Deeply bound meson-nuclear states: concepts and strategies

This presentation reviews recent developments in the understanding of low-energy pion- and kaon-nucleon interactions as they relate to deeply bound pionic atoms and possible antikaon-nuclear bound states. A brief update is given on 1s states of pionic atoms, summarizing their theoretical interpretation based on in-medium chiral effective field theory. This is followed by a state-of-the-art discussion of low-energy $\bar{K}N$ interactions, with special emphasis on the subthreshold region relevant to the proposed kaon-nuclear systems.