Phantom cosmology in an extended theory of gravity

Tripathy, S. K.; Mishra, B.

doi:10.1016/j.cjph.2019.12.022

Cited by 37 publications

(21 citation statements)

References 80 publications

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“…There are good number of cosmological models presented in literature with f 1 (R) = R and f 2 (T) = 𝛽T, 𝛽 being the coupling constant. [38][39][40] Here we wish to incorporate the time in-dependent cosmological constant Λ 0 in f 2 (T), such that f (R, T) = R + 2𝛽T + 2Λ 0 . [41,42] We consider a flat FLRW space time…”

Section: F (R T) Gravity Field Equations In Frw Metricmentioning

confidence: 99%

Bouncing Cosmology in Extended Gravity and Its Reconstruction as Dark Energy Model

Agrawal

Tello‐Ortiz

Mishra

et al. 2021

Fortschritte der Physik

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In this paper, we have presented a bouncing cosmological model of the Universe in an extended theory of gravity. The dynamical behaviour of the model obtained from the flat FLRW space-time along with the violation of null energy condition have been shown. The geometrical parameters show singularity behaviour at the bouncing epoch. The parameters involved in the scale factor play a major role in the bouncing behaviour. In addition, the coupling parameter that resulted in the minimal matter-geometry coupling in the extended gravity has significant role to avoid the singularity of equation of state parameter at the bouncing epoch. Using a linear homogeneous perturbation calculation, we show the dynamical stability of the model.

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Section: F (R T) Gravity Field Equations In Frw Metricmentioning

confidence: 99%

Bouncing Cosmology in Extended Gravity and Its Reconstruction as Dark Energy Model

Agrawal

Tello‐Ortiz

Mishra

et al. 2021

Fortschritte der Physik

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“…But a more prominent approach to understanding this reversed pressure force is to modify the the Einstein theory of gravity known as general relativity (GR). To service this motivation, a lot of modifications of GR such as f (R) gravity, f (T ) gravity etc have been proposed [11][12][13]. Considering teleparallel equivalent of GR (TEGR) as a starting point, one can approach the modified gravity theory with matter-coupling.…”

Section: Introductionmentioning

confidence: 99%

A study of traversable wormhole solutions in extended teleparallel theory of gravity with matter coupling

et al. 2021

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This study is devoted to explore the physical aspects of wormhole geometry under embedded class-1 spacetime in $$f(T,\tau )$$ f ( T , τ ) gravity, where $$\tau $$ τ denotes the trace of the energy-momentum tensor and T is the torsion. We derive the embedded class-1 solutions by considering spherically symmetric static spacetime. The shape function is calculated in the framework of embedded class-1 spacetime. It is necessary to mention here that the calculated shape function can be used in other modified theories of gravity. To complete this study, we take diagonal and off-diagonal tetrad, and try to build a comparison by considering the validity region of energy conditions in embedded class-1 spacetime. The embedded surface diagram is given to understand the connection between the two different regions of spacetime. The validity regions of all the energy conditions are calculated. A detailed graphical analysis is provided for validity regions of all the energy conditions. The presence of exotic matter is confirmed in both the cases as the null energy condition is violated.

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“…Also the occurrence of superluminality may not be completely avoided. It has been shown earlier that, a regular bounce with spatial sections can only occur if the null energy condition ρ + p > 0 is violated in the purview of an extended gravity theory [64,73,76]. This is the primary motivation for using negative energy scalar fields with ghost condensates [77], conformal galileon [78] and other techniques to perform bounces, occasionally resulting in instabilities that must be addressed [79].…”

Section: Stability Analysismentioning

confidence: 99%

Matter Bounce Scenario and the Dynamical aspects in f(Q,T) Gravity

Agrawal,

Pati,

Tripathy

et al. 2021

Preprint

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In the context of the late time cosmic acceleration phenomenon, many geometrically modified theories of gravity have been proposed in recent times. In this paper, we have investigated the role of a recently proposed extension of symmetric teleparallel gravity dubbed as f (Q, T ) gravity in getting viable cosmological models, where Q and T respectively denote the non-metricity and the trace of energy momentum tensor. We stress upon the mathematical simplification of the formalism in the f (Q, T ) gravity and derived the dynamical parameters in more general form in terms of the Hubble parameter. We considered two different cosmological models mimicking non-singular matter bounce scenario. Since energy conditions play a vital role in providing bouncing scenario, we have analyzed different possible energy conditions to show that strong energy condition and null energy condition be violated in this theory. The models considered in the work are validated through certain cosmographic tests and stability analysis.

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Phantom cosmology in an extended theory of gravity

Cited by 37 publications

References 80 publications

Bouncing Cosmology in Extended Gravity and Its Reconstruction as Dark Energy Model

Bouncing Cosmology in Extended Gravity and Its Reconstruction as Dark Energy Model

A study of traversable wormhole solutions in extended teleparallel theory of gravity with matter coupling

Matter Bounce Scenario and the Dynamical aspects in f(Q,T) Gravity

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