Heretics of the False Vacuum: Gravitational Effects On and Of Vacuum Decay 2

TL;DR

The paper questions the universality of vacuum decay in quantum gravity, arguing that CDL-style instantons do not robustly guarantee transitions between maximally symmetric vacua such as flat or AdS spaces. It proposes that decay, when it occurs, yields open FRW cosmologies and often ends in a Big Crunch for negative Λ, challenging common interpretations of AdS/CFT. The analysis extends to de Sitter space, suggesting dS-to-dS transitions may be thermal and observer-dependent, but lacks a definitive instanton proof and highlights singular flat-space limits. The work emphasizes that effective potential methods and semiclassical instantons have limited applicability in quantum gravity and calls for cautious interpretation in string theory and cosmology, with concepts like asymptotic darkness and holography guiding the constraints. Overall, it reframes vacuum decay as a subtle, context-dependent phenomenon requiring a full quantum-gravity treatment beyond traditional instanton calculus.

Abstract

This paper reexamines the question of vacuum decay in theories of quantum gravity. In particular it suggests that decay into stable flat or AdS vacua, never occurs. Instead, vacuum decay occurs, if at all, into a cosmological spacetime. If the latter has negative cosmological constant, it undergoes a Big Crunch, which suggests that the whole picture is inconsistent. The question of decay of de Sitter space must be very carefully defined.