Paper T15C: Frequency-Dependent Coherence notches in HLE v1 Stability-Grade Sustained-Hit Governance and Grid-Defined KPIs

This paper preserves the original T15C question—whether a sustained detector responsehas frequency-localized gaps—while rebuilding its test on the occupied-contact engine of therevised T15A. A time-dependent signed onsite term drives the prepared source at a declaredangular frequency; exact local phase rotations preserve each surface-channel inventory and thelocal contact balance, while an external-work identity records the energy supplied by the drive.T15B’s gauge-invariant angular diagnostics accompany a predeclared five-frequency sweep and asustained, site-fraction readout on the 917-site occupied graph. The computed sustained fractionsare 18/34 at zero frequency and 20/34 at each of the other four grid points, all above the declared0.2 decision fraction. Consequently this calculation finds no notches on its grid, even as theupper-tail mismatch changes substantially with drive frequency. This is a positive implementationand conservation test for frequency-dependent contact response; it does not establish a photon,a physically derived threshold, or a universal absence of notches. The complete reproduciblePython program and self-contained Windows runner are included.