Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Analysis of quantum phase transition in some different Curie-Weiss
  models: a unified approach   A unified approach to the analysis of quantum phase transitions in some
different Curie-Weiss models is proposed such that they are treated and
analyzed under the same general scheme. This approach takes three steps:
balancing the quantum Hamiltonian by an appropriate factor, rewriting the
Hamiltonian in terms of $SU(2)$ operators only, and obtention of a classical
Hamiltonian. $SU(2)$ operators are obtained from creation and annihilation
operators as linear combinations in the case of fermions and as an inverse
Holstein-Primakoff transformation in the case of bosons. This scheme is
successfully applied to Lipkin, pairing, Jaynes-Cummings, bilayer, and
Heisenberg models.

32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin