论文标题
在两轨哈伯德模型中，光诱导的激子秩序和拉比振荡的动力学
Photoinduced dynamics of excitonic order and Rabi oscillation in the two-orbital Hubbard model
论文作者
论文摘要
我们研究了在两轨哈伯德模型中摄影诱导的激子秩序增强的条件，该模型在我们以前的工作中已被理论上提出了[物理学。 Rev. B 97，115105（2018）]，并从Rabi振荡的角度进行分析。在平均场近似值中，我们模拟具有直接间隙的激子绝缘子的实时动力学，在该激素中，初始状态的对缩合具有BEC性质，并通过电偶极转变引入光激发。我们首先讨论，在原子限制中，我们的模型被简化为经历了拉比振荡的两级系统，因此，对于光辐射后的单个循环脉冲物质量基本上取决于拉比频率与泵光频率的比率。然后，显示出该图像即使在非零传递积分的情况下也存在，每个单粒子状态都表现出Rabi振荡，从而增强了激子秩序。我们证明了电子 - 光子相互作用的影响不会定性地改变结果。我们还通过小簇上的精确对角线化方法检查了多体动力学，这强烈表明，即使考虑到量子波动，我们的增强漏斗顺序的机制也可以生存。
We investigate the condition for the photoinduced enhancement of an excitonic order in a two-orbital Hubbard model, which has been theoretically proposed in our previous work [Phys. Rev. B 97, 115105 (2018)], and analyze it from the viewpoint of the Rabi oscillation. Within the mean-field approximation, we simulate real-time dynamics of an excitonic insulator with a direct gap, where the pair condensation in the initial state is of BEC nature and the photoexcitation is introduced by electric dipole transitions. We first discuss that in the atomic limit our model is reduced to a two-level system that undergoes the Rabi oscillation, so that for single cycle pulses physical quantities after the photoirradiation are essentially determined by the ratio of the Rabi frequency to the pump-light frequency. Then, it is shown that this picture holds even in the case of nonzero transfer integrals where each one-particle state exhibits the Rabi oscillation leading to the enhancement of the excitonic order. We demonstrate that effects of electron-phonon interactions do not alter the results qualitatively. We also examine many-body dynamics by the exact diagonalization method on small clusters, which strongly suggests that our mechanism for the enhancement of the exctionic order survives even when quantum fluctuations are taken into account.
