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arXiv · 1511.05962

Searching for scalar gravitational interactions in current and future cosmological data

Alireza Hojjati·Aaron Plahn·Alex Zucca·Levon Pogosian·Philippe Brax·Anne-Christine Davis·Gong-Bo Zhao
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Abstract

Modified gravity theories often contain a scalar field of gravitational strength which interacts with matter. We examine constraints on the range and the coupling strength of a scalar gravitational degree of freedom using a subset of current data that can be safely analyzed within the linear perturbation theory. Using a model-independent implementation of scalar-tensor theories in MGCAMB in terms of two functions of the scale factor describing the mass and the coupling of the scalar degree of freedom, we derive constraints on the $f(R)$, generalized chameleon, Symmetron and Dilaton models. Since most of the large scale structure data available today is from relatively low redshifts, only a limited range of observed scales is in the linear regime, leading to relatively weak constraints. We then perform a forecast for a future large scale structure survey, such as Large Synoptic Survey Telescope (LSST), which will map a significant volume at higher redshifts, and show that it will produce much stronger constraints on scalar interactions in specific models. We also perform a principal component analysis and find that future surveys should be able to provide tight constraints on several eigenmodes of the scalar mass evolution.

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Alireza Hojjati, Aaron Plahn, Alex Zucca, Levon Pogosian, Philippe Brax, Anne-Christine Davis, Gong-Bo Zhao. 2015-11-18. Searching for scalar gravitational interactions in current and future cosmological data. https://doi.org/10.1103/physrevd.93.043531

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