Photoionizations of electrons floating on liquid Helium

Photo-induced ionizations of natural atoms and molecules have been investigated extensively, and the photoelectron spectroscopic techniques have applied in various fields. However, the photoionizations of various artificial atoms have been hardly investigated, although their quantum coherent manipulations for quantum information applications have been paid much attention in recent years. Here, we focus on the photo-induced ionizations of one of the typical artificial atoms, i.e., the Hydrogen-like atoms generated by the single electrons floating on liquid Helium. By using the usual Fermi's golden rule, we theoretically calculate the photo-induced ionized rate and cross section of the Hydrogen-like atom gas under the light irradiations. The relevant photocurrents, which are experimentally measured, are also calculated. Hopefully, these results could be verified in the future experiments and are useful for various potential applications in quantum computation, precise measurements of Planck constant, and the images of single electrons, etc.