Cosmological Classicalization: Maintaining Unitarity under Relevant   Deformations of the Einstein-Hilbert Action
  Generic relevant deformations of Einstein's gravity theory contain additional degrees of freedom that have a multi-facetted stabilization dynamics on curved spacetimes. We show that these relevant degrees of freedom are self-protected against unitarity violations by the formation of classical field lumps that eventually merge to a new background geometry. The transition is heralded by the massive decay of the original vacuum and evolves through a strong coupling regime. This process fits in the recently proposed classicalization mechanism and extends it further to free field dynamics on curved backgrounds. 
Felix Berkhahn, Dennis D. Dietrich, and Stefan Hofmann
hep-th gr-qc hep-ph