Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A possible trial beyond the conventional random phase approximation for
  the su(2)-Lipkin model including the case of non-closed shell system   Concerning the su(2)-Lipkin model, the calculation of the excitation energy
to the 1st excited-state gives rise to the following fact: The two results
based on the exact treatment and the conventional random phase approximation
(RPA) are in unexpected disagreement. In order to remove this discrepancy, the
conventional RPA is renewed. With the aim of this renewal, the terms, which
cannot be dealt with in the conventional one, are estimated. The basic
framework of this new form is not reorganized from that of the conventional
one. In addition, the su(2)-Lipkin model itself is also modified so as to be
applicable to the case with non-closed shell system. To this modification, one
more su(2)-algebra, which has been already proposed by the present authors, is
applied. Through the use of this algebra, the su(2)-Lipkin model is applicable
to the case with any total fermion number permitted in the model.

17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci