Angular Echo and Topological Loop Bias from Temporal Gradients

This extension note derives falsifiable laboratory signatures of scalar temporal gradients, including angular echo asymmetry and topological loop bias under circulation reversal. Null protocols (angle reversal and loop scrambling) provide clean falsification conditions. Additional bandwidth shifts, gravitational-wave ringdown modulation estimates, and a cosmological loop-bias sketch are included. Experimental sensitivities are tabulated and consistent with NMR echo dynamics, photonic index gradients, BEC vortices, and polarization-rotation surveys. This work complements the Scalar Temporal Field Ontology by providing testable laboratory access points.