Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cosmic Acceleration as an Optical Illusion   We consider light propagation in an inhomogeneous irrotational dust universe
with vanishing cosmological constant, with initial conditions as in standard
linear perturbation theory. A non-perturbative approach to the dynamics of such
a universe is combined with a distance formula based on the Sachs optical
equations. Then a numerical study implies a redshift-distance relation that
roughly agrees with observations. Interpreted in the standard homogeneous
setup, our results would appear to imply the currently accepted values for the
Hubble rate and the deceleration parameter; furthermore there is consistency
with density perturbations at last scattering. The determination of these three
quantities relies only on a single parameter related to a cutoff scale.
Discrepancies with the existing literature are related to subtleties of higher
order perturbation theory which make both the reliability of the present
approach and the magnitude of perturbative effects beyond second order hard to
assess.

17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg