Quantum Gravity and Resonant Shell Cosmology: Boundary-Induced Decoherence and the Emergence of Spacetime

Abstract We extend Resonant Shell Cosmology (RSC) to incorporate quantum gravitational effects at the cosmological boundary. In RSC, the observable universe occupies a closed Friedmann-Robertson-Walker domain bounded by a dynamic, reflective shell whose surface stress-energy drives cosmic acceleration without dark energy. Here we demonstrate that this boundary provides a natural resolution to the quantum measurement problem through gravitationally-induced decoherence. The shell functions as a quantum-classical interface where Planck-scale boundary interactions continuously collapse superpositions, generating both the thermodynamic arrow of time and the emergence of classical spacetime from quantum geometry. We derive the decoherence rate from first principles using the shell's surface gravity and show it matches observational constraints. The framework predicts a specific relationship between the cosmological constant problem and boundary entropy, suggests that bubble nucleation in a multiverse follows from standard quantum gravity without additional assumptions, and offers falsifiable signatures in CMB spectral distortions and gravitational wave backgrounds. The mathematical duality between black hole horizons and cosmological shells emerges naturally from the quantum gravity treatment, suggesting boundaries are fundamental to the quantum-classical transition at all scales.