Can varying the gravitational constant alleviate the tensions?

Sakr, Z.; Sapone, Domenico

doi:10.1088/1475-7516/2022/03/034

Cited by 19 publications

(12 citation statements)

References 68 publications

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“…It has been shown by [18] that gravitational transitions with high z t are unable to resolve the cosmological tensions.…”

Section: Data Availability Statementmentioning

confidence: 99%

Is the Hubble Crisis Connected with the Extinction of Dinosaurs?

Perivolaropoulos

2022

Universe

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It has recently been suggested that a gravitational transition of the effective Newton’s constant Geff by about 10%, 50–150 Myrs ago could lead to the resolution of both the Hubble crisis and the growth tension of the standard ΛCDM model. Hints for such an abrupt transition with weaker gravity at times before the transition, have recently been identified in Tully–Fisher galactic mass-velocity data, and also in Cepheid SnIa calibrator data. Here we use Monte-Carlo simulations to show that such a transition could significantly increase (by a factor of 3 or more) the number of long period comets (LPCs) impacting the solar system from the Oort cloud (semi-major axis of orbits ≳104AU). This increase is consistent with observational evidence from the terrestrial and lunar cratering rates, indicating that the impact flux of kilometer sized objects increased by at least a factor of 2 over that last 100 Myrs compared to the long term average. This increase may also be connected with the Chicxulub impactor event that produced the Cretaceous–Tertiary (K-T) extinction of 75% of life on Earth (including dinosaurs) about 66 Myrs ago. We use Monte-Carlo simulations to show that for isotropic Oort cloud comet distribution with initially circular orbits, random velocity perturbations (induced e.g., by passing stars and/or galactic tidal effects), lead to a deformation of the orbits that increases significantly when Geff increases. A 10% increase in Geff leads to an increase in the probability of the comets to enter the loss cone and reach the planetary region (pericenter of less than 10 AU) by a factor that ranges from 5% (for velocity perturbation much smaller than the comet initial velocity) to more than 300% (for total velocity perturbations comparable with the initial comet velocity).

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“…It has been shown by [18] that gravitational transitions with high z t are unable to resolve the cosmological tensions.…”

Section: Data Availability Statementmentioning

confidence: 99%

Is the Hubble Crisis Connected with the Extinction of Dinosaurs?

Perivolaropoulos

2022

Universe

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“…On the minimal assumption that the coupling G 4 (φ) evolves linearly with cosmic time, while employing model agnostic techniques for the Quintessence sector, G 2 (φ, X) = X−V (φ), we show in section 3 that any increase in H 0 is expected to be negligible. In other words, despite ongoing debate about whether non-minimal couplings can alleviate H 0 tension [71][72][73], in line with [67,74], we find that a non-minimal coupling can only marginally alleviate H 0 tension, at least within reasonable assumptions. Concretely, we observe that the class of models largely fails to penetrate into the phantom regime w DE < −1 at z = 0, so it is consistent with our (w 0 , w a ) expectations.…”

Section: Jcap04(2022)004mentioning

confidence: 48%

Is local H₀at odds with dark energy EFT?

Lee

Colgáin

et al. 2022

J. Cosmol. Astropart. Phys.

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Local H_0 determinations currently fall in a window between H 0 ∼ 70 km/s/Mpc (TRGB) and H 0 ∼ 76 km/s/Mpc (Tully-Fisher). In contrast, BAO data calibrated in an early ΛCDM universe are largely consistent with Planck-ΛCDM, H 0 ∼ 67.5 km/s/Mpc. Employing a generic two parameter family of evolving equations of state (EoS) for dark energy (DE) w DE(z) and mock BAO data, we demonstrate that if i) w DE(z = 0) < -1 and ii) integrated DE density less than ΛCDM, then H 0 increases. EoS that violate these conditions at best lead to modest H 0 increases within 1σ. Tellingly, Quintessence and K-essence satisfy neither condition, whereas coupled Quintessence can only satisfy ii). Beyond these seminal DE Effective Field Theories (EFTs), we turn to explicit examples. Working model agnostically in an expansion in powers of redshift z, we show that Brans-Dicke/f(R) and Kinetic Gravity Braiding models within the Horndeski class can lead to marginal and modest increases in H 0, respectively. We confirm that as far as increasing H 0 is concerned, no DE EFT model can outperform the phenomenological two parameter family of the DE models. Evidently, the late universe may no longer be large enough to accommodate H 0, BAO and DE described by EFT.

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“…This assumption is reminiscent of what happens to w EDE in EDE models. Similar transitions in the Planck Mass have been also considered during inflation (Ashoorioon et al 2014), during the matter-dominated epoch (Sakr & Sapone 2022), and at very low redshift (Marra & Perivolaropoulos 2021;Alestas et al 2022). More complex parameterizations are possible; for instance, one could explore the case of a double transition in M å at both early and late times.…”

Section: Parameterizing the Eft Functionsmentioning

confidence: 63%

An Exploration of an Early Gravity Transition in Light of Cosmological Tensions

Benevento

Kable

Addison

et al. 2022

ApJ

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We study a step-like transition in the value of the effective Planck mass (or effective gravitational constant) on cosmological scales prior to recombination. We employ cosmic microwave background, baryon acoustic oscillations, and Type Ia supernova data and find they are sufficient to strongly constrain our implementation of the effective field theory of dark energy and modified gravity, used to model the transition, to a limited parameter space. The data prefer a ∼5% shift in the value of the effective Planck mass (<10% at 2σ) prior to recombination. This Transitional Planck Mass (TPM) model is free to undergo its transition at any point over multiple decades of scale factor prior to recombination, log 10 ( a ) = − 5.32 − 0.72 + 0.96 (68% confidence level). This lowers the sound horizon at last scattering, which increases the Hubble constant to 71.09 ± 0.75 km s−1 Mpc−1 with a combination of local measurements as prior and to 69.22 − 0.86 + 0.67 km s−1 Mpc−1 when the prior is excluded. The TPM model improves χ 2 with respect to ΛCDM by Δχ 2 = −23.72 with the H 0 prior and Δχ 2 = −4.8 without the prior. The model allows for both H 0 > 70 kms−1 Mpc−1 and S 8 < 0.80 simultaneously with lower values of S 8 due to a reduction in the matter density Ω m to offset the increase in H 0 relative to ΛCDM. While this is a particular modified gravity model, studying other variants of modified gravity may be a productive path for potentially resolving cosmological tensions while avoiding the need for a cosmological constant.

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Can varying the gravitational constant alleviate the tensions?

Cited by 19 publications

References 68 publications

Is the Hubble Crisis Connected with the Extinction of Dinosaurs?

Is the Hubble Crisis Connected with the Extinction of Dinosaurs?

Is local H₀at odds with dark energy EFT?

An Exploration of an Early Gravity Transition in Light of Cosmological Tensions

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Can varying the gravitational constant alleviate the tensions?

Cited by 19 publications

References 68 publications

Is the Hubble Crisis Connected with the Extinction of Dinosaurs?

Is the Hubble Crisis Connected with the Extinction of Dinosaurs?

Is local H0at odds with dark energy EFT?

An Exploration of an Early Gravity Transition in Light of Cosmological Tensions

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Product

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Is local H₀at odds with dark energy EFT?