We theoretically study THz-light-driven high-harmonic generation (HHG) in the spin-liquid states of the Kitaev honeycomb model with a magnetostriction coupling between spin and electric polarization. To compute the HHG spectra, we numerically solve the Lindblad equation, taking account of the dissipation effect. We find that isotropic Kitaev models possess a dynamical symmetry, which is broken by a static electric field, analogous to HHG in electron systems. We show that the HHG spectra exhibit characteristic continua of Majorana fermion excitations, and their broad peaks can be controlled by applying static electric or magnetic fields. In particular, the magnetic-field dependence of the HHG spectra drastically differs from those of usual ordered magnets. These results indicate that an intense THz laser provides a powerful tool to observe dynamic features of quantum spin liquids.

中文翻译：

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Kitaev 自旋液体中的线性和非线性光学响应

我们从理论上研究了自旋和电极化之间具有磁致伸缩耦合的 Kitaev 蜂窝模型的自旋液体状态下的太赫兹光驱动高次谐波产生 (HHG)。为了计算 HHG 光谱，我们对 Lindblad 方程进行数值求解，同时考虑到耗散效应。我们发现各向同性 Kitaev 模型具有动态对称性，它被静态电场破坏，类似于电子系统中的 HHG。我们表明 HHG 光谱表现出马约拉纳费米子激发的特征连续性，并且它们的宽峰可以通过施加静电或磁场来控制。特别是，HHG 谱的磁场依赖性与通常有序磁体的磁场依赖性截然不同。