Effects of Bond Alternation on the Ground-State Phase Diagram of One-Dimensional XXZ Model  

作　　者：强凌 刘光华 田光善 

机构地区：[1]School of Physics,Peking University [2]Department of Physics,Tianjin Polytechnic University

出　　处：《Communications in Theoretical Physics》2013年第8期240-246,共7页理论物理通讯（英文版）

基　　金：Supported by the National Science Foundation of China under Grant No.11074004;Supported by the National Basic Research Program of China under Grant No.2009CB939901

摘　　要：The ground-state properties and quantum phase transitions （ QPTs） of the one-dimensional bond-Mternative XXZ model are investigated by the infinite time-evolving block decimation （iTEBD） method. The bond-alternative effects on its ground-state phase diagram are discussed in detail. Once the bond alternation is taken into account, the antiferromagnetic phase （△ 〉 1） will be destroyed at a given critical point and change into a disordered phase without nonlocal string order. The QPT is shown to be second-order, and the whole phase diagram is provided. For the ferromagnetic phase region （△ 〈 --1）, the critical point re always equals 1 （independent of △）, and the QPT for this case is shown to be first-order. The dimerized Heisenberg model is also discussed, and two disordered phases can be distinguished by with or without nonlocal string orders. Both the bipartite entanglement and the fidelity per site, as two kinds of model-independent measures, are capable of describing all the QPTs in such a quantum model.

关 键 词：matrix product state quantum entanglement quantum phase transitions 

分 类 号：O431.2[机械工程—光学工程]