From the Black Hole Conundrum to the Structure of Quantum Gravity

Abstract

We portray the structure of quantum gravity emerging from recent progress in understanding the quantum mechanics of an evaporating black hole. Quantum gravity admits two different descriptions, based on Euclidean gravitational path integral and a unitarily evolving holographic quantum system, which appear to present vastly different pictures under the existence of a black hole. Nevertheless, these two descriptions are physically equivalent. Various issues of black hole physics---including the existence of the interior, unitarity of the evolution, the puzzle of too large interior volume, and the ensemble nature seen in certain calculations---are addressed very differently in the two descriptions, still leading to the same physical conclusions. The perspective of quantum gravity developed here is expected to have broader implications beyond black hole physics, especially for the cosmology of the eternally inflating multiverse.

arXiv comment27 pages, 13 figures; invited "brief review" article. arXiv admin note: text overlap with arXiv:2010.15827

References in corpus (72)

• The Large N Limit of Superconformal Field Theories and Supergravity
• Holographic Derivation of Entanglement Entropy from AdS/CFT
• The World as a Hologram
• A bound on chaos
• A Covariant Holographic Entanglement Entropy Proposal
• The holographic principle
• Eternal Black Holes in AdS
• Black Holes: Complementarity or Firewalls?
• Black holes as mirrors: quantum information in random subsystems
• Cool horizons for entangled black holes
• Information in Black Hole Radiation
• Fast Scramblers
• The Stretched Horizon and Black Hole Complementarity
• The information paradox: A pedagogical introduction
• Replica Wormholes and the Entropy of Hawking Radiation
• Symmetries and Strings in Field Theory and Gravity
• Quantum Extremal Surfaces: Holographic Entanglement Entropy beyond the Classical Regime
• Quantum corrections to holographic entanglement entropy
• The entropy of bulk quantum fields and the entanglement wedge of an evaporating black hole
• The Page curve of Hawking radiation from semiclassical geometry
• The entropy of Hawking radiation
• Dimensional Reduction in Quantum Gravity
• An Apologia for Firewalls
• An Infalling Observer in AdS/CFT
• Transcending the ensemble: baby universes, spacetime wormholes, and the order and disorder of black hole information
• State-Dependent Bulk-Boundary Maps and Black Hole Complementarity
• Gauge/Gravity Duality and the Black Hole Interior
• Entanglement islands in higher dimensions
• Constraints on symmetry from holography
• Objective properties from subjective quantum states: Environment as a witness
• Quantum Darwinism: Entanglement, branches, and the emergent classicality of redundantly stored quantum information
• Islands outside the horizon
• JT gravity as a matrix integral
• Information radiation in BCFT models of black holes
• Hawking radiation, the Stefan-Boltzmann law, and unitarization
• Black Hole Complementarity vs. Locality
• Gedanken Experiments involving Black Holes
• Random Statistics of OPE Coefficients and Euclidean Wormholes
• Islands in Schwarzschild black holes
• Black hole information, unitarity, and nonlocality
• Page Curve for an Evaporating Black Hole
• Islands in Asymptotically Flat 2D Gravity
• The Multiverse Interpretation of Quantum Mechanics
• Black Hole Entanglement and Quantum Error Correction
• Comments on the Necessity and Implications of State-Dependence in the Black Hole Interior
• Local Operators in the Eternal Black Hole
• Eigenstate Thermalization and Disorder Averaging in Gravity
• How big is a black hole?
• Black Hole Horizons and Complementarity
• Global symmetry, Euclidean gravity, and the black hole information problem
• Physical Theories, Eternal Inflation, and Quantum Universe
• Frozen Vacuum
• Baby Universes, Holography, and the Swampland
• Page Curve and the Information Paradox in Flat Space
• On the volume inside old black holes
• Violations of the Born rule in cool state-dependent horizons
• Pulling the Boundary into the Bulk
• Bulk reconstruction and the Hartle-Hawking wavefunction
• Spacetime and Universal Soft Modes --- Black Holes and Beyond
• Ensemble from Coarse Graining: Reconstructing the Interior of an Evaporating Black Hole
• Branches of the Black Hole Wave Function Need Not Contain Firewalls
• The Black Hole Interior in Quantum Gravity
• The Static Quantum Multiverse
• A Note on (No) Firewalls: The Entropy Argument
• Behind the Horizon in AdS/CFT
• Gravity and Quantum Theory: Domains of Conflict and Contact
• Reanalyzing an Evaporating Black Hole
• Black Hole Interior in Unitary Gauge Construction
• Coarse-Graining Holographic States: A Semiclassical Flow in General Spacetimes
• The Interior of a Unitarily Evaporating Black Hole
• Qubit Transport Model for Unitary Black Hole Evaporation without Firewalls
• Shenanigans at the black hole horizon: pair creation or Boulware accretion?

Cited by in corpus (9)

• An Information Paradox and Its Resolution in de Sitter Holography
• Entanglement Phase Structure of a Holographic BCFT in a Black Hole Background
• Island for Gravitationally Prepared State and Pseudo Entanglement Wedge
• Axioms for retrodiction: achieving time-reversal symmetry with a prior
• Black Hole Interior in Unitary Gauge Construction
• The Multiverse in an Inverted Island
• Hints of Gravitational Ergodicity: Berry's Ensemble and the Universality of the Semi-Classical Page Curve
• Black Hole and de Sitter Microstructures from a Semiclassical Perspective
• Entropy of Radiation with Dynamical Gravity