掺杂陈铁磁体的非平衡动力学：假真空衰变的案例研究
Nonequilibrium dynamics of doped Chern ferromagnets: a case study for false vacuum decay
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中文总结 AI 辅助
本文研究掺杂陈铁磁体的非平衡动力学，借助光泵浦制备真真空泡，发现其衰变时间随填充因子变化，揭示铁磁畴非平衡动力学对陈绝缘体态附近填充因子的高敏感性。
中文摘要 AI 辅助
尽管亚稳态假真空衰变在物理学中普遍存在，但其 underlying dynamics 仍未被充分理解。莫尔量子材料中的耗散态制备为探索这一物理现象提供了绝佳环境，因为它可生成系统哈密顿量基态之外的奇异量子态。受近期演示空穴自旋-谷自由度稳态光取向的实验启发，我们研究了存在反向磁场时巡游陈铁磁体的动力学。使用圆偏振拉盖尔-高斯光束的光泵浦使我们能确定性制备嵌入亚稳态中的真真空泡。根据泵浦功率控制的初始泡尺寸，我们观察到泡因畴壁与体动力学的相互作用而发生坍缩或膨胀。当外磁场与铁磁性矫顽场相当、对应整数和分数陈绝缘体态的 commensurate 填充时，我们观察到自旋极化衰变时间延长了两个数量级。我们的实验表明，铁磁畴的非平衡动力学对陈绝缘体态附近的精确填充因子，比标准输运或光学测量敏感得多。
英文摘要
Even though metastable false vacuum decay is ubiquitous in physics, its underlying dynamics are still not well understood. Dissipative state preparation in moiré quantum materials provides an exceptional setting for exploring this physics since it allows the possibility of generating exotic quantum states that are not the ground state of the system Hamiltonian. Motivated by recent experiments demonstrating steady-state optical orientation of the spin-valley degree of freedom of holes, here we investigate dynamics of itinerant and Chern ferromagnets in the presence of an opposing magnetic field. Optical pumping using a circularly polarized Laguerre-Gauss beam allows us to deterministically prepare a true vacuum bubble embedded inside a metastable state. Depending on its initial size controlled by the pump power, we observe that the bubble collapses or expands due to an interplay between domain wall and bulk dynamics. For external magnetic fields comparable to the coercive field of ferromagnetism, we observe up to two-orders-of-magnitude prolongation of the spin polarization decay time at commensurate fillings corresponding to integer and fractional Chern insulator states. Our experiments reveal that the nonequilibrium dynamics of the ferromagnetic domains is substantially more sensitive to the precise filling factor around Chern insulator states than standard transport or optical measurements.
