Modified-source gravity and cosmological structure formation

By S. Carroll, I. Sawicki, A. Silvestri, M. Trodden. 2006

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One way to account for the acceleration of the universe is to modify general relativity, rather than introducing dark energy. Typically, such modifications introduce new degrees of freedom. It is interesting to consider models with no new degrees of freedom, but with a modified dependence on the conventional energy-momentum tensor; the Palatini formulation of f(R) theories is one example. Such theories offer an interesting testing ground for investigations of cosmological modified gravity. In this paper we study the evolution of structure in these ‘modified-source gravity’ (MSG) theories. In the linear regime, density perturbations exhibit scale dependent runaway growth at late times and, in particular, a mode of a given wavenumber goes nonlinear at a higher redshift than in the standard lambda-cold dark matter (ΛCDM) model. We discuss the implications of this behaviour and why there are reasons to expect that the growth will be cut off in the nonlinear regime. Assuming that this holds in a full nonlinear analysis, we briefly describe how upcoming measurements may probe the differences between the modified theory and the standard ΛCDM model.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/7a0046974eb19f4ea9d5c4306f690b4f6da99801

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Citations in the corpus

Approaches to understanding cosmic acceleration (2009, background): “Since such models are a little outside the scope of this paper, we will not comment on them further, other than to point out that linear perturbation theory seems to show a possible conflict with observations of the formation of structure [129].”
Probing the theory of gravity with gravitational lensing of gravitational waves and galaxy surveys (2019, background): “(9) (Carroll et al. 2006; Bean et al. 2007; Hu & Sawicki 2007; Schmidt 2008; Silvestri et al. 2013; Baker et al. 2015; Lombriser & Taylor 2016; Lombriser & Lima 2017; Saltas et al. 2014; Baker & Bull 2015; Slosar et al. 2019) such as (i) g(k, z) 6= 0, (ii) the modified Poisson Equation, (iii)…”
f(R) Theories Of Gravity (2008, methodology): “Cosmological density perturbations in the Palatini formalism have been studied in (Amarzguioui et al., 2006; Carroll et al., 2006; Koivisto, 2006b, 2007; Koivisto and Kurki-Suonio, 2006; Lee, 2007, 2008; Li et al., 2007b; Uddin et al., 2007).”
f(R) Theories (2010, background): “The existence of the latter phase gives rise to the modification to the matter power spectrum [146, 74, 544, 526, 251] (see also [597, 493, 494, 94, 446, 278, 435] for related works).”
Cosmology and Fundamental Physics with the Euclid Satellite (2012, background): “This is required for consistency with local gravity tests [431, 918, 471, 900], for the presence of the matter-dominated epoch [58, 51], and for the stability of cosmological perturbations [286, 1112, 148, 475].”
Modified Gravity and Cosmology (2011, methodology): “For studies of weak field gravity in the Palatini formalism the reader is referred to [92, 429, 881, 999, 30, 1000, 1163, 1001, 1078, 224, 665, 31, 1077], and for cosmology to [1251, 509, 883, 28, 882, 884, 29, 1162, 1164, 724, 34, 727, 258, 793, 1232, 725, 781, 782, 497].”