Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Entanglement entropy of the $Q \ge 4$ quantum Potts chain   The entanglement entropy, ${\cal S}$, is an indicator of quantum correlations
in the ground state of a many body quantum system. At a second-order quantum
phase-transition point in one dimension ${\cal S}$ generally has a logarithmic
singularity. Here we consider quantum spin chains with a first-order quantum
phase transition, the prototype being the $Q$-state quantum Potts chain for
$Q>4$ and calculate ${\cal S}$ across the transition point. According to
numerical, density matrix renormalization group results at the first-order
quantum phase transition point ${\cal S}$ shows a jump, which is expected to
vanish for $Q \to 4^+$. This jump is calculated in leading order as $\Delta
{\cal S}=\ln Q[1-4/Q-2/(Q \ln Q)+{\cal O}(1/Q^2)]$.

30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
2
The categories of this paper are: math
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph