论文标题
在二维光激发哈伯德模型中，冲击电离电离和多个光子吸收
Impact ionization and multiple photon absorptions in the two-dimensional photoexcited Hubbard model
论文作者
论文摘要
我们研究了在短的电场脉冲的影响下，在U = 8处的4x3 Hubbard模型的非平衡响应，主要重点是多个光子激发以及脉冲后双重占用率的变化。行为主要取决于电场的驾驶频率。双重占用率最大的变化是在脉搏期间发生的。对于低于Mott GAP的频率，我们观察到大型场强度的多光子激发。对于差距能量以外的频率，在一个区域，螺旋螺旋重组降低了脉搏后的双重占用率。冲击电离（多激子产生），即脉搏后的双重占用率增长，是针对大于Mott GAP的两倍的频率。从Loschmidt振幅中，我们计算脉冲后量子状态的本征状光谱，观察到多个不同的光子激发峰，这与准粒子图片的期望一致。我们介绍了一种技术，我们通过该技术分析每个峰中双重占用率的时间演变。双重占用率的长期行为几乎仅取决于吸收的能量，我们探讨了该特性与本征态热假设的联系。
We study the non-equilibrium response of a 4x3 Hubbard model at U=8 under the influence of a short electric field pulse, with the main focus on multiple photon excitations and on the change of double occupancy after the pulse. The behavior mainly depends on the driving frequency of the electric field. The largest change of double occupancy occurs during the pulse. For frequencies below the Mott gap, we observe multiphoton excitations at large field intensities. For frequencies beyond the gap energy, there is a region where Auger recombination reduces the double occupancy after the pulse. Impact ionization (Multi Exciton Generation), namely a growing double occupancy after the pulse, occurs for frequencies larger than twice the Mott gap. From the Loschmidt amplitude we compute the eigenstate spectrum of the quantum state after the pulse, observing multiple distinct photon excitation peaks, in line with expectations from a quasiparticle picture. We introduce a technique with which we analyze the time evolution of double occupancy in each peak individually. The long-term behavior of the double occupancy almost only depends on the absorbed energy, and we explore the connection of this property to the Eigenstate Thermalization Hypothesis.
