摘要
文章计算了海森堡J1-J2自旋链的任意两格点间的量子失谐与相对熵纠缠,不仅给出了量子失谐、相对熵纠缠与两格点自旋关联函数的解析关系,而且给出了精确对角化的数值结果。解析结果指出了两格点的量子失谐与纠缠非零的条件,并为用两格点的量子失谐与纠缠探测该模型的相变点提供了理论依据。数值结果表明,在该模型中,量子失谐比纠缠具有较长程的关联,近邻和远距离两格点间的量子失谐在基态时能标度一级相变点J2/J1=0.5,在第一激发态时,除了能标度相变点J2/J1=0.5外,还能标度无穷级相变点J2/J1=0.241 1;而纠缠仅存在最近邻与次近邻两格点间,且只有最近邻两格点的纠缠能标度相变点。
In this paper, we calculated the quantum discord and relative entropy of entanglement of two lattice sites at any distance in Heisenberg J1-J2 spin chain, not only the analytical relationship with spin correlation function, but also the numerical result by exact diagonalization method were received. The analytical result pointed out the condition for nonzero quantum discord and entanglement, and provided theoretical foundation for detecting phase transition point by using quantum discord and entanglement between two lattice sites in this model. The specific numerical result showed that quantum discord has a longer range of correlation than entanglement, and quantum discord of two lattice sites, regardless of near to or far from each other, can scale the first-order phase transition point J2/J1=0. 5 in the groundstate, and in the first excited state can scale not only the first-order phase transition point J2/J1 =0.5, but also the infinite-order phase transition point J2/J1 =0. 2411 in this model. Quite different from quantum discord,entanglement exists only between the nearest-neighbor and the next-neighbor lattice sites, and only entanglement between two nearest-neighbor lattice sites can scale phase transition point.
出处
《量子光学学报》
北大核心
2015年第1期1-8,共8页
Journal of Quantum Optics
基金
国家自然科学基金(10875087)
