The Unruh Effect and Theory Interpretation in an Effective Framework

I discuss the ontological implications of the Unruh effect if quantum field theory is taken to be an effective theory. In the context of the “algebraic” approach to the philosophy of quantum field theory, the Unruh effect can be exploited to construct arguments against particle interpretations. I argue that, since those arguments make use of the notion of fundamentality in a possible world, they cannot be understood in a framework that takes quantum field theory to be an effective theory. I then propose a reformulation that is valid for effective field theories. I conclude by noting that, given that analogous arguments against field interpretations can be made in the algebraic context but not in the effective one, arguments against particles from the Unruh Effect are much more powerful in the latter. I also present a method for interpreting effective theories along the way.