Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Linear sigma model at finite density in the 1/N expansion to
  next-to-leading order   We study relativistic Bose-Einstein condensation at finite density and
temperature using the linear sigma model in the one-particle-irreducible
1/N-expansion. We derive the effective potential to next-to-leading (NLO) order
and show that it can be renormalized in a temperature-independent manner. As a
particular application, we study the thermodynamics of the pion gas in the
chiral limit as well as with explicit symmetry breaking. At nonzero temperature
we solve the NLO gap equation and show that the results describe the
chiral-symmetry-restoring second-order phase transition in agreement with
general universality arguments. However, due to nontrivial regularization
issues, we are not able to extend the NLO analysis to nonzero chemical
potential.

17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin