Robustness of the Ratio ≈ 1 Collapse Test Against Uncertainties in Gravity and Mass Density

This methods note evaluates the robustness of the “Ratio approximently equal 1” collapse-gate test—where gravitational‐memory imprint GmG_mGm and local mass density MdM_dMd satisfy gravity memory/Mass Density approximently equal 1—against systematic uncertainties in key parameters. Focusing on the FAU “Twisted-Light” fiber-loop experiment (560 m, 1550 nm loop, 50 MHz, 80 fs pulses), the author demonstrates that common fractional biases in Newton’s constant gravity or Earth’s density cancel out when determining the unity crossing. Using CODATA 2022 values and GRACE/GRACE-FO density models, the note tabulates relative uncertainties and shows that even a 10 % shared calibration error leaves the critical threshold invariant. Historical precedents (e.g., Gravity Probe B) reinforce the cancellation argument. An explicit five‐step implementation protocol is provided, guiding future tests of gravity’s instantaneous or finite-speed behavior. The note concludes that the collapse-gate signal is immune to calibration bias, making it a referee-ready blueprint for high-precision tests of new physics.