"Techniques to interface atomic systems with quantum optical fields form a cornerstone for future technologies that aim to exploit the laws of quantum physics for enhanced performance over classical devices. For example, quantum information processing is perhaps at the forefront of such possibilities, where photons can be used to relay information over large distances, while atoms naturally are physical systems that can process and store this information. The vast majority of atom-light interfaces developed thus far have been in relatively bulky geometries, such as atomic ensembles in free space or atoms coupled to macroscopic Fabry-Perot cavities. While remarkable progress has been made, these systems remain difficult to scale up and have limited functionality compared to the potential of atomic systems coupled with state-of-the-art nano-photonic devices.ATOMNANO will be a broad theoretical effort aimed at investigating novel techniques to trap cold atoms near nano-photonic structures, developing promising applications for these systems, and advancing theoretical tools to understand the emerging physics. The constituent projects will interface compelling ideas at the interface of several fields such as quantum optics, atomic physics, nano-photonics, quantum information science, and condensed matter physics. Furthermore, ATOMNANO will involve close collaborations with leading experimental groups in these fields to rapidly identify and coordinate the most promising and fundamentally new avenues for future research."