Recently, it has been shown theoretically that strongly non-paraxial Bessel beams can exert an optical force on a particle that drags the latter towards the light source. However, an experimental verification of the existence of an optical drag force (ODF) with Bessel beams is very challenging. In the first subproject, we therefore propose to theoretically investigate the possibility of realizing an ODF acting on particles in the evanescent field of highly non-paraxial modes sustained by high-index optical nanofibers. Nanofiber modes are promising candidates for such investigations because they can exhibit wormhole regions with negative Poynting vector in their evanescent field. Moreover, a possible ODF could be straightforwardly demonstrated because the mode might provide both the tractor force and a gradient force that automatically traps the particles in the region with a backward force. Beyond the fundamental interest of demonstrating an ODF, its implementation with nanofiber modes may find important applications in both science and technology.In the second subproject, we propose to theoretically investigate cavity quantum electrodynamical (CQED) effects for an ensemble of fiber-trapped atoms coupled to a nanofiber-based cavity (NFC). Due to the strong lateral confinement of the NFC mode, the CQED effects prevail even if the NFC finesse is moderate (∼100) and the resonator is comparatively long (∼10 cm). Such NFCs have recently been demonstrated experimentally. Moreover, cold neutral atoms have recently been trapped and optically interfaced in the evanescent field surrounding optical nanofibers. It is therefore very timely highly appealing to consider the combination of NFCs with such nanofiber-trapped atoms. We will therefore establish the theoretical framework for the novel system and explore its potential for controlling the flow of light and for light-light interaction at the single quantum level.