Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Solving the Coincidence Problem: Tracking Oscillating Energy   Recent cosmological observations strongly suggest that the universe is
dominated by an unknown form of energy with negative pressure. Why is this dark
energy density of order the critical density today? We propose that the dark
energy has periodically dominated in the past so that its preponderance today
is natural. We illustrate this paradigm with a model potential and show that
its predictions are consistent with all observations.

8
The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol