Department of Physics, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait.
Wigner Research Centre, Institute for Solid State Physics and Optics, H-1525 Budapest, P.O. Box 49, Hungary.
Phys Rev E. 2017 Jan;95(1-1):012105. doi: 10.1103/PhysRevE.95.012105. Epub 2017 Jan 4.
The entanglement entropy 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 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 S across the transition point. According to numerical, density matrix renormalization group results at the first-order quantum phase transition point S shows a jump, which is expected to vanish for Q→4^{+}. This jump is calculated in leading order as ΔS=lnQ[1-4/Q-2/(QlnQ)+O(1/Q^{2})].
纠缠熵 S 是多体量子系统基态量子关联的一个指标。在一维的二级量子相变点，S 通常具有对数奇点。在这里，我们考虑具有一级量子相变的量子自旋链，原型是 Q>4 的 Q 态量子 Potts 链，并在相变点处计算 S。根据数值，密度矩阵重整化群的结果，在一级量子相变点，S 表现出一个跃变，预计当 Q→4^{+}时，它会消失。这个跃变可以在领头阶上计算为 ΔS=lnQ[1-4/Q-2/(QlnQ)+O(1/Q^{2})]。
