Chris Mitsch - Some Lessons from Haag's Theorem

Abstract: Haag’s theorem is a classic no-go theorem: it rigorously demonstrates that there is a conflict between the interaction picture and other basic, intuitive-seeming assumptions in QFT. The precise significance of the theorem continues to be debated, however. I will focus on two big-picture questions in this talk. First, why are there multiple, distinct responses to Haag's theorem? Here I will compare and contrast these and, in so doing, articulate the methodological choices motivating them. Second, if our goal is building usable models of phenomena, why should we care about esoteric results like Haag's theorem? Here I will draw on an analogous result in the social sciences to make the case that results like Haag's theorem help us organize models' varied applications and prioritize investigations in model development.
Talk page: researchsemina...
Paper: philosophyofph...
3C-QFS, 19 September 2024