Measurement as Horizon Activation

This paper proposes an operational reformulation of measurement as a horizon-activation process rather than a dynamical collapse or stochastic projection. Measurement is identified with the activation of an accessibility boundary that partitions operationally distinguishable degrees of freedom from inaccessible ones. Within this framework, classical outcomes emerge from horizon-induced rank reduction in the accessible observable algebra, without invoking wavefunction collapse, observer consciousness, or hidden variables. The analysis connects quantum measurement, decoherence, and classical emergence through a unified horizon-based language applicable across quantum, relativistic, and information-theoretic contexts. Zenodo Keywords Measurement problem Horizons Operational physics Quantum measurement Information accessibility Rank collapse Decoherence Ordered-Dynamics Reconstruction Program