A Bell-Style Cosmic-Setting Test for Detecting Spacetime Phase-Structure (SP3) Transport Fingerprints

Cosmic Bell tests employ photons from distant astronomical sources to determine
measurement settings, thereby constraining local hidden-variable models by extending the
causal origin of experimental choices deep into the past. These experiments implicitly
assume that photons arriving from cosmological distances constitute an unbiased,
transport-neutral sample of emitted states. The Spacetime Phase-Structure (SP3)
framework introduces a distinct possibility: that long-baseline propagation through
structured vacuum-phase coherence domains may selectively condition transport modes,
introducing subtle, path-dependent statistical skews without altering Bell-inequality
violations themselves.
Here we propose a Bell-style experimental variant designed not to test locality or realism,
but to probe transport-level neutrality of light propagation. The protocol compares
polarization statistics and randomness metrics derived from cosmic photons spanning
controlled age and propagation-distress cohorts, while holding laboratory entanglement,
detection hardware, and Bell analysis fixed. The experiment is executable with existing
quantum-optical and astronomical instrumentation and yields falsifiable outcomes that
either reveal or constrain SP3-style coherence-filtering effects in spacetime transport.