Constraints on a special running vacuum model

Geng, Chao–Qiang; Lee, Chung-Chi; Yin, Lu

doi:10.1140/epjc/s10052-020-7653-z

Cited by 17 publications

(17 citation statements)

References 58 publications

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“…Here, however, we will concentrate on the post-inflationary universe, where only the leading power ∼ H 2 is involved in the dynamics of ρ vac . A variety of phenomenological analyses have supported this possibility in recent years and within different approaches [13][14][15][16][17][18][19].…”

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confidence: 99%

“…An estimate of ν in QFT indicates that it is of order 10 −3 at most [31]. In the calculation of [6] these coefficients are expected to be of order ∼ M 2 X /m 2 Pl 1, where m Pl 1.22×10 19 GeV is the Planck mass and M X is of order of a typical Grand Unified Theory (GUT) scale, times a multiplicity factor accounting for the number of heavy particles in the GUT. We will be particularly interested in 1, but also considering the prior on H0 = (73.5 ± 1.4) km/s/Mpc from SH0ES [32].…”

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confidence: 99%

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Running vacuum against the H ₀ and σ₈ tensions

Peracaula

Gómez-Valent

Pérez

et al. 2021

EPL

179

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The cosmological term, Λ, was introduced 104 years ago by Einstein in his gravitational field equations. Whether Λ is a rigid quantity or a dynamical variable in cosmology has been a matter of debate for many years, especially after the introduction of the general notion of dark energy (DE). Λ is associated to the vacuum energy density, , and one may expect that it evolves slowly with the cosmological expansion. Herein we present a devoted study testing this possibility using the promising class of running vacuum models (RVMs). We use a large string SNIa+BAO+H(z)+LSS+CMB of modern cosmological data, in which for the first time the CMB part involves the full Planck 2018 likelihood for these models. We test the dependence of the results on the threshold redshift at which the vacuum dynamics is activated in the recent past and find positive signals up to for . The RVMs prove very competitive against the standard ΛCDM model and give a handle for solving the tension and alleviating the H 0 one.

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mentioning

confidence: 99%

mentioning

confidence: 99%

Running vacuum against the H ₀ and σ₈ tensions

Peracaula

Gómez-Valent

Pérez

et al. 2021

EPL

179

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“…The cosmological constant problem [55] has yet to be solved, despite much research in the area. One possibility is a dynamic cosmological parameter [56] which can fit the observations [57] or fit the observations even better than the standard ΛCDM model [58]. For t → 0 , the deceleration parameter q tends to be constant.…”

Section: Discussionmentioning

confidence: 99%

Anisotropic Cosmological Model in a Modified Theory of Gravitation

Tiwari¹,

Беешам

Mishra

et al. 2021

Universe

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Current observations indicate that, on a large enough scale, the universe is homogeneous and isotropic. However, this does not preclude the possibility of some anisotropy having occurred during the early stages of the evolution of the universe, which could then have been damped out later. This idea has aroused interest in the Bianchi models, which are homogeneous but anisotropic. Secondly, there is much interest in modified gravity these days due to the problems that the usual ΛCDM model faces in general relativity. Hence, in this paper, a study was conducted on the Bianchi type-I cosmological model in f(R,T)-modified gravity. Following some ideas from cosmography, a specific form of the deceleration parameter was assumed, leading to a model that exhibited a transition from early deceleration to late-time acceleration. The derived model approached isotropy at late times. The physical properties of the model were discussed, and expressions for the various parameters of the model were derived. It is also possible to make progress towards solving the cosmological constant problem, since in this model in f(R,T) gravity, a variable cosmological-type parameter arose, which was large early on but decreased to a constant value in later times.

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“…A closed Universe (k > 0) has a "spherical" curvature and has a defined surface area, for the homogeneity and isotropy. In this direction, we found in literature, the spatially flat" running vacuum model" (RVM) has been broadly explored [19]- [28]. In past [29,30], it has been proposed to solve the "coincidence problem", where the "cosmological constant" term is considered to be varying with the "Hubble parameter (H)".…”

Section: Introductionmentioning

confidence: 99%

Barrow HDE model for Statefinder diagnostic in non-flat FRW universe

Bharadwaj¹,

Pradhan²

2021

Preprint

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In this work we study a non-flat Friedmann-Robertson-Walker universe filled with a pressure-less dark matter (DM) and Barrow holographic dark energy (BHDE) whose IR cutoff is the apparent horizon. Among various DE models, (BHDE) model shows the dynamical enthusiasm to discuss the universe's transition phase. According to the new research, the universe transitioned smoothly from a decelerated to an accelerated period of expansion in the recent past. We exhibit that the development of q relies upon the type of spatial curvature. Here we study the equation of state (EoS) parameter for the BHDE model to determine the cosmological evolution for the non-flat universe. The (EoS) parameter and the deceleration parameter (DP) shows a satisfactory behaviour, it does not cross the the phantom line. We also plot the statefinder diagram to characterize the properties of the BHDE model by taking distinct values of barrow exponent △. Moreover, we likewise noticed the BHDE model in the (ω D − ω ′ D ) plane, which can furnish us with a valuable, powerful finding to the mathematical determination of the statefinder. In the statefinder trajectory, this model was found to be able to reach the ΛCDM fixed point.

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Constraints on a special running vacuum model

Cited by 17 publications

References 58 publications

Running vacuum against the H ₀ and σ₈ tensions

Running vacuum against the H ₀ and σ₈ tensions

Anisotropic Cosmological Model in a Modified Theory of Gravitation

Barrow HDE model for Statefinder diagnostic in non-flat FRW universe

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Constraints on a special running vacuum model

Cited by 17 publications

References 58 publications

Running vacuum against the H 0 and σ8 tensions

Running vacuum against the H 0 and σ8 tensions

Anisotropic Cosmological Model in a Modified Theory of Gravitation

Barrow HDE model for Statefinder diagnostic in non-flat FRW universe

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Product

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Running vacuum against the H ₀ and σ₈ tensions

Running vacuum against the H ₀ and σ₈ tensions