The Vainshtein mechanism in the cosmic web

Falck, Bridget; Koyama, K.; Zhao, Gong-Bo; Li, Baojiu

doi:10.1088/1475-7516/2014/07/058

Cited by 72 publications

(94 citation statements)

References 118 publications

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“…The presence of screening in some gravity theories means that cosmological simulations have become a central tool for calculating testable predictions. Indeed, neglecting screening effects -as done in a linear analysis -can lead to incorrect predictions of the power spectrum of density perturbations over a range of scales that will soon be observable with forthcoming surveys such as Euclid [200]. Furthermore, screening must be taken into account when making predictions for discrete objects such as galaxies or galaxy clusters.…”

Section: Gravity In Cosmologymentioning

confidence: 99%

BeyondΛCDM: Problems, solutions, and the road ahead

Bull

Akrami

Adamek

et al. 2016

Physics of the Dark Universe

459

210

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Despite its continued observational successes, there is a persistent (and growing) interest in extending cosmology beyond the standard model, ΛCDM. This is motivated by a range of apparently serious theoretical issues, involving such questions as the cosmological constant problem, the particle nature of dark matter, the validity of general relativity on large scales, the existence of anomalies in the CMB and on small scales, and the predictivity and testability of the inflationary paradigm. In this paper, we summarize the current status of ΛCDM as a physical theory, and review investigations into possible alternatives along a number of different lines, with a particular focus on highlighting the most promising directions. While the fundamental problems are proving reluctant to yield, the study of alternative cosmologies has led to considerable progress, with much more to come if hopes about forthcoming high-precision observations and new theoretical ideas are fulfilled.Keywords: cosmology -dark energy -cosmological constant problem -modified gravitydark matter -early universe Cosmology has been both blessed and cursed by the establishment of a standard model: ΛCDM. On the one hand, the model has turned out to be extremely predictive, explanatory, and observationally robust, providing us with a substantial understanding of the formation of large-scale structure, the state of the early Universe, and the cosmic abundance of different types of matter and energy. It has also survived an impressive battery of precision observational tests -anomalies are few and far between, and their significance is contentious where they do arise -and its predictions are continually being vindicated through the discovery of new effects (B-mode polarization [1] and lensing [2,3] of the cosmic microwave background (CMB), and the kinetic Sunyaev-Zel'dovich effect [4] being some recent examples). These are the hallmarks of a good and valuable physical theory.On the other hand, the model suffers from profound theoretical difficulties. The two largest contributions to the energy content at late times -cold dark matter (CDM) and the cosmological constant (Λ) -have entirely mysterious physical origins. CDM has so far evaded direct detection by laboratory experiments, and so the particle field responsible for it -presumably a manifestation of "beyond the standard model" particle physics -is unknown. Curious discrepancies also appear to exist between the predicted clustering properties of CDM on small scales and observations. The cosmological constant is even more puzzling, giving rise to quite simply the biggest problem in all of fundamental physics: the question of why Λ appears to take such an unnatural value [5,6,7]. Inflation, the theory of the very early Universe, has also been criticized for being fine-tuned and under-predictive [8], and appears to leave many problems either unsolved or fundamentally unresolvable. These problems are indicative of a crisis.From January 14th-17th 2015, we held a conference in Oslo, Norway to surve...

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Section: Gravity In Cosmologymentioning

confidence: 99%

BeyondΛCDM: Problems, solutions, and the road ahead

Bull

Akrami

Adamek

et al. 2016

Physics of the Dark Universe

459

210

View full text Add to dashboard Cite

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“…The reasons are twofold. First, as shown in [39] the Chameleon mechanism induces a mass dependent screening effect which leads to high mass clusters being screened and low mass clusters being increasingly unscreened. Relative to their high mass counterparts, less screened low mass clusters will exhibit higher escape velocity edges, resulting in a reduced potential ratio compared to expectations from The z = 0 gravitational potential ratio between high and low mass bins of synthetic galaxy clusters for the GR (black), the FR5 (left) parametrization of f (R) gravity (green), and the FR6 (right) parametrization (red).…”

Section: Probing Gravitymentioning

confidence: 99%

Probing theories of gravity with phase space-inferred potentials of galaxy clusters

et al. 2016

Self Cite

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Modified theories of gravity provide us with a unique opportunity to generate innovative tests of gravity. In Chameleon f (R) gravity, the gravitational potential differs from the weak-field limit of general relativity (GR) in a mass dependent way. We develop a probe of gravity which compares high mass clusters, where Chameleon effects are weak, to low mass clusters, where the effects can be strong. We utilize the escape velocity edges in the radius/velocity phase space to infer the gravitational potential profiles on scales of 0.3 -1 virial radii. We show that the escape edges of low mass clusters are enhanced compared to GR, where the magnitude of the difference depends on the background field value |fR0|. We validate our probe using N-body simulations and simulated light cone galaxy data. For a DESI (Dark Energy Spectroscopic Instrument) Bright Galaxy Sample, including observational systematics, projection effects, and cosmic variance, our test can differentiate between GR and Chameleon f (R) gravity models, |fR0| = 4 × 10 −6 (2 × 10 −6 ) at > 5σ (> 2σ), more than an order of magnitude better than current cluster-scale constraints.

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“…on regions of large density or deep potentials [3]. Examples include fðRÞ models with the chameleon mechanism [4][5][6][7][8][9], braneworld models which display the Vainshtein mechanism [10][11][12], and the symmetron model with a symmetry breaking of the scalar potential [13][14][15][16]. Most viable models of cosmic acceleration via modified gravity are nearly indistinguishable at the background level and may be quite degenerate, even when considering linear perturbation effects.…”

Section: Introductionmentioning

confidence: 99%

Modeling void abundance in modified gravity

et al. 2017

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Reprinted with permission from the American Physical Society: Physical Review D, 95, 024018 c (2017) by the American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modied, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society.Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. We use a spherical model and an extended excursion set formalism with drifting diffusive barriers to predict the abundance of cosmic voids in the context of general relativity as well as fðRÞ and symmetron models of modified gravity. We detect spherical voids from a suite of N-body simulations of these gravity theories and compare the measured void abundance to theory predictions. We find that our model correctly describes the abundance of both dark matter and galaxy voids, providing a better fit than previous proposals in the literature based on static barriers. We use the simulation abundance results to fit for the abundance model free parameters as a function of modified gravity parameters, and show that counts of dark matter voids can provide interesting constraints on modified gravity. For galaxy voids, more closely related to optical observations, we find that constraining modified gravity from void abundance alone may be significantly more challenging. In the context of current and upcoming galaxy surveys, the combination of void and halo statistics including their abundances, profiles and correlations should be effective in distinguishing modified gravity models that display different screening mechanisms.

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The Vainshtein mechanism in the cosmic web

Cited by 72 publications

References 118 publications

BeyondΛCDM: Problems, solutions, and the road ahead

BeyondΛCDM: Problems, solutions, and the road ahead

Probing theories of gravity with phase space-inferred potentials of galaxy clusters

Modeling void abundance in modified gravity

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