Pumping graphene with circularly polarized light is the archetype of light-tailoring topological bands. Realizing the induced Floquet-Chern insulator state and demonstrating clear experimental evidence for its topological nature has been a challenge, and it has become clear that scattering effects play a crucial role. We tackle this gap between theory and experiment by employing microscopic quantum kinetic calculations including realistic electron-electron and electron-phonon scattering. Our theory provides a direct link to the build-up of the Floquet-Chern insulator state in light-driven graphene and its detection in time- and angle-resolved photoemission spectroscopy (ARPES). This allows us to study the robustness of the Floquet features against dephasing and thermalization effects. We also discuss the ultrafast Hall response in the laser-heated state. Furthermore, the induced pseudospin texture and the associated Berry curvature gives rise to momentum-dependent orbital magnetization, which is reflected in circular dichroism in ARPES (CD-ARPES). Combining our nonequilibrium calculations with an accurate one-step theory of photoemission allows us to establish a direct link between the build-up of the topological state and the dichroic pump-probe photoemission signal. The characteristic features in CD-ARPES are shown to be stable against heating and dephasing effects. Thus, tracing circular dichroism in time-resolve photoemission provides new insights into transient topological properties.

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如何在时间和角度分辨的光发射中使用圆二色性来光谱检测石墨烯中的瞬态拓扑状态

圆偏振光泵浦石墨烯是光剪裁拓扑带的原型。实现诱导的Floquet-Chern绝缘子状态并为其拓扑性质提供清晰的实验证据一直是一个挑战，而且很明显散射效应起着至关重要的作用。我们通过采用微观量子动力学计算（包括实际的电子-电子和电子-声子散射）来解决理论与实验之间的差距。我们的理论为光驱动石墨烯中Floquet-Chern绝缘子状态的建立及其在时间和角度分辨的光发射光谱（ARPES）中的检测提供了直接的联系。这使我们能够研究Floquet功能对移相和热化作用的鲁棒性。我们还将讨论激光加热状态下的超快霍尔响应。此外，诱导的伪自旋织构和相关的贝里曲率引起了动量相关的轨道磁化，这反映在ARPES（CD-ARPES）的圆二色性中。将我们的非平衡计算与精确的一步法光发射理论相结合，可以使我们在拓扑状态的建立与二向色泵浦探针光发射信号之间建立直接联系。CD-ARPES的特征表明对加热和移相效果稳定。因此，在时间分辨光发射中追踪圆形二向色性提供了对瞬态拓扑特性的新见解。这反映在ARPES（CD-ARPES）的圆二色性中。将我们的非平衡计算与精确的一步法光发射理论相结合，可以使我们在拓扑状态的建立与二向色泵浦探针光发射信号之间建立直接联系。CD-ARPES的特征表明对加热和移相效果稳定。因此，在时间分辨光发射中追踪圆形二向色性提供了对瞬态拓扑特性的新见解。这反映在ARPES（CD-ARPES）的圆二色性中。将我们的非平衡计算与精确的一步法光发射理论相结合，可以使我们在拓扑状态的建立与二向色泵浦探针光发射信号之间建立直接联系。CD-ARPES的特征表明对加热和移相效果稳定。因此，在时间分辨光发射中追踪圆形二向色性提供了对瞬态拓扑特性的新见解。CD-ARPES的特征表明对加热和移相效果稳定。因此，在时间分辨光发射中追踪圆形二向色性提供了对瞬态拓扑特性的新见解。CD-ARPES的特征表明对加热和移相效果稳定。因此，在时间分辨光发射中追踪圆形二向色性提供了对瞬态拓扑特性的新见解。