We describe here how the late time behavior of the quantum mechanical decay of unstable states, which is predicted to deviate from an exponential form, may have important cosmological implications. It may increase the likelihood of eternal inflation and may enhance the likelihood of observing a small vacuum energy at late times versus possible late time decay into a large negative energy (anti–de Sitter space) vacuum state. Open questions include the following: How can internal observations made impact upon the wave function of the Universe and hence upon its decay characteristics?

• Received 12 November 2007

DOI:https://doi.org/10.1103/PhysRevLett.100.171301