An invitation to loop quantum gravity

Abstract

We describe the basic assumptions and key results of loop quantum gravity, which is a background independent approach to quantum gravity. The emphasis is on the basic physical principles and how one deduces predictions from them, at a level suitable for physicsts in other areas such as string theory, cosmology, particle physics, astrophysics and condensed matter physics. No details are given, but references are provided to guide the interested reader to the literature. The present state of knowledge is summarized in a list of 35 key results on topics including the hamiltonian and path integral quantizations, coupling to matter, extensions to supergravity and higher dimensional theories, as well as applications to black holes, cosmology and Plank scale phenomenology. We describe the near term prospects for observational tests of quantum theories of gravity and the expectations that loop quantum gravity may provide predictions for their outcomes. Finally, we provide answers to frequently asked questions and a list of key open problems.

50 pages, to be submitted to Reviews of Modern Physics

References in corpus (20)

• Modern tests of Lorentz invariance
• Black hole evaporation: A paradigm
• Physical effects of the Immirzi parameter
• Quantum gravity with a positive cosmological constant
• Spectral Analysis of the Volume Operator in Loop Quantum Gravity
• Falsifiable predictions from semiclassical quantum gravity
• A Note On The Chern-Simons And Kodama Wavefunctions
• A topological model of composite preons
• On the superselection theory of the Weyl algebra for diffeomorphism invariant quantum gauge theories
• Topological M-theory as Unification of Form Theories of Gravity
• Symmetry and entropy of black hole horizons
• A Quantum Gravitational Relaxation of The Cosmological Constant
• Free vacuum for loop quantum gravity
• Gauge fixing in Causal Dynamical Triangulations
• A quantization of topological M theory
• Background Independent Quantum Field Theory and the Cosmological Constant Problem
• On the counting of black hole states in loop quantum gravity
• A statistical formalism of Causal Dynamical Triangulations
• Stringent limits on the existence of Planck time from stellar interferometry
• Leading Log Corrections to Bekenstein-Hawking Entropy

Cited by in corpus (79)

• Modern tests of Lorentz invariance
• Spectral Dimension of the Universe
• Flipped spinfoam vertex and loop gravity
• A glance beyond the quantum model
• Anomaly-free scalar perturbations with holonomy corrections in loop quantum cosmology
• Algebraic Quantum Gravity (AQG) I. Conceptual Setup
• Higher Derivative Quantum Gravity with Gauss-Bonnet Term
• Testing the Master Constraint Programme for Loop Quantum Gravity I. General Framework
• Loop quantization of spherically symmetric midi-superspaces
• Coherent spin-networks
• Falsifiable predictions from semiclassical quantum gravity
• Loop quantum gravity: the first twenty five years
• Disordered locality in loop quantum gravity states
• The String Landscape, the Swampland, and the Missing Corner
• Consistency Check on Volume and Triad Operator Quantisation in Loop Quantum Gravity II
• Consistency Check on Volume and Triad Operator Quantisation in Loop Quantum Gravity I
• On (Cosmological) Singularity Avoidance in Loop Quantum Gravity
• Testing the Master Constraint Programme for Loop Quantum Gravity II. Finite Dimensional Systems
• Gauge-invariant coherent states for Loop Quantum Gravity I: Abelian gauge groups
• Quantum gravity computers: On the theory of computation with indefinite causal structure
• Testing the Master Constraint Programme for Loop Quantum Gravity IV. Free Field Theories
• Semiclassical Mechanics of the Wigner 6j-Symbol
• Gauge-invariant coherent states for Loop Quantum Gravity II: Non-abelian gauge groups
• Relating loop quantum cosmology to loop quantum gravity: Symmetric sectors and embeddings
• Uniform discretizations: a new approach for the quantization of totally constrained systems
• Testing the Master Constraint Programme for Loop Quantum Gravity V. Interacting Field Theories
• Collider Signals of Gravitational Fixed Points
• Physical boundary Hilbert space and volume operator in the Lorentzian new spin-foam theory
• Critical Overview of Loops and Foams
• Large extra dimensions and small black holes at the LHC
• Background independent quantization and wave propagation
• The Holst Spin Foam Model via Cubulations
• Effective gravity from a quantum gauge theory in Euclidean space-time
• Background independent quantizations: the scalar field II
• Towards Gravity from the Quantum
• Scalar Field theory in $\kappa$-Minkowski spacetime from twist
• New directions in Background Independent Quantum Gravity
• Restricting Fourth Order Gravity via Cosmology
• Emergent Braided Matter of Quantum Geometry
• Thermodynamics in Loop Quantum Cosmology
• Testing Lorentz Invariance Violation in Quantum Gravity Theories
• Canonical path integral measures for Holst and Plebanski gravity. I. Reduced Phase Space Derivation
• Loop Quantum Gravity in Ashtekar and Lagrange-Finsler Variables and Fedosov Quantization of General Relativity
• One-loop effective action of the IKKT model for cosmological backgrounds
• A quantization of topological M theory
• Automorphisms in Loop Quantum Gravity
• Hypothesis on the Nature of Time
• Conserved Quantities in Background Independent Theories
• Quantum Cycle in Relativistic Non-Commutative Space with Generalized Uncertainty Principle correction
• Bibliography of Publications related to Classical Self-dual variables and Loop Quantum Gravity
• In Search of Quantum de Sitter Space: Generalizing the Kodama State
• Averaged null energy condition in Loop Quantum Cosmology
• Piecewise linear loop quantum gravity
• On the Classification of Asymptotic Quasinormal Frequencies for d-Dimensional Black Holes and Quantum Gravity
• Conformally Coupled General Relativity
• Loop Quantum Cosmology corrections on gravity waves produced during primordial inflation
• Comparing Quantum Gravity Models: String Theory, Loop Quantum Gravity, and Entanglement gravity versus $SU(\infty )$-QGR
• `Iconoclastic', Categorical Quantum Gravity
• New Black Holes Solutions in a Modified Gravity
• Oriented matroid theory and loop quantum gravity in (2+2) and eight dimensions
• Prolegomena to any future Quantum Gravity
• `Third' Quantization of Vacuum Einstein Gravity and Free Yang-Mills Theories
• Applications of the Gauge Principle to Gravitational Interactions
• Time evolution of a non-singular primordial black hole
• Building flat space-time from information exchange between quantum fluctuations
• Quantum gravity in the sky
• Stochastic Evolution of Graphs using Local Moves
• Quaternion-Loop Quantum Gravity
• Quantum Relativity: Physical Laws Must be Invariant Over Quantum Systems
• A black hole cast on a non-commutative background
• Loop quantum gravity and observations
• Expanding and Self-Organizing 2D Universe Models Emerging from Frozen Trivalent Spin Networks
• Aleph_null Hypergravity in Three-Dimensions
• Energy corrections due to the Non-commutative Phase-Space of the Charged Harmonic Oscillator in a constant magnetic field in 3D
• Holography in the EPRL Model
• Relativity for games
• Anti-de Sitter space from supersymmetric gauge theory
• Finitary-Algebraic `Resolution' of the Inner Schwarzschild Singularity
• Spin current in BF theory