Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mirage Cosmology on Unstable D3-Brane Universe   We study the geodesic motion of an unstable brane moving in a higher
dimensional bulk spacetime. The tachyon which is coupled to a U(1) gauge field
induces a non-trivial cosmological evolution. Interestingly enough, this system
exhibits a much smoother initial cosmological singularity in comparison with
former works.

14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
1
The categories of this paper are: cs
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci