SciPost Physics

SciPost Phys. 8, 058 (2020) · published 16 April 2020

• doi: 10.21468/SciPostPhys.8.4.058
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Abstract

We conjecture that, in a renormalizable effective quantum field theory where the heaviest stable particle has mass $m$, there are no bound states with radius below $1/m$ (Bound State Conjecture). We are motivated by the (scalar) Weak Gravity Conjecture, which can be read as a statement forbidding certain bound states. As we discuss, versions for uncharged particles and their generalizations have shortcomings. This leads us to the suggestion that one should only constrain rather than exclude bound objects. In the gravitational case, the resulting conjecture takes the sharp form of forbidding the adiabatic construction of black holes smaller than $1/m$. But this minimal bound-state radius remains non-trivial as $M_\text{P}\to \infty$, leading us to suspect a feature of QFT rather than a quantum gravity constraint. We find support in a number of examples which we analyze at a parametric level.

• Bošković et al., Soliton boson stars, Q-balls and the causal Buchdahl bound
  J. Cosmol. Astropart. Phys. 2022, 032 (2022) [Crossref]
• van Beest et al., Lectures on the Swampland Program in String Compactifications
  Physics Reports 989, 1 (2022) [Crossref]
• Espinosa et al., Tunneling potential approach to Q -balls
  Phys. Rev. D 108, 056019 (2023) [Crossref]
• Benakli et al., Dilatonic (Anti-)de Sitter black holes and Weak Gravity Conjecture
  J. High Energ. Phys. 2021, 58 (2021) [Crossref]
• Benakli et al., Revisiting the scalar weak gravity conjecture
  Eur. Phys. J. C 80, 742 (2020) [Crossref]
• Alonso-Álvarez et al., Leading logs in QCD axion effective field theory
  J. High Energ. Phys. 2021, 59 (2021) [Crossref]
• Calderón-Infante et al., The convex hull swampland distance conjecture and bounds on non-geodesics
  J. High Energ. Phys. 2021, 299 (2021) [Crossref]
• Heeck et al., Revisiting the Friedberg–Lee–Sirlin soliton model
  Eur. Phys. J. C 83, 526 (2023) [Crossref]
• Etheredge, Dense geodesics, tower alignment, and the Sharpened Distance Conjecture
  J. High Energ. Phys. 2024, 122 (2024) [Crossref]
• Heeck et al., Q -balls in polynomial potentials
  Phys. Rev. D 107, 016006 (2023) [Crossref]
• Ansari et al., Q -balls in the sky
  Phys. Rev. D 109, 023003 (2024) [Crossref]
• Palti, Fermions and the Swampland
  Physics Letters B 808, 135617 135617 (2020) [Crossref]
• Etheredge et al., Running decompactification, sliding towers, and the distance conjecture
  J. High Energ. Phys. 2023, 182 (2023) [Crossref]
• Del Grosso et al., Fermion soliton stars
  Phys. Rev. D 108, 044024 (2023) [Crossref]
• Kaplan et al., Closed strings and weak gravity from higher-spin causality
  J. High Energ. Phys. 2021, 145 (2021) [Crossref]
• Andriolo et al., Self-binding energies in AdS
  J. High Energ. Phys. 2023, 78 (2023) [Crossref]