Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Future Island Universes in a Background Universe Accelerated by
  Cosmological Constant and by Quintessence   We study bound object formation in a background universe accelerated by
cosmological constant and by quintessence. If the acceleration lasts forever,
due to the existence of event horizon, one would have naively expected the
universe to approach a state of cold death. However, we find that many local
regions in the universe can in fact be protected by their own gravity to form
mini-universes, provided that their present matter densities exceed some
critical value. In the case with cosmological constant ($\Lambda$CDM cosmology)
the condition of forming mini-universe is that the ratio of present density
parameters $\Omega_{i}^0/\Omega_\Lambda$ ought to be larger than a critical
value 3.63. Such mini-universes typically weigh less than $2\times 10^{14}$
solar masses, with the lighter ones having tight and compact configurations. In
the case with quintessence, the final ratio $\Omega_i/\Omega_q$ of a
mini-universe is found to be always larger than $w_q^2-w_q$, where $w_q$ is the
equation of state parameter.

2
The categories of this paper are: math
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph