Quantum Fidelity and Thermal Phase Transitions in a Two-Dimensional Spin System  

作　　者：WANG Bo HUANG Hai-Lin SUN Zhao-Yu KOU Su-Peng 王波;黄海林;孙照宇;寇谡鹏(Department of Physics,Beijing Normal University,Beijing 100875;School of Electrical and Electronic Engineering,Wuhan Polytechnic University,Wuhan 430000)

机构地区：[1]Department of Physics,Beijing Normal University,Beijing 100875 [2]School of Electrical and Electronic Engineering,Wuhan Polytechnic University,Wuhan 430000

出　　处：《Chinese Physics Letters》2012年第12期9-12,共4页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(No 11204223);the China Postdoctoral Science Foundation(No 2012M510342);the Talent Scientific Research Foundation of WHPU(Nos 2012RZ09,2011RZ15).

摘　　要：We investigate the ability of quantum fidelity in detecting the classical phase transitions(CPTs)in a two-dimensional Heisenberg-Ising mixed spin model,which has a very rich phase diagram and is exactly soluble.For a two-site subsystem of the model,the reduced fidelity(including the operator fidelity and the fidelity susceptibility)at finite temperatures is calculated,and it is found that an extreme value presents at the critical temperature,thus shows a signal for the CPTs.In some parameter region,the signal becomes blurred.We propose to use the"normalized fidelity susceptibility"to solve this problem.

关 键 词：SUSCEPTIBILITY Transition EXTREME 

分 类 号：O41[理学—理论物理]