Cosmological bounce in a modified gravity framework

Chattopadhyay, Surajit

doi:10.1002/asna.20220103

Cited by 3 publications

(1 citation statement)

References 27 publications

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“…If it is extended, which means that if it is written as a function of

T

, i.e.,

f(T)

(Bamba, Myrzakulov, et al, 2012), then it is equivalent to

f(R)

Sotiriou (2006) in general relativity and thus realize the late‐time acceleration and/or the inflation. In a very recent study, Chattopadhyay (2023) demonstrated bounce realization in

f(T)

gravity with exponential and power‐law forms of scale factor and indicated the possibility of realization of nonsingular holographic bounce. Pre‐bounce ekpyrotic contraction under

f(R)

gravity and in presence of chameleon scalar field was reported in Karmakar et al (2020) and bounce realization of the universe with a form of Chaplygin gas in modified gravity framework was discussed in Chattopadhyay (2017), where the role of the model parameters of the modified Chaplygin gas was investigated before and after the bounce scenario.…”

Section: Introductionmentioning

confidence: 99%

A truncated scale factor to realize cosmological bounce under the purview of modified gravity

Chokyi

Chattopadhyay

2023

Astron Nachr

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The present paper reports a study on bounce realization with a truncated scale factor and the holographic fluid taken in the form of holographic Ricci Dark Energy, which is a particular case of holographic Nojiri–Odintsov model (Nojiri & Odintsov, 2006, Gen. Relativ. Gravit., 38(8), 1285). We have investigated the realization of bounce due to the application of a holographic fluid in the early scenario of the universe. We started with a de‐Sitter scale factor in our study and derived two modified forms using Taylor's series expansion. After studying the behavior of the resulting Hubble parameter, we identified as the suitable form of the scale factor to realize the bounce. It satisfied the conditions , , and before, at, and after the turn‐around point. We have also observed that the resulting equation of state (EoS) parameter violates the null energy condition required by the bounce realization. We have studied the bounce scenario in a modified gravity framework and derived the slow roll parameters. We have studied the behavior of the potential along with the slow‐roll parameters in this bouncing scenario.

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“…If it is extended, which means that if it is written as a function of

T

, i.e.,

f(T)

(Bamba, Myrzakulov, et al, 2012), then it is equivalent to

f(R)

Sotiriou (2006) in general relativity and thus realize the late‐time acceleration and/or the inflation. In a very recent study, Chattopadhyay (2023) demonstrated bounce realization in

f(T)

gravity with exponential and power‐law forms of scale factor and indicated the possibility of realization of nonsingular holographic bounce. Pre‐bounce ekpyrotic contraction under

f(R)

Section: Introductionmentioning

confidence: 99%

A truncated scale factor to realize cosmological bounce under the purview of modified gravity

Chokyi

Chattopadhyay

2023

Astron Nachr

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Generalized cutoff for late time acceleration and inflation: The cosmology of holographic fluid

Aziza,

Chattopadhyay

2023

Int. J. Geom. Methods Mod. Phys.

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Motivated by the work of Nojiri et al. [Phys. Lett. B 797 (2019) 134829], we utilize the holographic principle in the early universe to realize the holographic origin through inflation. A similar argument can be made for its well-researched late-time application, and the early-time horizon contraction naturally boosts holographic energy density at inflationary scales. After accounting for the IR cutoff adjustment and using holographic Ricci dark energy as the inflationary fluid, we have shown the significance of [Formula: see text] in the inflation realization. For holographic Ricci dark fluid’s potential to realize inflation, several restrictions were derived. The e-folding number was used to discuss inflationary observables and determine the slow-roll parameters. The study covered the effects of reconstructing the IR cutoff and the potential for inflation to be realized after taking into account holographic Ricci dark energy as a special instance of the most generalized Nojiri–Odintsov holographic dark energy [S. Nojiri and S. D. Odintsov, Gen. Relativ. Gravit. 38 (2006) 1285–1304]. Additionally, some time intervals for the potential of inflation have been calculated, and the behavior of the equation of state parameter has also been discussed.

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A Study on the Various Aspects of Bounce Realisation for Some Choices of Scale Factors

2023

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The current study examines the realisation of cosmic bounce in two situations involving two distinct scale factor selections, one of which is a scale factor already developed for bouncing and the other of which is a scale factor created by truncating a series expansion of a de Sitter scale factor. Generalized Chaplygin gas (GCG) is assumed to be the background fluid in both situations. When the scale factor is set to the first kind, the pre-bounce scenario’s GCG energy density decreases due to contraction, reaches its lowest point at t=0 during the bounce, and then rises as a result of expansion following the bounce. However, it is noted that the truncation has an impact on the density evolution from pre-bounce in the other scale factor scenario. The influence of bulk viscosity is shown in all circumstances, in addition to the influence of non-viscosity, and the test for stability makes use of the squared speed of sound. At the turn-around places, the null energy criterion is also violated. The final stage of the study includes a cosmographic analysis and a demonstration of the Hubble flow dynamics. In conclusion, we find that inflationary cosmology can also be realized with GCG as the background fluid for two-scale factor options. When the equivalent cosmic parameter is examined for pre-bounce and post-bounce scenarios, a symmetry is frequently seen. The symmetry occurs near the point of bouncing or turning.

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Cosmological bounce in a modified gravity framework

Cited by 3 publications

References 27 publications

A truncated scale factor to realize cosmological bounce under the purview of modified gravity

A truncated scale factor to realize cosmological bounce under the purview of modified gravity

Generalized cutoff for late time acceleration and inflation: The cosmology of holographic fluid

A Study on the Various Aspects of Bounce Realisation for Some Choices of Scale Factors

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