Dynamical system analysis of interacting dark energy-matter scenarios at the linearized inhomogeneous level

Sharma, Mohit Kumar; Sur, Sourav

doi:10.1016/j.dark.2023.101192

Cited by 6 publications

(5 citation statements)

References 80 publications

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“…Recasting cosmological equations into autonomous systems provides a method to investigate the universe's dynamics [15,[35][36][37][38]. We study the cosmological evolution searching for the critical points for a given dark energy potential.…”

Section: The Phase-space Analysismentioning

confidence: 99%

“…In this section, we explore the stability of the critical points outlined in Table 1. The aim is to verify if the derived cosmological solutions can behave as late time attractors [15,33,[35][36][37][38]47,48]. To this end, we evaluate the linear perturbations of the dynamical system and examine the sign of the eigenvalues of the Jacobian matrix associated with each critical point…”

Section: The Stability Analysismentioning

confidence: 99%

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Phase-space analysis in non-minimal symmetric-teleparallel dark energy

Carloni,

Luongo

2024

Eur. Phys. J. C

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We modify the symmetric-teleparallel dark energy through the addition of a further Yukawa-like term, in which the non-metricity scalar, Q, is non-minimally coupled to a scalar field Lagrangian where the phion acts as quintessence, describing dark energy. We investigate regions of stability and find late-time attractors. To do so, we conduct a stability analysis for different types of physical potentials describing dark energy, namely the power-law, inverse power-law, and exponential potentials. Within these choices, we furthermore single out particular limiting cases, such as the constant, linear and inverse potentials. For all the considered scenarios, regions of stability are calculated in terms of the signs of the coupling constant and the exponent, revealing a clear degeneracy among coefficients necessary to ensure stability. We find that a generic power-law potential with $$\alpha > 0$$ α > 0 is not suitable as a non-minimal quintessence potential and we put severe limits on the use of inverse potential, as well. In addition, the equations of state of each potential have been also computed. We find the constant potential seems to be favored than other treatments, since the critical point appears independent of the non-minimal coupling.

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Section: The Phase-space Analysismentioning

confidence: 99%

Section: The Stability Analysismentioning

confidence: 99%

Phase-space analysis in non-minimal symmetric-teleparallel dark energy

Carloni,

Luongo

2024

Eur. Phys. J. C

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“…In modified gravity theories, this parameter can assume different values, such as γ = 0.6875 in DGP theories and γ = 0.564 in scalar-tensor theories, for example [16]. However, some studies have been working on a time-dependent functional form of the growth index, γ = γ (z) [17,[21][22][23][24]. Therefore, one can probe the CDM model by measuring the growth index γ , because it has potential to distinguish GR and modified gravity models [21,[25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Reconstructing the growth index $$\gamma $$ with Gaussian processes

Oliveira,

Avila,

Bernui

et al. 2024

Eur. Phys. J. C

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Alternative cosmological models have been proposed to alleviate the tensions reported in the concordance cosmological model, or to explain the current accelerated phase of the universe. One way to distinguish between General Relativity and modified gravity models is using current astronomical data to measure the growth index $$\gamma $$ γ , a parameter related to the growth of matter perturbations, which behaves differently in different metric theories. We propose a model independent methodology for determining $$\gamma $$ γ , where our analyses combine diverse cosmological data sets, namely $$\{ f(z_i) \}$$ { f ( z i ) } , $$\{ [f\sigma _8](z_i) \}$$ { [ f σ 8 ] ( z i ) } , and $$\{ H(z_i) \}$$ { H ( z i ) } , and use Gaussian Processes, a non-parametric approach suitable to reconstruct functions. This methodology is a new consistency test for $$\gamma $$ γ constant. Our results show that, for the redshift interval $$0< z < 1$$ 0 < z < 1 , $$\gamma $$ γ is consistent with the constant value $$\gamma = 0.55$$ γ = 0.55 , expected in General Relativity theory, within $$2 \sigma $$ 2 σ confidence level (CL). Moreover, we find $$\gamma (z=0)$$ γ ( z = 0 ) = 0.311 $$\pm 0.144 $$ ± 0.144 and $$\gamma (z=0) = 0.609 \pm 0.200$$ γ ( z = 0 ) = 0.609 ± 0.200 for the reconstructions using the $$\{ f(z_i) \}$$ { f ( z i ) } and $$\{ [f\sigma _8](z_i) \}$$ { [ f σ 8 ] ( z i ) } data sets, respectively, values that also agree at a 2$$\sigma $$ σ CL with $$\gamma = 0.55$$ γ = 0.55 . Our methodology and analyses can be considered as an alternative approach in light of the current discussion in the literature that suggests a possible evidence for the growth index evolution.

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“…[4,5,15,16,[20][21][22][23][24][25][26][27] These theories have been extensively studied in the context of modified gravity. By introducing new degrees of freedom (DOF) through torsion or non-metricity, a range of fascinating phenomena has been revealed, especially in cosmological models, [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] studies have explored solutions related to black holes, [10,[46][47][48][49] as well as gravitational waves. [50][51][52][53] In ref.…”

Section: Introductionmentioning

confidence: 99%

Maxwell‐f(Q)$f(Q)$ Theory

Nashed

2024

Fortschritte der Physik

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Exploring the four‐dimensional AdS black hole is crucial within the framework of the AdS/CFT correspondence. In this research, four‐dimensional stationary and rotating AdS solutions in the framework of the gravitational theory are investigated, considering the charged scenario. Author's emphasis is on the power‐law ansatz, which consistent with observations and is deemed the most viable. Because this solution does not have an uncharged version or relate to general relativity, it falls into a new category, which derives its features from changes in non‐metricity and incorporates the Maxwell domain. The singularities of such a solution are analyzed, computing all the quantities of different curvature and non‐metricity invariants. Author's results indicate the presence of a central singularity, albeit with a softer nature compared to standard non‐metricity or Einstein general relativity, attributed to the influence of the effect of . Several physical characteristics of black hole from thermodynamics perspective and demonstrate the existence of an outer event horizon in addition to the inner Cauchy horizons are examined. However, under the conditions of sufficiently large electric charge, a naked singularity emerges. Finally, a class of rotating black hole in four‐dimensional gravity that are asymptotically anti‐de Sitter charged is derived.

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Dynamical system analysis of interacting dark energy-matter scenarios at the linearized inhomogeneous level

Cited by 6 publications

References 80 publications

Phase-space analysis in non-minimal symmetric-teleparallel dark energy

Phase-space analysis in non-minimal symmetric-teleparallel dark energy

Reconstructing the growth index $$\gamma $$ with Gaussian processes

Maxwell‐f(Q)$f(Q)$ Theory

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