Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effect of $U_A(1)$ Breaking on Chiral Phase Structure and Pion
  Superfluidity at Finite Isospin Chemical Potential   We investigate the isospin chemical potential effect in the frame of SU(2)
Nambu-Jona-Lasinio model. When the isospin chemical potential is less than the
vacuum pion mass, the phase structure with two chiral phase transition lines
does not happen due to $U_A(1)$ breaking of QCD. When the isospin chemical
potential is larger than the vacuum pion mass, the ground state of the system
is a Bose-Einstein condensate of charged pions.

9
The categories of this paper are: nlin
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
4
The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc