Highly doubly excited states of the helium atom and the effects of nearresonant driving

尽管具有已知相互作用的三个带电粒子的问题看起来很简单，但我们仍然远远不能全面了解能谱的一般结构和两个电子原子的完全分裂。这个项目的目的是促进我们对高双激发态及其与光的相互作用的理解。我们主要关注在接近双电子原子破裂阈值的光谱中可以观察到的经典混合规则-混沌动力学的特征，以及在电磁场的作用下表现出来的电子关联，例如在双光子电离过程中，或者在两电子非色散波包的形成中。然而，对这一问题的理解确定了在复杂方法的帮助下面临的巨大的理论和数字挑战。这些方法将原子哈密顿量的适当表示与大规模的数值计算结合起来。

Despite the seeming simplicity of the problem of three charged particles with known interactions, we are still far from having a comprehensive knowledge of the general structure of the energy spectrum and of the complete breakup of two-electron atoms. The aim of this project is to advance our understanding of the regime highly doubly excited states and their interaction with light. We focus our attention on the signatures of the underlying classical mixed regular-chaotic dynamics that are expected to become observable in the spectrum close to the break-up-threshold of two-electron atoms, and on the electronic correlations that manifest under the action of an electromagnetic field, e.g., in two-photon ionization processes, or in the formation of two-electron nondispersive wave packets. The understanding of this issues defines, however, a formidable theoretical and numerical challenge which is faced with the help of sophisticated approaches. These combine appropriate representations of the atomic Hamiltonian with large scale numerical calculations.