Runaway particle production in de Sitter space

Abstract
We examine a particle-production mechanism for scalar λϕ4 theory in de Sitter space which has the feature that the rate of particle production is proportional to the number of particles present, yielding an exponentially increasing rate of production. General arguments strongly suggest that this process is generic to any renormalizable interacting theory on de Sitter space. The interpretation of this process and its relation to the response of freely falling "particle detectors" is discussed.