correct form of Buchdahl metric coefficients, they matched interior strange star spacetime with the exterior Schwarzschild vacuum spacetime. As a strange star candidate, PSRJ1416-2230 has been used with mass M = 1.69M and radius R = 9.69R . For either linear and non-linear f (Q) gravities, they probed Null, Dominant and Strong Energy Conditions as well as the radial, tangential Equation of State (EoS), gradients of the perfect fluid energy-momentum tensor elements, Tolman-Oppenheimer-Volkoff equilibrium condition, relativistic adiabatic index and causality conditions, surface redshift. It was found that strange stars in the linear and non-linear f (Q) gravity show physically viable behavior, respect energy and causality conditions, has EoS in the bounds 0 ≤ ω ≤ 1 and surface redshift does not exceed 2, as expected.

show abstract

Energy condition in unimodular f(R, T) gravity

Cited by 16 publications

References 80 publications

Inhomogeneous and Radiating Composite Fluids

Inhomogeneous and Radiating Composite Fluids

Reheating and particle creation in unimodular f(R, T) gravity

Buchdahl quark stars within f(Q) theory

Contact Info

Product

Resources

About