Kasia Rejzner (University of York) – Quantum Reference Frames and their impact on algebraic structures in QFT

I will begin by introducing the framework of algebraic quantum field theory (AQFT), including its formulation on curved spacetimes, and outline how measurements can be described within this setting following the approach of Fewster and Verch.

Within this framework, I will show that the presence of symmetries necessitates the use of quantum reference frames in order to distinguish between measurements related by symmetry transformations. Incorporating quantum reference frames has nontrivial implications for the structure of the observable algebras that arise, shedding light on recent observations by Chandrasekaran, Longo, Penington, and Witten in the context of QFT on de Sitter spacetime. The talk will be primarily based on my joint work with Fewster, Janssen, Loveridge, and Waldron, “Quantum reference frames, measurement schemes and the type of local algebras in quantum field theory.”