Ultrafast Dynamics of Individual Quantum States in Condensed Matter

Electronic functionality relies on the controlled movement of excited charges through integrated semiconductor nanostructures. Advancing quantum technologies requires not only harnessing the unique electronic, magnetic, and topological properties of quantum materials but also achieving precise control over individual quantum states. A fundamental challenge in experimental physics is to directly observe and track these quantum states in complex materials. Time- and angle-resolved photoemission spectroscopy (trARPES) provides a quantum-state-resolved perspective on the ultrafast dynamics of many-body states, such as excitons, in non-equilibrium conditions. By capturing the formation and scattering of excitons in momentum space in real time, trARPES reveals key properties, including binding energy, exciton-phonon interactions, and the spatial distribution of many-body wavefunctions [1], [2]. Furthermore, multidimensional trARPES signals encode critical information about orbital characteristics and Berry curvature [3]. When applied to heterostructures, this technique uncovers the fundamental mechanisms governing ultrafast exciton and charge transport across interfaces, shedding light on charge and energy transfer processes [4], [5]. In this talk, we will demonstrate the power of this approach for transition metal dichalcogenide heterostructures, molecular crystals, and layered semiconducting antiferromagnets.