The String landscape, black holes and gravity as the weakest force

By N. Arkani-Hamed, L. Motl, Alberto Nicolis, C. Vafa. 2006

1,372 citations recorded by the source corpus.

We conjecture a general upper bound on the strength of gravity relative to gauge forces in quantum gravity. This implies, in particular, that in a four-dimensional theory with gravity and a U(1) gauge field with gauge coupling g, there is a new ultraviolet scale Λ = gMPl, invisible to the low-energy effective field theorist, which sets a cutoff on the validity of the effective theory. Moreover, there is some light charged particle with mass smaller than or equal to Λ. The bound is motivated by arguments involving holography and absence of remnants, the (in) stability of black holes as well as the non-existence of global symmetries in string theory. A sharp form of the conjecture is that there are always light ``elementary'' electric and magnetic objects with a mass/charge ratio smaller than the corresponding ratio for macroscopic extremal black holes, allowing extremal black holes to decay. This conjecture is supported by a number of non-trivial examples in string theory. It implies the necessary presence of new physics beneath the Planck scale, not far from the GUT scale, and explains why some apparently natural models of inflation resist an embedding in string theory.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/f66f76700a8fe93f93c6a522666ff06c968179d0

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. Eran Palti
2. R. Myers
3. Gary Shiu
4. D. Baumann
5. E. Pajer
6. Liam McAllister
7. Tom Rudelius
8. M. Graña

In Nuclear and High Energy Physics

1. Eran Palti
2. R. Myers
3. Gary Shiu
4. D. Baumann
5. David Simmons-Duffin
6. Tom Rudelius
7. M. Graña
8. Frederik Denef

In Statistical and Nonlinear Physics

1. R. Myers
2. Eran Palti
3. Frederik Denef
4. L. Susskind
5. D. Harlow
6. Daniel A. Roberts
7. M. Graña
8. Gary Shiu

Citations in the corpus

• Electron stars for holographic metallic criticality (2010, neutral): “is stage whether all zero temperature charged AdS black holes with a nite size horizon are unstable [34]. If they are, this fact may be closely tied up with a version of the ‘weak gravity’ conjecture [35]. The instabilities lead to a new zero temperature bulk geometry, often without a nite size hori”
• Higher-order corrections to mass-charge relation of extremal black holes (2006, neutral): “Keywords: Black Holes in String Theory, Superstring Vacua, Black Holes. c© SISSA 2007 http://jhep.sissa.it/archive/papers/jhep122007068/jhep122007068.pdf J H E P 1 2 ( 2 0 0 7 ) 0 6 8 Contents”
• Holographic Complexity Equals Bulk Action? (2015, background): “General arguments have been given in this direction based on the weak-gravity conjecture [24], and several explicit examples are known, including superconducting condensation of charged fields [25–27] (such fields are typically present in UV completions of Eq.”
• Recent Progress in the Physics of Axions and Axion-Like Particles (2020, background): “On one hand, it is argued that quantum gravity provides a non-trivial lower bound on axion couplings [25], which might be in conflict with the requirement in some models of inflation for trans-Planckian axion field excursions [26–30].”
• Bouncing Cosmologies: Progress and Problems (2016, neutral): “[173] for a discussion of this problem).”
• The Shear Viscosity to Entropy Ratio: A Status Report (2011, background): “For instance, as suggested in [46], there might be a connection between the signs of the higher derivative couplings required to satisfy the weak gravity conjecture of [68] and that violating the shear viscosity to entropy bound.”
• Transplanckian axions!? (2015, methodology): “(2.3) The WGC would demand the existence of charged particles with a charge-to mass ratio smaller than that of the above extremal black holes, for any values of (Q1, Q2).”
• A review of axion inflation in the era of Planck (2013, background): “Discussions on how these bounds could have a more fundamental origin are given in [10].”
• Causality, analyticity and an IR obstruction to UV completion (2006, background): “There is also an interesting connection between our constraint on the DGP model and the “weak gravity” conjecture of [9].”
• Generalized flux vacua (2006, positive): “Whether this question is best resolved by a top-down (landscape [41]) approach of attempting to characterize the most general structure of string theory compactifications, or by a bottom-up (swampland [24, 42 ]) approach of understanding which four-dimensional theories have”
• Early dark energy does not restore cosmological concordance (2020, neutral): “13 that the distribution of axion decay constants is highly peaked at f ∼ Mpl, in stark contrast with theory expectations, both from statistical arguments (Halverson et al. (2019)), and the Weak Gravity Conjecture (Arkani-Hamed et al. (2007)); see, e.g., Rudelius (2015b).”
• GUTs and exceptional branes in F-theory — II. Experimental predictions (2008, background): “In fact, such a small value is already in conflict with the conjecture that gravity is the weakest force [70].”