This paper seems to be pretty applied, but I've only skimmed the intro: https://arxiv.org/pdf/1504.05625.pdf https://arxiv.org/pdf/1504.05625.pdf That starts

This paper seems to be pretty applied, but I've only skimmed the intro: https://arxiv.org/pdf/1504.05625.pdf https://arxiv.org/pdf/1504.05625.pdf That starts to make sense to me as a sort of generalized framework for Feynman-diagram-like things. Explains why particle physicists would be drawn to category theory as well. Feels like there's still probably a hell of a lot of dots to connect there though.