Seven Trajectories, One Curve: Cross-Grid Evidence for a Graded Coherence Response

Abstract

This record reports a graded, cross-grid dose-response relationship in a coherence-based stress measurement across seven independent power-grid events on two U.S. transmission systems (ERCOT, PJM). Using a single, fixed coherence formula — C_ij(τ) = 1 − |x_i(τ) − x_j(τ)| / σ_ij — applied identically across all events with no per-event tuning, this record shows that the minimum measured coherence tracks an independently established severity ordering (generation capacity offline, natural gas production loss, event duration) as a continuous, graded relationship rather than a binary split between “storm” and “not storm.” This is the structural signature of an instrument calibration curve: the measurement varies with a stressor whose magnitude was established by other means, not by the measurement itself. Key findings: • Two independent negative controls (administrative demand data, wholesale market price data) confirm the measurement discriminates real stress from ordinary conditions, with 25× and 272× separation respectively between storm and non-storm weeks. • The relationship replicates out-of-sample on a second Scope and limitations, stated directly: this is a Tier-1 record. No precursor, leading-indicator, or predictive claim is made — all lag-correlation tests were negative. No Drift, Rupture, Shift, Kink, Stress, or Quench operator computation is reported here; only the raw coherence measurement is computed and verified. At N=7 events, this record cannot yet distinguish a genuinely continuous relationship from two clusters bridged by intermediate points, and event severity and duration remain confounded across the tested set — every short event tested is null and every multi-day event shows sustained depression. These are identified as the specific open questions a continuation of this work would need to resolve. Prepared by the Upstream Coherence Measurement Stratum (UCMS). Data sources: ERCOT Native Load and Historical RTM LMP (public), EIA Henry Hub spot price (public), PJM Data Miner 2 hrl_load_metered feed (public). • The Geometry of Now, Vol. IV (D/S/K/R/Q operator definitions) — https://doi.org/10.5281/zenodo.21271877 Uri Precursor Window (earlier precursor-detection analysis using autocorrelation-based early warning signals; note: this record’s own direct Drift computation — dC/dt on the same event — finds its steepest excursion occurring after, not before, the coherence minimum. The two results have not yet been reconciled on a common method; this is flagged as an open question, not a resolved contradiction, since autocorrelation and Drift are measuring https://doi.org/10.5281/zenodo.21513174 • Coherence Physics Research Program: A Living Map of SCFL/UCMS Operators, Evidence Status, and Open Replication Gaps — the parent program map tracking evidence status across the full operator family and stating the canon’s outstanding replication gap directly — https://doi.org/10.5281/zenodo.21728822