Finding non-signalling agents and subsystems in global theories
Lidia del Rio, University of Bristol
How can we find operational notions of local agents within a global theory? In this talk, I will present an operational way to model the effective state spaces of individual agents, as well as the range of their actions. I will then address the aspects of locality relevant to derive independence and non-signalling conditions between agents. This approach establishes an operational connection between local action and local observations, and gives a global interpretation to concepts like discarding a subsystem or composing local functions.
This work has applications both in foundational physics and in experiment. In the former, it allows us to start from a field theory (or other global description) and find meaningful descriptions of local agents and subsystems. In experiment, it gives us a procedure to find and test effective subsystems (like independent logical qubits) in complicated setups.
This is joint work with Lea Krämer, based partly on arXiv:1511.08818.