Sherrington-Kirkpatric自旋玻璃模型的非平衡态性质

通过动力学蒙特卡罗模拟对Sherrington-Kirkpatric （SK）自旋玻璃模型进行研究. 结果表明，弱场下自旋玻璃的磁化率在转变点非常陡峭，而比热容则呈现比较宽的转变. 同时，也成功地模拟了自旋玻璃体的年龄效应和记忆效应. 通过模拟发现，不同的弛豫时间对系统的能量影响很大，这直接导致了年龄效应和记忆效应；各向同性的SK模型不能给出实验中的交换偏移现象. 关键词： 自旋玻璃 记忆效应 年龄效应 磁化率

Nonequilibrium properties of Sherrington-Kirkpatric spin glass model

Using Sherrington-Kirkpatric （SK） model we investigated the nonequilibrum properties of spin glass by dynamical Monte Carlo simulation. Our results revealed that the susceptibility in the weak field shows a cusp near the glass transition, while the specific heat shows a more broad transition. The aging and zero-field colding memory effect is also reproduced in our simulation, and the phenomena can be explained by energy relaxation. Our simulation also reveals that homogeneous SK model can not reproduce the exchange bias effect observed in the experiment.