Speaker
Description
Existing approaches to relativistic quantum reference frames typically begin by assuming Lorentz or Poincaré symmetry and then constructing quantum frame transformations compatible with that structure. Here we propose an alternative route based on a minimal physical postulate: the existence of a perspective-invariant maximal velocity. Working within a timeless, constraint-based formulation in which spatial and temporal coordinates are treated as quantum observables, we introduce constraints that implement this requirement. We then analyze how the resulting constraint structure restricts the admissible transformations between spatiotemporal quantum reference frames. Observable coordinate time emerges relationally through conditional probabilities, connecting the construction to the Page-Wootters mechanism while extending it toward a relativistic spatiotemporal setting. Finally, we identify the conditions that such a framework must satisfy to recover full Lorentz covariance from the constraint structure alone.