Spacetime foam: a review

Abstract

More than 65 years ago, John Wheeler suggested that quantum uncertainties of the metric would be of order one at the Planck scale, leading to large fluctuations in spacetime geometry and topology, which he termed "spacetime foam." In this review I discuss various attempts to implement this idea and to test it, both theoretically and, to a lesser extent, observationally.

42 pages (including 15 pages of referdences); v2: mainly more references, minor fixes; v3: corrected error on growth of triangulations, new discussion of higher order action, some other new references and clarifications

References in corpus (31)

• A Short Review of Loop Quantum Gravity
• MICROSCOPE mission: final results of the test of the Equivalence Principle
• A new framework for analyzing the effects of small scale inhomogeneities in cosmology
• Euclidean Wormholes in String Theory
• Observables, gravitational dressing, and obstructions to locality and subsystems
• Dimension and Dimensional Reduction in Quantum Gravity
• Non-Paradoxical Loss of Information in Black Hole Evaporation in a Quantum Collapse Model
• Measurement of Quantum Fluctuations in Geometry
• Probability distributions for quantum stress tensors in four dimensions
• Vacuum Fluctuations and the Small Scale Structure of Spacetime
• Wormholes without averaging
• The Holometer: An Instrument to Probe Planckian Quantum Geometry
• New Constraints on Quantum Gravity from X-ray and Gamma-Ray Observations
• Gluing Initial Data Sets for General Relativity
• Describing the platycosms
• Zeta Function Methods and Quantum Fluctuations
• CPT Violation and Decoherence in Quantum Gravity
• A survey of Einstein metrics on 4-manifolds
• Einstein metrics and the number of smooth structures on a four-manifold
• Designer de Sitter Spacetimes
• Wormholes, a fluctuating cosmological constant and the Coleman mechanism
• Quantum Stress Tensor Fluctuations and their Physical Effects
• Detectability of Planck-Scale-Induced Blurring with Gamma-Ray Bursts
• The Omega Effect as a Discriminant for Space-Time Foam
• Six Lectures on Four 4-Manifolds
• Continued fractions and Einstein manifolds of infinite topological type
• What does Birkhoff's theorem really tell us?
• Light incoherence due to background space fluctuations
• The world problem: on the computability of the topology of 4-manifolds
• Cosmic searches for Lorentz invariance violation
• Can gravitational microlensing by vacuum fluctuations be observed?

Cited by in corpus (11)

• Promise of Future Searches for Cosmic Topology
• Searching for Decoherence from Quantum Gravity at the IceCube South Pole Neutrino Observatory
• Causal structure and topology change in (2+1)-dimensional simplicial gravity
• Probing Lorentz invariance with a high-energy neutrino flare
• Spacetime Foam Effects on Charged AdS Black Hole Thermodynamics
• No Flavor Anisotropy in the High-Energy Neutrino Sky Upholds Lorentz Invariance
• Quantum Field Theory on Multifractal Spacetime: Varying Dimension and Ultraviolet Completeness
• Quantum scalar field propagator in a stochastic gravitational plane wave
• Foundational aspects of spinor structures and exotic spinors
• Signatures of Correlation of Spacetime Fluctuations in Laser Interferometers
• A Brief Thermodynamic Study For Four Dimensional Einstein Gauss Bonnet Black Holes Using Fractalised Barrow Entropy