Cosmological Classicalization: Maintaining Unitarity under Relevant Deformations of the Einstein-Hilbert Action

TL;DR

The paper demonstrates that relevant deformations of Einstein's gravity lead to classical field lumps that preserve unitarity by transitioning to a new background, extending the classicalization concept to curved spacetimes.

Contribution

It introduces a mechanism where classicalization protects unitarity in deformed gravity theories on curved backgrounds, expanding previous flat spacetime models.

Findings

Formation of classical field lumps prevents unitarity violation.

Transition involves decay of the original vacuum and strong coupling dynamics.

Extension of classicalization mechanism to curved spacetime contexts.

Abstract

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.