Supplementary Note: Numerical Model of Frequency‑Dependent Squeezing Attenuation on the UAT Scalar Attractor in LIGO O4

This Zenodo entry provides a supplementary technical note that explores a plausible physical mechanism for the complete absence of UAT scalar attractor detections during the fourth LIGO observing run (O4). It accompanies the main analysis suite deposited at DOI: 10.5281/zenodo.19955219, where the optimised UAT pipeline (172–260 Hz band, power‑line notches) achieves a time‑shifted false‑positive rate of 2.6 % and an off‑source rate of 9.2 % in O1–O3 data, but yields 0.0 % detections in O4. The present note describes a simplified numerical model in which frequency‑dependent squeezing (FDS) – introduced in O4 to reduce quantum shot noise – is simulated as additive Gaussian phase noise on the analytic strain signal. Applying this model to the O3 event GW170814 shows that the squeezing displaces the peak‑normalised RMS of the radial coherence from +0.0370 (within the ±0.05 UAT tolerance) to +0.0679 (outside the tolerance), thereby transforming a positive detection into a non‑detection. The model uses an effective squeezing factor of 0.75, consistent with the 2–3 dB noise reduction documented in the 172–260 Hz band for O4. Important limitations: This is a proof‑of‑concept simulation based on a single event and a constant phase‑noise approximation. It does not replace a full characterisation of the O4 detector response, nor does it claim to be the only explanation for the null result. It is offered as a quantitative hypothesis that demonstrates consistency between the UAT predictions, the known physics of squeezed light, and the observed absence of detections in O4. Readers are encouraged to consult the main validation suite (DOI: 10.5281/zenodo.19955219) for the complete set of stress tests and the underlying UAT/UPC theoretical framework.