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arXiv 2007.13263quant-phcond-mat.mtrl-sciphysics.optics
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磁超辐射相变

Magnonic Superradiant Phase Transition

Motoaki Bamba, Xinwei Li, Nicolas Marquez Peraca, Junichiro Kono

摘要:

我们表明,低温相变在ErFeO 3中发生在一个临界温度为4 K,可以被描述为超辐射相变(SRPT)的磁振子版本。在量子光学SRPT中,光子的作用由Fe磁振子起,而二能级原子的作用由Er自旋起。我们的自旋模型,这是减少到一个扩展的Dicke模型,考虑到除了Fe磁振子介导的长程Er-Er相互作用的Er自旋之间的短程,直接交换相互作用。通过使用最近的太赫兹磁谱和磁化实验确定的现实参数,我们证明,这是合作,超强耦合的Er自旋和Fe磁振子之间的相变的原因。因此,这项工作证明了ErFeO 3是一个独特的系统,表现出SRPT在热平衡,与以前的观察激光驱动的非平衡SRPT。

英文摘要:

We show that the low-temperature phase transition in ErFeO3 that occurs at a critical temperature of ~ 4 K can be described as a magnonic version of the superradiant phase transition (SRPT). The role of photons in the quantum-optical SRPT is played by Fe magnons, while that of two-level atoms is played by Er spins. Our spin model, which is reduced to an extended Dicke model, takes into account the short-range, direct exchange interactions between Er spins in addition to the long-range Er-Er interactions mediated by Fe magnons. By using realistic parameters determined by recent terahertz magnetospectroscopy and magnetization experiments, we demonstrate that it is the cooperative, ultrastrong coupling between Er spins and Fe magnons that causes the phase transition. This work thus proves ErFeO3 to be a unique system that exhibits a SRPT in thermal equilibrium, in contrast to previous observations of laser-driven non-equilibrium SRPTs.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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