Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: N-body Simulations of $\gamma$ Gravity   We have investigated structure formation in the $\gamma$ gravity $f(R)$ model
with {\it N}-body simulations. The $\gamma$ gravity model is a proposal which,
unlike other viable $f(R)$ models, not only changes the gravitational dynamics,
but can in principle also have signatures at the background level that are
different from those obtained in $\Lambda$CDM (Cosmological constant, Cold Dark
Matter). The aim of this paper is to study the nonlinear regime of the model in
the case where, at late times, the background differs from $\Lambda$CDM. We
quantify the signatures produced on the power spectrum, the halo mass function,
and the density and velocity profiles. To appreciate the features of the model,
we have compared it to $\Lambda$CDM and the Hu-Sawicki $f(R)$ models. For the
considered set of parameters we find that the screening mechanism is
ineffective, which gives rise to deviations in the halo mass function that
disagree with observations. This does not rule out the model per se, but
requires choices of parameters such that $|f_{R0}|$ is much smaller, which
would imply that its cosmic expansion history cannot be distinguished from
$\Lambda$CDM at the background level.

4
The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int