Symmetric-Bounce Quantum State of the Universe

Abstract

A proposal is made for the quantum state of the universe that has an initial state that is macroscopically time symmetric about a homogeneous, isotropic bounce of extremal volume and that at that bounce is microscopically in the ground state for inhomogeneous and/or anisotropic perturbation modes. The coarse-grained entropy is minimum at the bounce and then grows during inflation as the modes become excited away from the bounce and interact (assuming the presence of an inflaton, and in the part of the quantum state in which the inflaton is initially large enough to drive inflation). The part of this pure quantum state that dominates for observations is well approximated by quantum processes occurring within a Lorentzian expanding macroscopic universe. Because this part of the quantum state has no negative Euclidean action, one can avoid the early-time Boltzmann brains and Boltzmann solar systems that appear to dominate observations in the Hartle-Hawking no-boundary wavefunction.

25 page, LaTeX, references and several minor points added

References in corpus (26)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Sinks in the Landscape, Boltzmann Brains, and the Cosmological Constant Problem
• The Classical Universes of the No-Boundary Quantum State
• TASI Lectures on the Cosmological Constant
• The No-Boundary Measure of the Universe
• Is Our Universe Likely to Decay within 20 Billion Years?
• Are We Typical?
• Populating the Landscape: A Top Down Approach
• Boltzmann babies in the proper time measure
• A global picture of quantum de Sitter space
• Return of the Boltzmann Brains
• (No) Eternal Inflation and Precision Higgs Physics
• Geodesic measures of the landscape
• The Born Rule Dies
• Is Our Universe Decaying at an Astronomical Rate?
• Cosmological Measures without Volume Weighting
• Evidence for a bound on the lifetime of de Sitter space
• Boltzmann Brains--I'd Rather See Than Be One
• Entropy and initial conditions in cosmology
• Observational Selection Effects in Quantum Cosmology
• Black holes, information, and locality
• Typicality Derived
• No-Bang Quantum State of the Cosmos
• Typicality, Freak Observers and the Anthropic Principle of Existence
• Possible Anthropic Support for a Decaying Universe: A Cosmic Doomsday Argument
• Born Again

Cited by in corpus (6)

• Excluding Black Hole Firewalls with Extreme Cosmic Censorship
• Arrows of time and the beginning of the universe
• Bouncing universe from a modified dispersion relation
• Agnesi Weighting for the Measure Problem of Cosmology
• Finite Canonical Measure for Nonsingular Cosmologies
• Spacetime Average Density (SAD) Cosmological Measures