Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bose-Einstein Condensation and Many-Body Localization of Rotational
  Excitations of Polar Molecules   We study theoretically the collective dynamics of rotational excitations of
polar molecules loaded into an optical lattice in two dimensions. These
excitations behave as hard-core bosons with a relativistic energy dispersion
arising from the dipolar coupling between molecules. This has interesting
consequences for the collective many-body phases. The rotational excitations
can form a Bose-Einstein condensate at non-zero temperature, manifesting itself
as a divergent $T_2$ coherence time of the rotational transition even in the
presence of inhomogeneous broadening. The dynamical evolution of a dense gas of
rotational excitations shows regimes of non-ergodicity, characteristic of
many-body localization and localization protected quantum order.

37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ