无序非谐振链中量子热传输特性的研究

Influence of the heat bath on the heat conductivity in disordered anharmonic chain

运用发展的Ford-Kac-Mazur方法对一维无序非谐振链的热传输特性进行了研究，从中得到了热导k率与系统大小（N）之间满足关系式k-Na。并且分别在自由边界条件及固定边界条件下得到k与N之间满足k～N^1/2。和k～N^-1/2的结论，由此得出动量是决定反常热传导的关键因素。同时，通过对不同温度下对线性及非线性系统热导率的比较发现二者之间存在较大的差别。

We study heat conduction in a one-dimensional disordered anharmonic chain with arbitrary heat bath by using extended Ford, Kac and Mazur （FKM） formation, which satisfy the fluctua- tion-dissipation theorem. A simple formal expression for the heat conductivity k is obtained, from which the asymptotic system-size （N） dependence is extracted. It shows to--N% As a special case we give the expression that k-N^1/2 for free boundaries, and k-N^-1/2 for fixed ones. Thus we can get following conclusion, the momentum conversation is a key factor to determine the anomalous heat conduction. Comparing the heat conductivity in both linear system and the nonlinear system with different temperatures, shows that a large difference between these two systems.