Modifying Gravity at Low Redshift

Abstract

We consider the growth of cosmological perturbations in modified gravity models where a scalar field mediates a non-universal Yukawa force between different matter species. The growth of the density contrast is altered for scales below the Compton wave-length of the scalar field. As the universe expands, the Compton wave-length varies in time in such a way that scales which were outside the range of the scalar field force may feel it at a lower redshift. In this case, both the exponent $\gamma$ measuring the growth of Cold Dark Matter perturbations and the slip function representing the ratio of the two Newtonian potentials $\psi$ and $\varphi$ may differ from their values in General Relativity at low redshift.

27 pages, 5 figures; revised version, to appear in JCAP.

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Cited by in corpus (12)

• The Dilaton and Modified Gravity
• Matter perturbations in Galileon cosmology
• Density perturbations in general modified gravitational theories
• Time dependent couplings in the dark sector: from background evolution to nonlinear structure formation
• Observational signatures of modified gravity on ultra-large scales
• Linear Growth of Structure in the Symmetron Model
• Multiple Dark Matter as a self-regulating mechanism for dark sector interactions
• Modified Gravity: the CMB, Weak Lensing and General Parameterisations
• Cosmological Large-scale Structures beyond Linear Theory in Modified Gravity
• Parameterizing scalar-tensor theories for cosmological probes
• Modified Gravity and the CMB
• Theory of interacting vector dark energy and fluid