Guillermo Ballesteros, Lukas Hollenstein, Rajeev Kumar Jain, Martin Kunz
We propose a completely nonlinear framework to construct consistency
relations for testing generic cosmological scenarios using the evolution of
large scale structure. It is based on the covariant approach in combination
with a frame that is purely given by the metric, the normal frame. As an
example, we apply this framework to the LCDM model, extending the usual first
order conditions on the metric potentials to second order. We argue that
working in the normal frame is not only a practical choice but one that closely
resembles our actual situation as observers. In this frame, effective pressures
and anisotropic stresses appear at second order in perturbation theory, even
for dust. We quantify this effect and compare it, for illustration, with the
pressure of a generic clustering dark energy fluid and the anisotropic stress
in the DGP model. Besides, we also discuss the effect of a mismatch of the
potentials on the determination of galaxy bias.
View original:
http://arxiv.org/abs/1112.4837
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