Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Relativistic effects and primordial non-Gaussianity in the matter
  density fluctuation   We present the third-order analytic solution of the matter density
fluctuation in the proper-time hypersurface of nonrelativistic matter flows by
solving the nonlinear general relativistic equations. The proper-time
hypersurface provides a coordinate system that a local observer can set up
without knowledge beyond its neighborhood, along with physical connections to
the local Newtonian descriptions in the relativistic context. The initial
condition of our analytic solution is set up by the curvature perturbation in
the comoving gauge, clarifying its impact on the nonlinear evolution. We
compute the effective non-Gaussian parameters due to the nonlinearity in the
relativistic equations. With proper coordinate rescaling, we show that the
equivalence principle is respected and the relativistic effect vanishes in the
large-scale limit.

27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
26
The categories of this paper are: bayes-an
16
The categories of this paper are: stat
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an