Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin-gap study of the spin-$\frac{1}{2}$ $J_{1}$--$J_{2}$ model on the
  triangular lattice   We use the coupled cluster method implemented at high orders of approximation
to study the spin-$\frac{1}{2}$ $J_{1}$--$J_{2}$ model on the triangular
lattice with Heisenberg interactions between nearest-neighbour and
next-nearest-neighbour pairs of spins, with coupling strengths $J_{1}>0$ and
$J_{2} \equiv \kappa J_{1} >0$, respectively. In the window $0 \leq \kappa \leq
1$ we find that the 3-sublattice 120$^{\circ}$ N\'{e}el-ordered and
2-sublattice 180$^{\circ}$ stripe-ordered antiferromagnetic states form the
stable ground-state phases in the regions $\kappa < \kappa^{c}_{1} = 0.060(10)$
and $\kappa > \kappa^{c}_{2} = 0.165(5)$, respectively. The spin-triplet gap is
found to vanish over essentially the entire region $\kappa^{c}_{1} < \kappa <
\kappa^{c}_{2}$ of the intermediate phase.

26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat