Application of Quantum Darwinism to Diffusion during Cosmic Inflation

A baby-universe model of cosmic inflation is analyzed using quantum Darwinism. In this model cosmic inflation can be approximated as Brownian motion of a quantum field, and quantum Darwinism implies that decoherence is the result of quantum Brownian motion of the wave function. The quantum Darwinism approach to decoherence in the baby-universe cosmic-inflation model yields the decoherence times of the baby-universes. The result is the equation relating the baby-universe's decoherence time with the Hubble parameter. A brief discussion of the relation between Darwinism and determinism is provided in the Appendix.