Constrained Torsion in an Informational Viscous Effective Field Theory: Dirac–Bergmann Reduction, Exact Bounce Cosmology, and Observable Signatures

We construct a constrained effective field theory in which spacetime torsion is not an independent dynamical degree of freedom but an algebraic composite operator determined by derivatives of an informational scalar field I. A full Dirac–Bergmann Hamiltonian analysis shows that torsion constraints are second-class and remove all torsional propagating modes. The resulting theory propagates exactly two tensor degrees of freedom, consistent with general relativity. The model yields a nonsingular cosmological bounce, modifies scalar perturbations through a scale-dependent sound speed in the infrared, and induces a phase shift in gravitational-wave propagation. The framework is formulated as a predictive, ghost-free effective field theory below a cutoff scale ΛEFT ∼ √γ/α, and reduces to general relativity in the ultraviolet limit.