Fermions and the Swampland

Abstract

In this note we consider whether there could be Swampland constraints associated to the presence of fermions in the theory. We propose that any fermion must couple to an infinite tower of states, and that the mass scale of this tower, in Planck units, is set by the strength of the Yukawa coupling to the tower. This is a type of fermionic version of the (magnetic) Weak Gravity Conjecture. We also find that supersymmetry plays a natural part in this fermionic realisation, which motivates a further proposal that supersymmetry can only be broken below the scale set by this Yukawa coupling. We perform some preliminary checks in string theory of these ideas.

arXiv comment8 pages. v2: Typos corrected, published version

References in corpus (32)

• The String Landscape, Black Holes and Gravity as the Weakest Force
• On the Geometry of the String Landscape and the Swampland
• Systematics of Moduli Stabilisation in Calabi-Yau Flux Compactifications
• The Swampland: Introduction and Review
• N-flation
• Black Holes and Large N Species Solution to the Hierarchy Problem
• Thermal production of gravitinos
• Wormholes, Emergent Gauge Fields, and the Weak Gravity Conjecture
• Entropy Bounds and Black Hole Remnants
• Super-Planckian Spatial Field Variations and Quantum Gravity
• The Weak Gravity Conjecture and Scalar Fields
• Evidence for a Lattice Weak Gravity Conjecture
• Emergence and the Swampland Conjectures
• A Stringy Test of the Scalar Weak Gravity Conjecture
• The Weak Gravity Conjecture in three dimensions
• Scales of Gravity
• A Tower Weak Gravity Conjecture from Infrared Consistency
• Infinite Distance Networks in Field Space and Charge Orbits
• The Swampland Distance Conjecture for Kahler moduli
• Backreacted Axion Field Ranges in String Theory
• The Origin of Spontaneous Symmetry Breaking in Theories with Large Extra Dimensions
• The Weak Gravity Conjecture and Emergence from an Ultraviolet Cutoff
• Large-N bounds on, and compositeness limit of, gauge and gravitational interactions
• Towards a Non-Supersymmetric String Phenomenology
• Modular Invariance, Finiteness, and Misaligned Supersymmetry: New Constraints on the Numbers of Physical String States
• Kahler Potentials of Chiral Matter Fields for Calabi-Yau String Compactifications
• Swampland Variations on a Theme by KKLT
• Evaporation of Microscopic Black Holes in String Theory and the Bound on Species
• A Spin-2 Conjecture on the Swampland
• On the weak gravity conjecture in string theory with broken supersymmetry
• A Conjecture on the Minimal Size of Bound States
• Setting the Stage for a Non-Supersymmetric UV-Complete String Phenomenology

Cited by in corpus (9)

• The Emergence Proposal in Quantum Gravity and the Species Scale
• The Gravitino and the Swampland
• A Gravitino Distance Conjecture
• Towards a Swampland Global Symmetry Conjecture using Weak Gravity
• On TCS $G_2$ manifolds and 4D Emergent Strings
• Misaligned Supersymmetry and Open Strings
• Uplift and towers of states in warped throat
• Hitchhiker's Guide to the Swampland: The Cosmologist's Handbook to the string-theoretical Swampland Programme
• Bounds on tower mass scales in the presence of throats of different warping