An Introduction to the Weak Gravity Conjecture

Abstract

The Weak Gravity Conjecture holds that gravity must be the weakest force. This is true of the familiar forces in our own universe -- electromagnetism, for instance, is many orders of magnitude stronger than gravity. But the bold claim of the Weak Gravity Conjecture is that this statement is true, not only for electromagnetism in our universe, but for any similar force in any consistent universe governed by quantum mechanics. In this brief introduction, aimed at advanced undergraduates or beginning graduate students, we elaborate on the precise definition of the Weak Gravity Conjecture, the evidence for it, and some of the remarkable implications of it. We explain how the Weak Gravity Conjecture may play a role in bridging the gulf between the formal mathematics of string theory and the real-world observations of particle physics and cosmology.

arXiv comment27 pages, 7 figures, invited review, published in Contemporary Physics

References in corpus (33)

• String Theory Dynamics In Various Dimensions
• The String Landscape, Black Holes and Gravity as the Weakest Force
• On the Geometry of the String Landscape and the Swampland
• Completing Natural Inflation
• N-flation
• On the Possibility of Large Axion Decay Constants
• Tensionless Strings and the Weak Gravity Conjecture
• Naturalness and the Weak Gravity Conjecture
• The Weak Gravity Conjecture and Scalar Fields
• Higher-order corrections to mass-charge relation of extremal black holes
• Evidence for a Lattice Weak Gravity Conjecture
• Transplanckian axions !?
• Sharpening the Weak Gravity Conjecture with Dimensional Reduction
• Proof of the Weak Gravity Conjecture from Black Hole Entropy
• The Weak Gravity Conjecture: A Review
• Planckian Axions and the Weak Gravity Conjecture
• Euclidean wormholes, baby universes, and their impact on particle physics and cosmology
• Testing the Weak Gravity -- Cosmic Censorship Connection
• Weak Gravity Strongly Constrains Large-Field Axion Inflation
• On the Possibility of Large Axion Moduli Spaces
• Repulsive Forces and the Weak Gravity Conjecture
• Constraints on Axion Inflation from the Weak Gravity Conjecture
• On Axionic Field Ranges, Loopholes and the Weak Gravity Conjecture
• Violating weak cosmic censorship in AdS${}_4$
• Modular Fluxes, Elliptic Genera, and Weak Gravity Conjectures in Four Dimensions
• Evidence for an Electrifying Violation of Cosmic Censorship
• Quantum Corrections in 4d N=1 Infinite Distance Limits and the Weak Gravity Conjecture
• Large-Field Inflation with Multiple Axions and the Weak Gravity Conjecture
• Can Gravitational Instantons Really Constrain Axion Inflation?
• Duality and Axionic Weak Gravity
• Systematics of Axion Inflation in Calabi-Yau Hypersurfaces
• A Holographic Argument for the Penrose Inequality in AdS
• Moduli Space Reconstruction and Weak Gravity

Cited by in corpus (5)

• Mutual Influence of Photon Sphere and Non-Commutative Parameter in Various Non-Commutative Black Holes: Part I- Towards evidence for WGC
• WGC as WCCC protector: The Synergistic Effects of various Parameters in Identifying WGC candidate Models
• Assessing WGC Compatibility in ModMax Black Holes via Photon Spheres Analysis and WCCC Validation
• Hitchhiker's Guide to the Swampland: The Cosmologist's Handbook to the string-theoretical Swampland Programme
• Coherent electrically-charged quantum black holes