Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dark Matter and Dark Energy: A Physicist's Perspective   For physicists, recent developments in astrophysics and cosmology present
exciting challenges. We are conducting "experiments" in energy regimes some of
which will be probed by accelerators in the near future, and others which are
inevitably the subject of more speculative theoretical investigations. Dark
matter is an area where we have hope of making discoveries both with
accelerator experiments and dedicated searches. Inflation and dark energy lie
in regimes where presently our only hope for a fundamental understanding lies
in string theory.

9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con