Second Sound as Coherent Δf Transport A USP Field Theory Interpretation ( msf:49125 )

Recent experiments have directly imaged second sound, demonstrating that heat can propagate as a coherent wave rather than by diffusion. This mini paper interprets second sound within USP Field Theory, where temperature corresponds to resonance disturbance (Δf) and heat transport reflects the coherence and geometry of that disturbance. Two transport regimes are distinguished: a general diffusive regime described by parabolic relaxation of Δf, and a coherent regime in which an inertial or relaxation term enables wave-like propagation with finite speed. In this framework, second sound represents the coherent limit of thermal transport rather than an anomaly.