Linear density perturbations in multifield coupled quintessence

Leithes, Alexander; Malik, Karim A.; Mulryne, David J.; Nunes, Nelson J.

doi:10.1103/physrevd.95.123519

Cited by 12 publications

(15 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A same initial 3-velocityv (i) is assumed for all fluids. We have employed adiabatic initial conditions which imply δ c = 3 4 δ r initially [80]. The parameters and initial conditions are taken the same as in the previous section, i.e, {α = 15M −2 P , β = 15M −2 P , V 0 = 0.691 × 3H 2 0 M 2 P = 2.74 × 10 −47 GeV 4 }, and (31).…”

Section: Linear Perturbationsmentioning

confidence: 99%

“…One can attribute this acceleration to an exotic matter with negative pressure that permeates the Universe homogeneously, dubbed dark energy. A simple candidate for dark energy is a scalar field known as quintessence, which constitutes nearly 70% of our present Universe with density ρ dark ∼ 10 −10 eV 4 [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Structure formation requires that the acceleration begin after the matter-dominated era.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mass varying neutrinos, symmetry breaking, and cosmic acceleration

Sadjadi

Anari

2017

Phys. Rev. D

View full text Add to dashboard Cite

We introduce a new proposal for the onset of cosmic acceleration based on mass-varying neutrinos. When massive neutrinos become nonrelativistic, the $Z_2$ symmetry breaks, and the quintessence potential becomes positive from its initially zero value. This positive potential behaves like a cosmological constant at the present era and drives the Universe's acceleration during the slow roll evolution of the quintessence. In contrast to $\Lambda$CDM model, the dark energy in our model is dynamical, and the acceleration is not persistent. Contrary to some of the previous models of dark energy with mass-varying neutrinos, we do not use the adiabaticity condition which leads to instability.Comment: 24 pages, 7 figures, typos fixed, accepted by Physical Review

show abstract

Section: Linear Perturbationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mass varying neutrinos, symmetry breaking, and cosmic acceleration

Sadjadi

Anari

2017

Phys. Rev. D

View full text Add to dashboard Cite

show abstract

“…The presence of the scalar field adds an expansion friction term proportional toφ and the emergence of a fifth force, where the CDM component experiences an effective gravitational constant G eff = G N (1 + 2β 2 ) [18,61]. The balance of these two effects has a direct impact on the growth rate of the matter perturbations [62,63]. In the present work, the background is fixed in order to reproduce ΛCDM.…”

Section: Spherical Collapsementioning

confidence: 99%

Spherical collapse in coupled quintessence with a ΛCDM background

2020

Self Cite

View full text Add to dashboard Cite

In this work we study the growth of cold dark matter density perturbations in the nonlinear regime on a conformally coupled quintessence model in which the background is designed to mimic a ΛCDM cosmology. The spherical collapse of overdense regions is analysed. We highlight the role of the coupling on the overall dynamics, trace the evolution of the density contrast throughout the cosmic history and compute perturbative parameters such as the critical density contrast. We find that the coupling has the influence of delaying the collapse due to the slower growth of matter perturbations. We follow to compute the cluster number counts using the Press-Schechter and Sheth-Tormen mass functions. In both cases, the transfer of energy between the dark energy field and dark matter suppresses the number of objects at low redshifts and enhances the number at high redshifts. Finally, we compute the expected cluster number counts for two future surveys -eROSITA and the South Pole Telescope -and shed some light on the possibility of discriminating models with these missions.

show abstract

“…In the literature, a large number of theories regarding dark energy either impose the couplings at the level of the field equations [28][29][30][31][32] or they arise through a scalartensor type theory [18]. A structured Lagrangian formalism for coupled quintessence was examined in [33,34] where the matter species were coupled to a function solely of the field.…”

Section: Introductionmentioning

confidence: 99%

Kinetically coupled dark energy

Barros

2019

Phys. Rev. D

View full text Add to dashboard Cite

The main goal of this work is to propose a generalized model of interacting dark energy which allows for the kinetic term of a scalar field to couple to the matter species a priori in the action. We derive the modified field equations, and present novel cosmological solutions for a specific coupled model. One alluring consequence is the emergence of solutions allowing for an early scaling regime, possible due to two novel critical points, followed by a period of accelerated expansion. Using a dynamical system analysis, we show that the presence of the coupling may alter the dynamical nature of the critical points and can be used to enlarge the existence and stability regions of these. Using constraints from Planck data we are able to find an upper bound on the coupling parameter. Finally, it is shown how this theory encapsulates a wide variety of dark energy models already present in the literature.

show abstract

Linear density perturbations in multifield coupled quintessence

Cited by 12 publications

References 61 publications

Mass varying neutrinos, symmetry breaking, and cosmic acceleration

Mass varying neutrinos, symmetry breaking, and cosmic acceleration

Spherical collapse in coupled quintessence with a ΛCDM background

Kinetically coupled dark energy

Contact Info

Product

Resources

About