Proposal for Static High-Field Experiment: Search for QED Vacuum Plastic Yielding (Version 4.0)

Update Log (Version 4.0 - Jan 2026): This revised version incorporates a comprehensive audit of the "Sieve Effect" predictions and refines the sensitivity analysis for the 30T hybrid magnet setup. Key updates include: Material Scaling: rigorous derivation of the lead-to-silicon yield threshold ratio (1:4.5). Risk Mitigation: Enhanced signal-to-noise analysis (SNR > 3 in pessimistic scenarios). Integration: Explicit parameter alignment with the newly released SV-TGD 4.0 framework. Executive Summary Core Question: Does the physical vacuum possess granular mechanical properties, specifically a finite shear yield strength, analogous to granular matter near the jamming transition? Theoretical Basis: This proposal is grounded in the SV-TGD 4.0 Framework, which models the vacuum as a hyper-jammed Face-Centered Cubic (FCC) lattice. This model has been empirically calibrated using the muonic hydrogen proton radius anomaly, identifying a critical vacuum density threshold ρ_c ≈ 2.3 × 10^31 m⁻³. Key Prediction (The Sieve Effect): Due to the "pre-stress" induced by atomic nuclei on the vacuum lattice, we predict a material-dependent yielding threshold. Specifically, Silicon is predicted to yield at a magnetic field approximately 4.5 times higher than Lead. Methodology: We propose utilizing the 30T Hybrid Magnet at EMFL to apply static, ultra-high field gradients (∇B ~ 10^3 T/m) to high-purity test masses. The vacuum yield signature will be sought as a non-linear "kink" in the force-field response curve, detected via interferometric cantilever sensing. Impact: A positive detection would constitute the first direct evidence of the granular nature of spacetime. A null result would establish a new lower bound on the vacuum shear modulus (τ_c > 2.4 × 10^10 Pa), constraining quantum gravity models.