Inflation and Eternal Inflation

Abstract

The basic workings of inflationary models are summarized, along with the arguments that strongly suggest that our universe is the product of inflation. The mechanisms that lead to eternal inflation in both new and chaotic models are described. Although the infinity of pocket universes produced by eternal inflation are unobservable, it is argued that eternal inflation has real consequences in terms of the way that predictions are extracted from theoretical models. The ambiguities in defining probabilities in eternally inflating spacetimes are reviewed, with emphasis on the youngness paradox that results from a synchronous gauge regularization technique. Vilenkin's proposal for avoiding these problems is also discussed.

27 pages, including 5 figures, LaTeX (elsart macros for Physics Reports, included). To be published in the David Schramm Memorial Volume of Physics Reports

Cited by in corpus (185)

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• Flux Compactification
• Inflationary paradigm in trouble after Planck2013
• The Black Hole Singularity in AdS/CFT
• The scaling evolution of cosmological constant
• Quantum Compositeness of Gravity: Black Holes, AdS and Inflation
• What does inflation really predict?
• Les Houches Lectures on Constructing String Vacua
• Probabilities in the inflationary multiverse
• Inflationary paradigm after Planck 2013
• Topology and the Cosmic Microwave Background
• Inflationary Cosmology: Exploring the Universe from the Smallest to the Largest Scales
• A Generalization to the Rastall Theory and Cosmic Eras
• The Cosmological Constant and the String Landscape
• Inflationary schism after Planck2013
• Boltzmann brains and the scale-factor cutoff measure of the multiverse
• Computational complexity of the landscape I
• A Holographic Framework for Eternal Inflation
• Variable gravity: A suitable framework for quintessential inflation
• Matter Bounce Loop Quantum Cosmology from $F(R)$ Gravity
• Predicting the cosmological constant with the scale-factor cutoff measure
• On the stability of the anomaly-induced inflation
• Quintessential inflation with canonical and noncanonical scalar fields and Planck 2015 results
• Properties of the scale factor measure
• Cosmology With Many Light Scalar Fields: Stochastic Inflation and Loop Corrections
• Spontaneous Inflation and the Origin of the Arrow of Time
• A Framework for the Landscape
• Multiple Inflation, Cosmic String Networks and the String Landscape
• Life at the Interface of Particle Physics and String Theory
• Quasi Single Field Inflation in the non-perturbative regime
• Unification of inflation and dark energy {\it à la} quintessential inflation
• Probabilities in the Bousso-Polchinski multiverse
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• Black Holes, Information, and Hilbert Space for Quantum Gravity
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• Boltzmann babies in the proper time measure
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• Stars In Other Universes: Stellar structure with different fundamental constants
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• What can the observation of nonzero curvature tell us?
• The Cold Big-Bang Cosmology as a Counter-example to Several Anthropic Arguments
• Counting Pockets with World Lines in Eternal Inflation
• Return of the Boltzmann Brains
• Multiple universes, cosmic coincidences, and other dark matters
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• The Degree of Fine-Tuning in our Universe -- and Others
• Relaxing the Cosmological Moduli Problem by Low-scale Inflation
• Stationary Measure in the Multiverse
• Many worlds in one
• Scale-invariant perturbations in ekpyrotic cosmologies without fine-tuning of initial conditions
• The Born Rule Dies
• Deformed Density Matrix and Generalized Uncertainty Relation in Thermodynamics
• Cycles in the Multiverse
• Hadronic signals of deconfinement at RHIC
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• Preventing eternality in phantom inflation
• Eternal Hilltop Inflation
• Cosmological Measures without Volume Weighting
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• Observable effects of anisotropic bubble nucleation
• Effective equations in quantum cosmology
• Moduli Entrapment with Primordial Black Holes
• Predictions from Star Formation in the Multiverse
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• Stochastic Axion Dark Matter in Axion Landscape
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• The Static Quantum Multiverse
• Dynamics of M-theory vacua
• The distribution of Omega_k from the scale-factor cutoff measure
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• de Sitter Swampland Conjecture in String Field Inflation
• Deformed Density Matrix and Quantum Entropy of the Black Hole
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• Vacuum Energy as the Origin of the Gravitational Constant
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• TASI Lectures: Cosmology for String Theorists
• Quantum Mechanics of the Early Universe and its Limiting Transition
• Stochastic inflation with an extremely large number of $e$-folds
• Consciousness and the Quantum
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• QCD Axion Window and False Vacuum Higgs Inflation
• Irreversible Processes in Inflationary Cosmological Models
• Small cosmological constant from a peculiar inflaton potential
• Is Trans-Planckian Censorship a Swampland Conjecture?
• The Cosmological Constant in the Quantum Multiverse
• Limitations of anthropic predictions for the cosmological constant $\Lambda$: Cosmic Heat Death of Anthropic Observers
• On the Habitability of Universes without Stable Deuterium
• Eternal Inflation, Global Time Cutoff Measures, and a Probability Paradox
• Tunneling and propagation of vacuum bubbles on dynamical backgrounds
• Reheating-volume measure for random-walk inflation
• The fine-tuning problems of particle physics and anthropic mechanisms
• Nearly scale-invariant curvature modes from entropy perturbations during graceful exit
• The Early Universe as a Quantum Growing Network
• Symmetric-Bounce Quantum State of the Universe
• Implication of island for inflation and primordial perturbations
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• Reheating-volume measure in the landscape
• On making predictions in a multiverse: conundrums, dangers, and coincidences
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• The Density Matrix Deformation in Physics of the Early Universe and Some of its Implications
• Measures for a Transdimensional Multiverse
• Is asymptotically safe inflation eternal?
• Density matrix and dynamical aspects of Quantum Mechanics with Fundamental Length
• Angular correlations of causally-coherent primordial quantum perturbations
• Fubini instantons in curved space
• Dark matter and dark radiation from the early universe with a modulus coupled to the PQMSSM
• de Sitter Space Decay and Cosmological Constant Relaxation in Unimodular Gravity with Charged Membranes
• Agnesi Weighting for the Measure Problem of Cosmology
• Rejuvenating the hope of a swampland consistent inflated multiverse with tachyonic inflation in the high energy RS-II Braneworld
• No-Bang Quantum State of the Cosmos
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• Applications of an exact counting formula in the Bousso-Polchinski Landscape
• Schwinger-Keldysh mechanism in extended quasi single field inflation
• Hawking-Moss Tunneling in Noncommutative Eternal Inflation
• Exploring a simple sector of the Einstein-Maxwell landscape
• Intermediate Scale Supersymmetric Inflation, Matter and Dark Energy
• Fundamental Length,Deformed Density Matrix and New View on the Black Hole Information Paradox
• Itô, Stratonovich, and zoom-in schemes in stochastic inflation
• Possible Anthropic Support for a Decaying Universe: A Cosmic Doomsday Argument
• $\alpha$-attractor potentials in loop quantum cosmology
• Breathing Comoving Hubble: Initial Condition and Eternity in view of the trans-Planckian Censorship Conjecture
• Inflation in String Field Theory
• On the necessity of phantom fields for solving the horizon problem in scalar cosmologies
• A geometric-probabilistic method for counting low-lying states in the Bousso-Polchinski Landscape
• Generalized Uncertainty Relations,Fundamental Length and Density Matrix
• New Local Duals in Eternal Inflation
• The Continuum of Discrete Trajectories in Eternal Inflation
• Further evidences for a generic Universe
• Consequences of moduli stabilization in the Einstein-Maxwell landscape
• Warm Ekpyrosis
• SuperCool Inflation: A Graceful Exit from Eternal Inflation at LHC Scales and Below
• How a Randall-Sundrum Brane-World Effective Potential Influences Inflation Physics
• Multiverse rate equation including bubble collisions
• A new paradigm for the dynamics of the early Universe
• Quantum Mechanics, Gravity, and the Multiverse
• Philosophical Implications of Inflationary Cosmology
• Cyclic completion of the anamorphic universe
• Suppression of the large scale curvature perturbation by interacting fluids
• Localization on the Landscape and Eternal Inflation
• Preliminary Inconclusive Hint of Evidence Against Optimal Fine Tuning of the Cosmological Constant for Maximizing the Fraction of Baryons Becoming Life
• Marginally Eternal Inflation
• Quantum Creation of Closed Universe with Both Effects of Tunneling and Well
• Getting inflationary models using the deformation method
• K-essential Phantom Energy: Doomsday around the Corner? Revisited
• Weyl Curvature Hypothesis in light of Quantum Backreaction at Cosmological Singularities or Bounces
• Cosmic Logic: a Computational Model
• Ex-nihilo II: Examination Syllabi and the Sequencing of Cosmology Education
• The Eternal Sunshine of the Spotless Mind
• Non-canonical scalar field in low anisotropy universe with intermediate inflation
• Can thermal input from a prior universe account for relic graviton production?
• The Quantum and Statistical Theory of Early Universe and Its Possible Applications to Cosmology
• The Level I Multiverse is not the same as the Level III Multiverse
• Falsifiability of Isolated Spacetime Regions
• Cosmological Implications of Thermodynamic Split Conjecture
• Planckian charged black holes and their cosmological ramifications
• Early inflation based on an aboriginal black hole
• Uniformity of Cosmic Microwave Background as a Non-Inflationary Geometrical Effect