Entanglement structure of the two-channel Kondo model
Entanglement structure of the two-channel Kondo model
复制标题
DOI：
10.1103/physrevb.93.081106
复制
发表时间：
2016-02-18
影响因子：
3.7
通讯作者：
Le Hur, Karyn
中科院分区：
文献类型：
--
作者：
Alkurtass, Bedoor;Bayat, Abolfazl;Le Hur, Karyn
在双通道近藤模型中，竞争屏蔽单个杂质自旋的两个电子通道有望产生具有非平凡纠缠结构的基态。我们利用双通道Kondo模型的自旋链表示，利用密度矩阵重整化群方法，研究了基态块熵、负性、纠缠和施密特能隙。在两个通道存在对称耦合的情况下，我们证实了场论预言的紫外界和红外界之间的边界熵差ln(g(UV)/g(IR))=ln(2)/2以及引入的ln(X)/x杂质对块熵的修正。结果表明，S IMP中的杂质纠缠与特征长度Xi(2Ck)成比例关系。我们发现，施密特带隙和杂质与其中一个通道的纠缠--用负性测量--都忠实地作为杂质量子相变的序参数，呈现为通道不对称性的函数，允许显式地确定临界指数，nU近似为2，β近似为0.2。值得注意的是，我们发现只有在临界通道对称点附近才会出现三体纠缠。
Two electronic channels competing to screen a single impurity spin, as in the two-channel Kondo model, are expected to generate a ground state with a nontrivial entanglement structure. We exploit a spin-chain representation of the two-channel Kondo model to probe the ground-state block entropy, negativity, tangle, and Schmidt gap, using a density matrix renormalization group approach. In the presence of symmetric coupling to the two channels, we confirm field-theory predictions for the boundary entropy difference ln(g(UV)/g(IR)) = ln(2)/2 between the ultraviolet and infrared limits and the leading ln(x)/x impurity correction to the block entropy. The impurity entanglement S-imp is shown to scale with the characteristic length xi(2CK). We show that both the Schmidt gap and the entanglement of the impurity with one of the channels-as measured by the negativity-faithfully serve as order parameters for the impurity quantum phase transition appearing as a function of channel asymmetry, allowing for explicit determination of critical exponents, nu approximate to 2 and beta approximate to 0.2. Remarkably, we find the emergence of tripartite entanglement only in the vicinity of the critical channel-symmetric point.