Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Structure formation and the origin of dark energy   Cosmological constant a.k.a. dark energy problem is considered to be one
major challenge in modern cosmology. Here we present a model where large scale
structure formation causes spatially-flat FRW universe to fragment into
numerous `FRW islands' surrounded by vacuum. We show that this mechanism can
explain the origin of dark energy as well as the late time cosmic acceleration.
This explanation of dark energy does not require any exotic matter source nor
an extremely fine-tuned cosmological constant. This explanation is given within
classical general relativity and relies on the fact that our universe has been
undergoing structure formation since its recent past.

36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con
4
The categories of this paper are: cond-mat
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio