Watchers of the multiverse

Abstract

An unresolved question in inflationary cosmology is the assignment of probabilities to different types of events that can occur in the eternally inflating multiverse. We explore the possibility that the resolution of this "measure problem" may rely on non-standard dynamics in regions of high curvature. In particular, "big crunch" singularities at the future boundary of bubbles with negative vacuum energy density may lead to bounces, where contraction is replaced by inflationary expansion driven by different vacua in the landscape. Similarly, singularities inside of black holes might be gateways to other inflating vacua. This would drastically affect the global structure of the inflating multiverse. We consider a measure based on a probe geodesic which undergoes an infinite number of passages through crunches. This can be thought of as the world-line of an eternal "watcher", collecting data in an orderly fashion. We compare this to previous approaches to the measure problem. The watcher's measure is independent of initial conditions and does not suffer from ambiguities associated with the choice of a cut-off surface. Another potential benefit from passing through crunches is that the observations collected by the watcher may easily depart from ergodicity, in very generic landscapes. This may significantly alleviate the problem of Boltzmann Brain dominance.

29 pages, 5 figures, minor corrections, references added

References in corpus (14)

• Quantum Nature of the Big Bang
• Holographic probabilities in eternal inflation
• Predicting the cosmological constant with the scale-factor cutoff measure
• Properties of the scale factor measure
• Quantum nature of cosmological bounces
• Holographic Multiverse
• Complementarity in the Multiverse
• Geodesic measures of the landscape
• Stationary Measure in the Multiverse
• Eternal observers and bubble abundances in the landscape
• A geometric solution to the coincidence problem, and the size of the landscape as the origin of hierarchy
• The Static Quantum Multiverse
• Eternal Inflation With Non-Inflationary Pocket Universes
• The scale of gravity and the cosmological constant within a landscape

Cited by in corpus (25)

• Inflationary paradigm after Planck 2013
• Black holes and the multiverse
• A Cosmological Super-Bounce
• Obtaining the CMB anomalies with a bounce from the contracting phase to inflation
• Schwinger effect in de Sitter space
• Primordial Black Holes from Cosmic Domain Walls
• Clustering of primordial black holes from quantum diffusion during inflation
• Computational complexity of the landscape II - Cosmological considerations
• Arrows of time and the beginning of the universe
• Formation of trapped vacuum bubbles during inflation, and consequences for PBH scenarios
• The Multiverse and Particle Physics
• Search Optimization, Funnel Topography, and Dynamical Criticality on the String Landscape
• Accessibility Measure for Eternal Inflation: Dynamical Criticality and Higgs Metastability
• Non-singular bounce transitions in the multiverse
• Non-singular AdS-dS transitions in a landscape scenario
• Galaxy Formation Efficiency and the Multiverse Explanation of the Cosmological Constant with EAGLE Simulations
• A quantum measure of the multiverse
• The interacting multiverse and its effect on the cosmic microwave background
• Galilean Islands in Eternally Inflating Background
• Inflation in Random Landscapes with two energy scales
• Bayesian Reasoning in Eternal Inflation: A Solution to the Measure Problem
• Black holes and up-tunneling suppress Boltzmann brains
• 4-volume cutoff measure of the multiverse
• New Inflation in the Landscape and Typicality of the Observed Cosmic Perturbation
• Eternal Inflation with Arrival Terminals