Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: D-branes and Cosmology   D-branes, topological defects in string theory on which string endpoints can
live, may give new insight into the understanding of the cosmological evolution
of the Universe at early epochs. We analyze the dynamics of D-branes in curved
backgrounds and discuss the parameter space of M-theory as a function of the
coupling constant and of the curvature of the Universe. We show that D-branes
may be efficiently produced by gravitational effects. Furthermore, in curved
spacetimes the transverse fluctuations of the D-branes develop a tachyonic mode
and when the fluctuations grow larger than the horizon the branes become
tensionless and break up. This signals a transition to a new regime. We discuss
the implications of our findings for the singularity problem present in string
cosmology, suggesting the existence of a limiting value for the curvature which
is in agreement with the value suggested by the cosmological version of the
holography principle. We also comment on possible implications for the
so-called brane world scenario, where the Standard Model gauge and matter
fields live inside some branes while gravitons live in the bulk.

21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys