Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Coupled cluster treatment of one quasi-one-dimensional coupled spin
  triangles   By using the coupled cluster method (CCM) and the numerical exact
diagonalization (ED) method, we investigated the properties of the one
quasi-one-dimensional coupled spin triangles. The results of ED disclose that
the system is in the exact tetramer-dimer (TD) state if a<ac1 . We prove that
the exact TD state can be formed by using CCM in that parameter region. It is
more interesting to find that the exact spin gap in the TD state can also be
obtained via CCM. At the critical point ac1, a first order transition occurs
and the ground state of the system evolves from the TD state to the
ferromagnetic long range order state. In the parameter region a>ac1, we find
that CCM results for some physical quantities, such as the ground state energy,
the magnetization and the antiferromagnetic gap are in excellent agreement with
the results obtained by ED. Thus, CCM can be used to accurately analyze the
properties of the quasi-one-dimensional coupled spin triangles in the whole
parameter region. We believe that it can also be applied to investigating the
properties of other quasi-one spin systems reliably.

3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
16
The categories of this paper are: stat
8
The categories of this paper are: hep-ex
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc