Hydrodynamic Dual-Vacuum Unification: From Swirl Superradiance to Photon Torsion and Atomic Stability

We develop a falsifiable hydrodynamic extension of field theory in which the vacuum consists of two interacting, incompressible continua: a fast electromagnetic sector with characteristic propagation speed c, and a slower rotational Swirl sector with speed |v⟲| ∼ 10^6 m/s. Using Helmholtz–Kelvin vortex dynamics, we show that acceleration excites vorticity stretching rather than compression, producing a primary Swirl burst with characteristic delay τS ∼ 0.1 ns. Because electromagnetic cavities suppress shear-wave impedance by κse ∼ 10^−7, this burst dissipates non-radiatively, leaving a secondary photon “Unruh Echo” at ∼ 30 ns—the signal observed in recent cavity superradiance experiments. We formulate a coupled-rate theory of Swirl–EM energy flow, introduce a torsion-modified Maxwell equation, derive a parity-odd linear-in-B vacuum birefringence, and propose a BEC vortex-lattice experiment capable of distinguishing this dual-vacuum picture from standard quantum field theory.