Quantum Gravity: a Progress Report

Abstract

The problem of reconciling general relativity and quantum theory has fascinated and bedeviled physicists for more than 70 years. Despite recent progress in string theory and loop quantum gravity, a complete solution remains out of reach. I review the status of the continuing effort to quantize gravity, emphasizing the underlying conceptual issues and the various attempts to come to grips with them.

72 pages, 5 figures; review solicited by Reports on Progress in Physics, http://www.iop.org/Journals/RoPP

References in corpus (2)

• Self-Interaction and Gauge Invariance
• Gravitation and quantummechanical localization of macroobjects

Cited by in corpus (222)

• Lorentz invariance with an invariant energy scale
• Analogue Gravity
• Quantum Spacetime Phenomenology
• Generalized Lorentz invariance with an invariant energy scale
• Gravity's Rainbow
• Dilaton Gravity in Two Dimensions
• Doubly Special Relativity
• New varying speed of light theories
• Problem of Time in Quantum Gravity
• The Phoenix Project: Master Constraint Programme for Loop Quantum Gravity
• Is Quantum Gravity Necessary?
• Perturbative Quantum Gravity and its Relation to Gauge Theory
• Graviton propagator from background-independent quantum gravity
• Spacetime geometry from algebra: spin foam models for non-perturbative quantum gravity
• Loop quantum gravity: an outside view
• Quantum Gravity in 2+1 Dimensions: The Case of a Closed Universe
• Corrections to Schwarzschild Solution in Noncommutative Gauge Theory of Gravity
• Time and Tachyon
• Can We See Lorentz-Violating Vector Fields in the CMB?
• Hilbert Space Structures on the Solution Space of Klein-Gordon Type Evolution Equations
• Passing through the bounce in the ekpyrotic models
• Interacting classical and quantum ensembles
• Phenomenology of Doubly Special Relativity
• Quantum-Gravity Phenomenology: Status and Prospects
• How Far Are We from the Quantum Theory of Gravity?
• Quantum Mechanics of Klein-Gordon-Type Fields and Quantum Cosmology
• Possible astrophysical probes of quantum gravity
• Noncommutative Self-dual Gravity
• Do black holes radiate?
• Quantum mechanics: Myths and facts
• Emergence of helicity +/- 2 modes (gravitons) from qubit models
• Naturalness and Dimensional Transmutation in Classically Scale-Invariant Gravity
• Beables/Observables in Classical and Quantum Gravity
• A First Class Constraint Generates Not a Gauge Transformation, But a Bad Physical Change: The Case of Electromagnetism
• Limit on graviton mass from galaxy cluster Abell 1689
• Exponential fading to white of black holes in quantum gravity
• Quantum Gravity: A Brief History of Ideas and Some Prospects
• Interface of Gravitational and Quantum Realms
• Problem of Time and Background Independence: the Individual Facets
• Black Hole Thermodynamics and Statistical Mechanics
• Loop Quantum Gravity
• Spacetime foam: a review
• Constraints on rainbow gravity functions from black hole thermodynamics
• Generalized Uncertainty Principle Impact on Nonextensive Black Hole Thermodynamics
• Gravity as a field theory in flat space-time
• From the Embedding Theory to General Relativity in a result of inflation
• Time-Dependent Hilbert Spaces, Geometric Phases, and General Covariance in Quantum Mechanics
• Particles in Loop Quantum Gravity formalism: a thermodynamical description
• Group velocity in noncommutative spacetime
• Post-Newtonian gravitational effects in quantum interferometry
• Relational Particle Models. I. Reconciliation with standard classical and quantum theory
• Induced Gravity II: Grand Unification
• Timelike surfaces in Lorentz covariant loop gravity and spin foam models
• Model Comparison tests of modified gravity from the Eöt-Wash experiment
• Entropy of Killing horizons from Virasoro algebra in D-dimensional extended Gauss-Bonnet gravity
• Hypersurface foliation approach to renormalization of ADM formulation of gravity
• Introduction to Quantum-Gravity Phenomenology
• Gravitational Effects in Quantum Mechanics
• Gauge invariances vis-{á}-vis Diffeomorphisms in second order metric gravity: A new Hamiltonian approach
• Implications of Spacetime Quantization for the Bahcall-Waxman Neutrino Bound
• Non-commutative relativistic spacetimes and worldlines from 2+1 quantum (anti-)de Sitter groups
• Lagrangian constraints and renormalization of 4D gravity
• Approaching the Problem of Time with a Combined Semiclassical-Records-Histories Scheme
• ADM-like Hamiltonian formulation of gravity in the teleparallel geometry
• Equivalence principle and HBAR entropy of an atom falling into a quantum corrected black hole
• Kinematic quantum states for the Teleparallel Equivalent of General Relativity
• Equation of State of the Transplanckian Dark Energy and the Coincidence Problem
• Doubly-Special Relativity from Quantum Cellular Automata
• Foliation, jet bundle and quantization of Einstein gravity
• One-loop renormalization of a gravity-scalar system
• Experimental Demonstration that No Tripartite-Nonlocal Causal Theory Explains Nature's Correlations
• Cosmic string in gravity's rainbow
• Horizon Strings as 3d Black Hole Microstates
• Generalized uncertainty principle in resonant detectors of gravitational waves
• Rainbow black hole thermodynamics and the generalized uncertainty principle
• Black Holes in de Sitter Space: Masses, Energies and Entropy Bounds
• Thermodynamics of Reissner-Nordström Black Holes in Higher Dimensions: Rainbow Gravity Background With General Uncertainty Principle
• A note about the quantum of area in a non-commutative space
• Does gravity have to be quantized? Lessons from non-relativistic toy models
• Thermodynamics and remnants of Kiselev black holes in Rainbow gravity
• From Loop Space Mechanics to Nonabelian Strings
• Probing the generalized uncertainty principle through quantum noises in optomechanical systems
• Binding quantum matter and space-time, without romanticism
• Weak field reduction in teleparallel coframe gravity. Vacuum case
• Single-photon interference over 8.4 km urban atmosphere: towards testing quantum effects in curved spacetime with photons
• Covariance and Time Regained in Canonical General Relativity
• Path integral action of a particle with the generalized uncertainty principle and correspondence with noncommutativity
• Near horizon aspects (and beyond) of acceleration radiation of an atom falling into a large class of static spherically symmetric black hole geometries
• Testing a varying-$\Lambda$ model for dark energy within Co-varying Physical Couplings framework
• Spontaneous Dimensional Reduction?
• Quantum corrections to the thermodynamics of rotating charged BTZ black hole in gravity's rainbow
• Quantum measurement and quantum gravity : many-worlds or collapse of the wave-function?
• From physical symmetries to emergent gauge symmetries
• The Self-Organized de Sitter Universe
• Black holes and thermodynamics - The first half century
• The Most Probable Size of the Universe
• Minimal spatio-temporal extent of events, neutrinos, and the cosmological constant problem
• Anomalous particle-production thresholds through systematic and non-systematic quantum-gravity effects
• Path integral action in the generalized uncertainty principle framework
• GUP and Point Interaction
• An approach to classical quantum field theory based on the geometry of locally conformally flat space-time
• Why do elementary particles have such strange mass ratios? -- The role of quantum gravity at low energies
• Structure of Correlated Worldline Theories of Quantum Gravity
• A Local Resolution of the Problem of Time. IV. Quantum outline and piecemeal Conclusion
• Stochastic Einstein equations with fluctuating volume
• FLRW Cosmology with Horava-Lifshitz Gravity: Impacts of Equations of State
• Screening the graviton background, graviton pairing, and Newtonian gravity
• A new Doubly Special Relativity theory from a quantum Weyl-Poincare algebra
• Using CMB data to constrain non-isotropic Planck-scale modifications to Electrodynamics
• Quantum theory and the structure of space-time
• Gravitational interaction through a feedback mechanism
• Variables suitable for constructing quantum states for the Teleparallel Equivalent of General Relativity II
• Foliation-based quantization and black hole information
• Continuum interpretation of the dynamical-triangulation formulation of quantum Einstein gravity
• Emergent gauge symmetries: Yang-Mills theory
• Quantum astrometric observables II: time delay in linearized quantum gravity
• Space-time from collapse of the wave-function
• Quantum widening of CDT universe
• DDF and Pohlmeyer invariants of (super)string
• Which quantum theory must be reconciled with gravity? (And what does it mean for black holes?)
• Generalized uncertainty principle and $D$-dimensional quantum mechanics
• Variables suitable for constructing quantum states for the Teleparallel Equivalent of General Relativity I
• Predictive description of Planck-scale-induced spacetime fuzziness
• Complementarity-Entanglement Tradeoff in Quantum Gravity
• Breakdown of Lorentz Invariance for Spin-1/2 Particle Motion in Curved Space-Time with Applications to Muon Decay
• A causal perspective on random geometry
• Knot theory and a physical state of quantum gravity
• A model of quantum gravity with emergent spacetime
• Foliation-based approach to quantum gravity and applications to astrophysics
• Energy and angular momentum of general 4-dimensional stationary axi-symmetric spacetime in teleparallel geometry
• Emergent gravity: the BEC paradigm
• New 'phase' of quantum gravity
• Orientifolded Locally AdS3 Geometries
• Higher-order gravity in higher dimensions: Geometrical origins of four-dimensional cosmology?
• Challenges for Emergent Gravity
• Nonlinear quantum gravity on the constant mean curvature foliation
• External time canonical formalism for gravity in terms of embedding theory
• On skew tau-functions in higher spin theory
• Surface embedding, topology and dualization for spin networks
• Appearing Out of Nowhere: The Emergence of Spacetime in Quantum Gravity
• Topological Characterization of Higher Dimensional Charged Taub-NUT Instantons
• Path integral action for a resonant detector of gravitational waves in the generalized uncertainty principle framework
• Towards conformal loop quantum gravity
• Effective $f(R)$ actions for modified Loop Quantum Cosmologies via order reduction
• Cosmology of Vacuum
• Possibility of detecting gravity of an object frozen in a spatial superposition by the Zeno effect
• Correlated Worldline theory: Structure and Consistency
• Quantum gravity as an emergent phenomenon
• Hidden sl(2,R) Symmetry in 2D CFTs and the Wave Function of 3D Quantum Gravity
• Minimal length scale correction in the noise of gravitons
• Effective models of quantum gravity induced by Planck scale modifications in the covariant quantum algebra
• Correlations between emission events in Rainbow Gravity
• Rainbow Rindler metric and Unruh effect
• Quantum signatures from Horava-Lifshitz cosmography
• Propagators in the Correlated Worldline Theory of Quantum Gravity
• Quantum Entanglement with Generalized Uncertainty Principle
• Algebra of Implicitly Defined Constraints for Gravity as the General Form of Embedding Theory
• Unspeakables and the Epistemological path towards Quantum Gravity
• A primer on the ekpyrotic scenario
• Thermodynamics of a Schwarzschild black hole surrounded by quintessence in the generalized uncertainty principle framework
• Perturbation theory in covariant canonical quantization
• Rényi and von Neumann entropies of thermal state in Generalized Uncertainty Principle-corrected harmonic oscillator
• Resonant detectors of gravitational wave in the linear and quadratic generalized uncertainty principle framework
• Quantum Gravity from the Composition of Spacetime Constructed through Generalised Proper Time
• Teleparallel dark energy in a nonflat universe
• Cardy-Verlinde entropy in Hořava-Lifshitz gravity
• The Unruh effect and oscillating neutrinos
• Space and time as a consequence of GRW quantum jumps
• Field-Theoretical Formulation of Regge-Teitelboim Gravity
• In-in correlators and scattering amplitudes on a causal set
• Quantum Topology Change and Large N Gauge Theories
• Light-cone fluctuations and the renormalized stress tensor of a massless scalar field
• In Search of Fundamental Discreteness in 2+1 Dimensional Quantum Gravity
• An Analysis of States in the Phase Space: From Quantum Mechanics to General Relativity
• Planck scale effect on the thermodynamics of photon gas
• Quantum Mechanics without spacetime V - Why a quantum theory of gravity should be non-linear-
• Probes for String-Inspired Foam, Lorentz, and CPT Violations in Astrophysics
• Quantum Cosmology Aspects Of D3 Branes and Tachyon Dynamics
• A nonlinear quantum model of the Friedmann universe
• Friedmann cosmology in Regge-Teitelboim gravity
• Exact path integrals on half-line in quantum cosmology with a fluid clock and aspects of operator ordering ambiguity
• Quantum nonlocality, and the end of classical space-time
• How to approach Quantum Gravity - Background independence in 1+1 dimensions
• Quantum Gravito-Optics: A Light Route from Semiclassical Gravity to Quantum Gravity
• Canonical formulation of embedding gravity in a form of General Relativity with dark matter
• Gravity and the Superposition Principle
• Gravity's weight on worldline fuzziness
• Particle Creation from Vacuum by Lorentz Violation
• Deformations of anti-de Sitter black holes
• Quantum Mechanics from General Relativity and the Quantum Friedmann Equation
• A new approach for nonrelativistic bosonic string in flat space time
• Quasi-Local 3D Quantum Gravity : Exact Amplitude and Holography
• Manifestly covariant canonical quantization of gravity and diffeomorphism anomalies in four dimensions
• A Realist Interpretation of Unitarity in Quantum Gravity
• Quantum Gravity from Simplices: Analytical Investigations of Causal Dynamical Triangulations
• Incompleteness Theorems for Observables in General Relativity
• Manifestly covariant canonical quantization III: Gravity, locality, and diffeomorphism anomalies in four dimensions
• Nonlinear quantum mechanics, the superposition principle, and the quantum measurement problem
• Probing modified gravitational-wave dispersion with bursts from eccentric black-hole binaries
• Numerical Evaluation of the Causal Set Propagator in 2D Anti-de Sitter Spacetime
• Noncommutative Topological Half-flat Gravity
• An improved derivation of minimum information quantum gravity
• A fine quantum mechanism of classical gravity
• Earthquake Quantization
• Signatures of quantum geometry from exponential corrections to the black hole entropy
• Quantum Jet Theory I: Free fields
• Cosmological Casimir effect with maximum planckian momentum and accelerating universe
• Ergodic Concepts for a Self-Organizing Trivalent Spin Network: A Path to $(2+1)$-dimensional Black Hole Entropy
• Is spacetime quantum?
• Beyond general relativity: gravitational waves in non-minimally coupled theories
• Thermodynamic formulation of Cotton gravity in the Codazzi parametrization
• Quantum Dyanmics of Loop Quantum Gravity
• The Lagrangian of charged test particle in Horava-Lifshitz black hole and deformed phase space
• de Sitter Entanglement and Conformal Description of the Cosmological Horizon
• Making the case for causal dynamical triangulations
• Effects of quantum corrections to Lorentzian vacuum transitions in the presence of gravity
• Toward a mechanism for the emergence of gravity
• Explicit isometric embeddings of black holes geometry with non-singular matter distribution
• Topological discretization of bosonic strings
• Aharonov-Bohm-Like Scattering in the Generalized Uncertainty Principle-corrected Quantum Mechanics
• Time paradox in Quantum Gravity
• Huygens-Fresnel Principle in Superspace