Abstract
The formation of cosmic structures is an important diagnostic for both the dynamics of the cosmological model and the underlying theory of gravity. At the linear level of these structures, certain degeneracies remain between different cosmological models and alternative gravity theories. It is thus indispensable to study the non-linear, late-time evolution of cosmic structures to try and disentangle their fundamental properties caused by the cosmological model or gravity theory itself. Conventionally, non-linear cosmic structure formation is studied by means of computationally expensive numerical simulations. Since these inevitably suffer from shot noise and are too time consuming to systematically scrutinize large parameter spaces of cosmological models or fundamental theories, analytical methods are needed to overcome the limitations of numerical simulations.Recently, a new analytic approach to non-linear cosmic structure formation has been proposed based on kinetic field theory for classical particle ensembles. Within this theory, a closed, analytic, non-perturbative and parameter-free equation could be derived for the non-linear power spectrum of cosmic density perturbations which agrees very well with numerically simulated results to wave numbers k≲10hMpc−1 at redshift z=0. In this Letter, we study for the first time the implications of alternative gravity theories for non-linear cosmic structure formation applying this promising new analytic framework. As an illustrative example, we consider vector-tensor theories, which support very interesting isotropic cosmological solutions.
Highlights
Cosmic structure formation is an indispensable process for probing into the true nature of gravity
Since these inevitably suffer from shot noise and are too time consuming to systematically scrutinize large parameter spaces of cosmological models or fundamental theories, analytical methods are needed to overcome the limitations of numerical simulations
In this Letter, we study for the first time the implications of alternative gravity theories for non-linear cosmic structure formation applying this promising new analytic framework
Summary
Cosmic structure formation is an indispensable process for probing into the true nature of gravity. On small scales and at late cosmic times, their approximate description by linearized equations breaks down because the density fluctuations become highly non-linear, and the hydrodynamical equations fail because they cannot account for multivalued velocity fields. This leads to the notorious shell-crossing problem. Non-linear cosmic structure formation is studied using highly elaborate N-body simulations They decompose the cosmic density field into pseudo-particles with a mass set by the spatial resolution of the simulation. Testing alternative theories of gravity on cosmological scales requires a thorough comparison of late-time and non-linear cosmic structures to the standard evolution in the framework of general relativity [4,5]. Note that the notorious shell- or stream-crossing problem does not even occur in this approach since Hamiltonian trajectories cannot cross in phase space
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
