IAS Physics Group Meeting

Abstract: While von Neumann entropies for local subregions in quantum field theory universally contain ultraviolet divergences, there is widespread belief that differences between von Neumann entropies can be finite and well-defined in many physically relevant scenarios. I will make this precise by leveraging the "crossed-product" as a natural regulator. The continuum limit unambiguously leads to formulas for entropy differences that coincide with heuristic formulas widely used in the literature and has the properties that an entropy difference "should." As an application, I will prove a version of the Bekenstein bound.