Accelerated expansion from cosmological holography

Putten, Maurice H. P. M. van

doi:10.1093/mnrasl/slv038

Cited by 20 publications

(4 citation statements)

References 33 publications

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“…Here, Q 0 2.5 [12] is representative a near-extremal value of H(z) today. The associated relatively high estimate of H 0 from the cosmological data {z k , H(z k )} is free of tension with H 0 = 73.24 ± 1.74km s −1 Mpc −1 obtained from surveys of the Local Universe, providing quantitative support for a dynamic dark energy (8 …”

Section: Accelerated Expansion In Cosmological Holographymentioning

confidence: 99%

Accelerated cosmological expansion without tension in the Hubble parameter

Putten

2018

EPJ Web Conf.

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The first is found to be free of tension with H 0 from local surveys, while the latter is disfavored at 2.7σ. A further confrontation obtains in galaxy dynamics by a finite sensitivity of inertia to background cosmology in weak gravity, putting an upper bound of m 10 −30 eV on the mass of dark matter. A C 0 onset to weak gravity at the de Sitter scale of acceleration a dS = cH(z), where c denotes the velocity of light, can be seen in galaxy rotation curves covering 0 z 2. Weak gravity in galaxy dynamics hereby provides a proxy for cosmological evolution.

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Section: Accelerated Expansion In Cosmological Holographymentioning

confidence: 99%

Accelerated cosmological expansion without tension in the Hubble parameter

Putten

2018

EPJ Web Conf.

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“…This mechanism also explains why a 0 ∼ cH 0 as already noted by Milgrom (1983a). I also note that a similar approach has been discussed by van Putten (2014) in the specific context of de-Sitter space (but see also van Putten 2015).…”

Section: Discussionmentioning

confidence: 73%

Milgrom’s Law and Λ’s Shadow: How Massive Gravity Connects Galactic and Cosmic Dynamics

Trippe¹

2015

Journal of The Korean Astronomical Society

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Abstract:Massive gravity provides a natural solution for the dark energy problem of cosmology and is also a candidate for resolving the dark matter problem. I demonstrate that, assuming reasonable scaling relations, massive gravity can provide for Milgrom's law of gravity (or "modified Newtonian dynamics") which is known to remove the need for particle dark matter from galactic dynamics. Milgrom's law comes with a characteristic acceleration, Milgrom's constant, which is observationally constrained to a 0 ≈ 1.1 × 10 −10 m s −2 . In the derivation presented here, this constant arises naturally from the cosmologically required mass of gravitons like a 0 ∝ c √ Λ ∝ cH 0 √ 3Ω Λ , with Λ, H 0 , and Ω Λ being the cosmological constant, the Hubble constant, and the third cosmological parameter, respectively. My derivation suggests that massive gravity could be the mechanism behind both, dark matter and dark energy.

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“…This may be an attractive consequence regarding the swampland criteria on cosmology [103]. Although different scenarios with variable cosmological constant have been proposed beyond ΛCDM [104][105][106][107][108], diffusion provides a rich phenomenology dispensing from additional fields and higher-curvature corrections to the Einstein-Hilbert action.…”

Section: Conclusion and Further Remarksmentioning

confidence: 99%

Diffusion in unimodular gravity: Analytical solutions, late-time acceleration, and cosmological constraints

Corral,

Cruz,

González

2020

Preprint

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Unimodular gravity is an appealing approach to address the cosmological constant problem. In this scenario, the vacuum energy density of quantum fields does not gravitate and the cosmological constant appears merely as an integration constant. Recently, it has been shown that energy diffusion that may arise in quantum gravity and in theories with spontaneous collapse is compatible with this framework by virtue of its restricted diffeomorphism invariance. New studies suggest that this phenomenon could lead to higher-order equations in the context of homogeneous and isotropic Universe, affecting the well-posedness of their Cauchy initial-value problem. In this work, we show that this issue can be circumvented by assuming an equation of state that relates the energy density to the function that characterizes diffusion. As an application, we solve the field equations analytically for an isotropic and homogeneous Universes in a barotropic model and in the mass-proportional continuous spontaneous localization (CSL) scenario, assuming that only dark matter develops energy diffusion. Different solutions possessing phase transition from decelerated to accelerated expansion are found. We use cosmological data of type Ia Supernovae and observational Hubble data to constrain the free parameters of both models. It is found that very small but nontrivial energy nonconservation is compatible with the barotropic model. However, for the CSL model, we find that the best-fit values are not compatible with previous laboratory experiments. We comment on this fact and propose future directions to explore energy diffusion in cosmology.

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Accelerated expansion from cosmological holography

Cited by 20 publications

References 33 publications

Accelerated cosmological expansion without tension in the Hubble parameter

Accelerated cosmological expansion without tension in the Hubble parameter

Milgrom’s Law and Λ’s Shadow: How Massive Gravity Connects Galactic and Cosmic Dynamics

Diffusion in unimodular gravity: Analytical solutions, late-time acceleration, and cosmological constraints

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