What Reference Frames Teach Us. Part I: About Symmetry Principles and Observability

Understand

This paper is an exploration of the nuanced realm of reference frames within the framework of General Relativity.

• Our analysis exposes a violation of Earman's SP1 principle in scenarios involving fields that are dynamically uncoupled, a common assumption for reference frames.
• Unlike other violations, we cannot foreclose it by eliminating background spacetime structure.
• Our analysis also leads us to challenge the conventional notion of partial observables as quantities that are associated with a measuring instrument and expressed within a coordinate system.