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基于Lindblad和Redfield方程的自旋链平衡性质研究

发表时间:2013-08-15  浏览量:1236  下载量:346
全部作者: 黄洁,刘会平,徐震,钟鸣
作者单位: 南京师范大学物理科学与技术学院
摘 要: 导出自旋链下Lindblad方程和Redfield方程的具体形式,并数值计算一维均匀量子Ising链在左右两端热源温度相同情况下的平均磁矩和最近邻关联函数。通过与解析结果比较发现:当系统内部处于弱耦合情况下,即外场h远大于自旋间交换相互作用J时,用2种方程计算出的结果均与解析结果非常接近;而在系统内部耦合强度较大的情况下,即h接近于J时,2种方程计算的结果与解析结果有一定的差别,因为这2个方程都由动力学方程通过不同近似条件得出。温度越高,比较Redfield与Lindblad的计算结果,前者更接近解析结果。
关 键 词: 统计物理学;自旋模型;Lindblad方程;Redfield方程;弱耦合;强耦合
Title: Study on the equilibrium properties in spin chain by Lindblad and Redfield equation
Author: HUANG Jie, LIU Huiping, XU Zhen, ZHONG Ming
Organization: School of Physics and Technology, Nanjing Normal University
Abstract: In this paper, we derived the concrete forms of Lindblad equation and Redfield equation in the spin chain. Then the average magnetic moment and nearest neighbor correlation functions of one-dimensional homogeneous quantum Ising chain whose two ends are connected with baths with the same temperature were numerically simulated. By contrast of analytical results, we found that when the system internal was in weak coupling which the external field h was greater than the exchange interaction between the spin J, the calculated results of two equations above were both very closed to the analytical result. However, when the system internal was in tight coupling which h was closed to J, both of results calculated by two equations above had a gap. It was proved that the two equations were derived through different approximation conditions of kinetic equation. Moreover, when the temperature was higher, compared with the Lindblad equation, the Redfield equation was more close to the analytical results.
Key words: statistic physics; spin model; Lindblad equation; Redfield equation; weak coupling; tight coupling
发表期数: 2013年8月第15期
引用格式: 黄洁,刘会平,徐震,等. 基于Lindblad和Redfield方程的自旋链平衡性质研究[J]. 中国科技论文在线精品论文,2013,6(15):1411-1418.
 
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