Cosmic Birefringence from Finite-Response Photon Transport in an Emergent Condensate Superfluid Medium

Cosmic birefringence is investigated as a finite-response photon-transport effect in the Emergent Condensate Superfluid Medium (ECSM). In a static, non-expanding cosmology, polarization rotation is accumulated through a parity-odd response of the coherent medium following the CMB transparency transition. The framework predicts distinguishable transition and bulk contributions and can be tested through CMB-versus-radio rotation, frequency dependence, anisotropic birefringence, and multipole structure. Recent ACT+Planck measurements are consistent with the previously considered ECSM response range, although the microscopic parity-odd coupling remains to be derived.