Search for Anomalous Strong-Field Vacuum Dispersion: An Experimental Hypothesis

This work presents an experimental hypothesis exploring the possibility of anomalous vacuum dispersion effects under extreme electromagnetic field intensities approaching the strong-field QED regime. The paper does not claim superluminal signal propagation. Instead, it proposes differential, testable observables based on timing and phase diagnostics in pump–probe laser configurations. The goal is to motivate laboratory-based experimental constraints or verification of intensity-dependent vacuum optical properties, with potential relevance to fundamental electrodynamics and early-universe cosmology.