Quantum Phase Transitions in Spin Star Configuration

作     者：DENG Hong-Liang FANG Xi-Ming 

作者机构：Key Laboratory of Quantum Structure and Quantum Control of Ministry of Education and Department of PhysicsHunan Normal University Changsha 410081 China 

出 版 物：《Communications in Theoretical Physics》 (理论物理通讯（英文版）)

年 卷 期：2008年第49卷第5期

页      面：1353-1356页

核心收录：

学科分类：07[理学] 070201[理学-理论物理] 0702[理学-物理学] 

基　　金：The project supported by National Basic Research Program of China under Grant No.2007CB925204 

主　　题：quantum phase transitions ground state 

摘      要：We consider a generalized spin star configuration that can be solved exactly, with the central spin-1/2 system embedded in an outer ring of N spin-1/2 particles （denoted as spin bath）. In this model, we consider a modified version of the spin star model, by taking into account, besides the interaction of the central spin with the bath, the interactions between the spins of the bath as well. The general expressions of the eigenstates as well as the eigenvalues of the model are derived with the use of the symmetries of system. We then investigate the properties of the ground quantum phase transitions in some limiting cases in the model and show that the occurrence of quantum phase transitions and the desired ground states can be obtained by varying the external control parameters.