Dark energy anisotropic stress and large scale structure formation

Koivisto, Tomi S.; Mota, David F.

doi:10.1103/physrevd.73.083502

Cited by 306 publications

(279 citation statements)

References 84 publications

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“…Given that the understanding the evolution of dark energy perturbations is crucial to making precise predictions for the observed power spectra, a variety of phenomenological models have been discussed [26,27,29,30,31]. In this section we attempt to make some contact between our work and these models.…”

Section: F Comparison To Generalized Fluid Systemsmentioning

confidence: 99%

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Cosmological perturbations in elastic dark energy models

Battye

Moss

2007

Phys. Rev. D

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We discuss the general framework for a perfect continuum medium in cosmology and show that an interesting generalization of the fluids normally used is for the medium to have rigidity and, hence, be analogous to an elastic solid. Such models can provide perfect, adiabatic fluids which are stable even when the pressure is negative, if the rigidity is sufficiently large, making them natural candidates to describe the dark energy. In fact, if the medium is adiabatic and isotropic, they provide the most general description of linearized perturbations. We derive the equations of motion and wave propagation speeds in the isotropic case. We point out that anisotropic models can also be incorporated within the same formalism and that they are classified by the standard Bravais Lattices. We identify the adiabatic and isocurvature modes allowed in both the scalar and vector sectors and discuss the predictions they make for CMB and matter power spectra. We comment on the relationship between these models and other fluid-based approaches to dark energy, and discuss a possible microphysical manifestation of this class of models as a continuum description of defect-dominated scenarios.

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Section: F Comparison To Generalized Fluid Systemsmentioning

confidence: 99%

“…The idea of generalized dark matter/energy has been considered previously by a number of authors [19,20,26,27,29,30,31]. We will attempt to discuss how the approaches suggested by others relate to those presented here.…”

Section: Introductionmentioning

confidence: 99%

Cosmological perturbations in elastic dark energy models

Battye

Moss

2007

Phys. Rev. D

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“…For example, if the Ricci curvature scalar R in the GR spacetime action S ∝ d 4 x √ −gR is replaced by a function f (R), then Ψ and Φ are generically unequal. In the forecasts of §8 we focus on GR-deviations described by the G 9 and ∆γ parameters that characterize structure growth ( §2.2), but an alternative approach parametrizes the ratios of Ψ and Φ to their GR-predicted values (see Koivisto and Mota 2006;Bean and Tangmatitham 2010;Daniel and Linder 2010, and references therein). The G 9 and ∆γ formulation is well matched to observables that can be measured by large surveys, but the potentials formulation is arguably closer to the physics of modified gravity.…”

Section: Other Tests Of Modified Gravitymentioning

confidence: 99%

Observational probes of cosmic acceleration

et al. 2013

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The accelerating expansion of the universe is the most surprising cosmological discovery in many decades, implying that the universe is dominated by some form of "dark energy" with exotic physical properties, or that Einstein's theory of gravity breaks down on cosmological scales. The profound implications of cosmic acceleration have inspired ambitious efforts to understand its origin, with experiments that aim to measure the history of expansion and growth of structure with percent-level precision or higher. We review in detail the four most well established methods for making such measurements: Type Ia supernovae, baryon acoustic oscillations (BAO), weak gravitational lensing, and the abundance of galaxy clusters. We pay particular attention to the systematic uncertainties in these techniques and to strategies for controlling them at the level needed to exploit "Stage IV" dark energy facilities such as BigBOSS, LSST, Euclid, and WFIRST. We briefly review a number of other approaches including redshift-space distortions, the Alcock-Paczynski effect, and direct measurements of the Hubble constant H 0 . We present extensive forecasts for constraints on the dark energy equation of state and parameterized deviations from General Relativity, achievable with Stage III and Stage IV experimental programs that incorporate supernovae, BAO, weak lensing, and cosmic microwave background data. We also show the level of precision required for clusters or other methods to provide constraints competitive with those of these fiducial programs. We emphasize the value of a balanced program that employs several of the most powerful methods in combination, both to cross-check systematic uncertainties and to take advantage of complementary information. Surveys to probe cosmic acceleration produce data sets that support a wide range of scientific investigations, and they continue the longstanding astronomical tradition of mapping the universe in ever greater detail over ever larger scales.

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“…This model allows an analytical treatment and its 2 Though our present approach is phenomenological and not aimed at explaining the origin of dark matter stress Π, we might note that cosmic media satisfying effectively w = 0 but Π = 0 has indeed been considered [43]. (See also [44] for a recent discussion anisotropically stressed cosmological fluids and [36] for an extensive review of structure formation with generalized dark matter).…”

Section: A Specific Example Escaping the Constraintsmentioning

confidence: 99%

Viable Palatini-f(R)cosmologies with generalized dark matter

Koivisto

2007

Phys. Rev. D

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113

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We study the formation of large-scale structure in universes dominated by dark matter and driven to accelerated expansion by f(R) gravity in the Palatini formalism. If the dark matter is cold, practically all of these models are ruled out because they fail to reproduce the observed matter power spectrum. We point out that if the assumption that dark matter is perfect and pressureless at all scales is relaxed, nontrivial alternatives to a cosmological constant become viable within this class of modified gravity models.

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Dark energy anisotropic stress and large scale structure formation

Cited by 306 publications

References 84 publications

Cosmological perturbations in elastic dark energy models

Cosmological perturbations in elastic dark energy models

Observational probes of cosmic acceleration

Viable Palatini-f(R)cosmologies with generalized dark matter

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