Populating the Landscape: A Top Down Approach

Abstract

We put forward a framework for cosmology that combines the string landscape with no boundary initial conditions. In this framework, amplitudes for alternative histories for the universe are calculated with final boundary conditions only. This leads to a top down approach to cosmology, in which the histories of the universe depend on the precise question asked. We study the observational consequences of no boundary initial conditions on the landscape, and outline a scheme to test the theory. This is illustrated in a simple model landscape that admits several alternative inflationary histories for the universe. Only a few of the possible vacua in the landscape will be populated. We also discuss in what respect the top down approach differs from other approaches to cosmology in the string landscape, like eternal inflation.

22 pages, 1 figure

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Cited by in corpus (39)

• Dark Energy
• Inflationary Cosmology
• The Measure Problem in Cosmology
• Sinks in the Landscape, Boltzmann Brains, and the Cosmological Constant Problem
• The Classical Universes of the No-Boundary Quantum State
• The No-Boundary Measure of the Universe
• Life at the Interface of Particle Physics and String Theory
• Review of the No-Boundary Wave Function
• Quantum state of the multiverse
• A measure of the multiverse
• Local Observation in Eternal inflation
• The No-Boundary Measure in the Regime of Eternal Inflation
• Susskind's Challenge to the Hartle-Hawking No-Boundary Proposal and Possible Resolutions
• Pre-Inflationary Spacetime in String Cosmology
• Islands in the landscape
• Toward inflation models compatible with the no-boundary proposal
• Predicting a Prior for Planck
• Novel higher-curvature variations of $R^2$ inflation
• Dynamics of false vacuum bubbles with nonminimal coupling
• The no-boundary measure in scalar-tensor gravity
• Islands in Multiverse Models
• Anthropic Bounds on Lambda from the No-Boundary Quantum State
• Replication Regulates Volume Weighting in Quantum Cosmology
• Probabilities in the landscape
• No-boundary measure and preference for large e-foldings in multi-field inflation
• Hartle-Hawking boundary conditions as Nucleation by de Sitter Vacuum
• A Note on the Quantum Creation of Universes
• Vacuum Bubble in an Inhomogeneous Cosmology
• Symmetric-Bounce Quantum State of the Universe
• No-boundary wave function for two-field inflation
• The Measure for the Multiverse and the Probability for Inflation
• No-Bang Quantum State of the Cosmos
• Cosmic eggs to relax the cosmological constant
• Sharp Predictions from Eternal Inflation Patches in D-brane Inflation
• How to Create Universes with Internal Flux
• Stephen William Hawking: A Biographical Memoir
• Abelian Varieties, RCFTs, Attractors, and Hitchin Functional in Two Dimensions
• Delicate curvature bounces in the no-boundary wave function and in the late universe
• The No-Boundary Probability for the Universe starting at the top of the hill