Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum phase transition of the two-dimensional Rydberg atom array in an
  optical cavity   We study the two-dimensional Rydberg atom array in an optical cavity with
help of the meanfield theory and the large-scale quantum Monte Carlo
simulations. The strong dipole-dipole interactions between Rydberg atoms can
make the system exhibit the crystal structure, and the coupling between
two-level atom and cavity photon mode can result in the formation of the
polariton. The interplay between them provides a rich quantum phase diagram
including the Mott, solid-1/2, superradiant and superradiant solid phases. As
the two-order co-existed phase, the superradiant solid phase breaks both
translational and U(1) symmetries. Based on both numerical and analytic
results, we found the region of superradiant solid is much larger than one
dimensional case, so that it can be more easily observed in the experiment.
Finally, we discuss how the energy gap of the Rydberg atom can affect the type
of the quantum phase transition and the number of triple points.

3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph