Magnetic ordering and slow dynamics of frustrated systems

本文主要对自旋玻璃的磁有序和阻挫磁体的慢动力学进行了理论和数值研究。特别注意的是“手性”，最近的理论和实验兴趣的数量。我们研究了最近提出的“自旋-手征解耦”的特殊行为是否真的发生，以及手征引起的各种非平衡现象，如波动耗散关系的破坏。我们对三维Heisenberg Edward-Anderson模型进行了大尺度Monte Carlo模拟，揭示了有限温度下的手征玻璃化转变和长时间尺度下的自旋手征解耦现象，正如作者所预言的那样.研究还发现，在手性玻璃有序态中出现了一步式的复制对称性破缺现象。在磁场中，这种RSB甚至在磁场中也会引起热力学SQ转变，这一致地解释了正则自旋玻璃在磁场中行为的长期实验难题。通过对自旋玻璃的非平衡模拟，违反涨落耗散定理，确实观察到了这种奇特的RSB图案。

Magnetic ordering and slow dynamics of frustrated magnets have been studied theoretically and numerically mainly for spin glasses. Particular attention was paid to the "chirality", a quantity of recent theoretical and experimental interest. We examined whether the peculiar behavior of the "spin-chirality decoupling" proposed recently really occurred or not, as well as various off-equilibrium phenomena induced by the chirality such as the violation of the fluctuation-dissipation relation. We performed a large scale Monte Carlo simulation of the 3D Heisenberg Edward-Anderson model, and have revealed the existence of a finite-temperature chiral-glass transition and of the spin-chirality decoupling phenomenon at long length and time scales, as predicted by the present author. It was also found that the peculiar one-step-like replica-symmetry breaking (RSB) occurred in the chiral-glass ordered state. In magnetic fields, this RSB gives rise to a thermodynamic SQ transition even in fields, which consistently explains the long-standing experimental puzzle for the in-field behavior of canonical spin glasses. The peculiar RSB pattern was indeed observed by means of off-equilibrium simulations of spin glasses via the violation of the fluctuation-dissipation theorem.