The authors reformulate the equations of motion for AdS_D × I solutions in axio-dilaton gravity as a first-order autonomous dynamical system, identify fixed points and analytic solutions for arbitrary D including in type IIB, and discuss numerical flows in massive IIA.
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The Swampland: Introduction and Review
Canonical reference. 100% of citing Pith papers cite this work as background.
abstract
The Swampland program aims to distinguish effective theories which can be completed into quantum gravity in the ultraviolet from those which cannot. This article forms an introduction to the field, assuming only a knowledge of quantum field theory and general relativity. It also forms a comprehensive review, covering the range of ideas that are part of the field, from the Weak Gravity Conjecture, through compactifications of String Theory, to the de Sitter conjecture.
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The Schwinger integral over light towers captures precisely the instantons with actions in the window (Λ_sp/M_light)^{-1} ≤ S_inst ≤ Λ_sp/M_light, as verified in eight- and seven-dimensional toroidal compactifications.
In codimension-one warped compactifications with exponential potentials, the KK mass decay rate λ_KK is reduced by warping but still satisfies the Sharpened Distance Conjecture precisely when the higher-dimensional potential obeys the Strong de Sitter condition.
All integrable 2D Horndeski theories (and thus many regular black-hole metrics) arise as spherical reductions of pure d≥4 gravities, which the paper terms quasi-topological.
RG-improved black hole spacetimes with scale-dependent gravitational coupling are derived as vacuum solutions to 2D Horndeski master field equations, embedding prior works and exposing implementation discrepancies.
Defines IR-finite amplitudes M_E that preserve analyticity and unitarity to derive positivity bounds on EFTs including electromagnetism and gravity in D=4.
Explicit scale-separated dS5 maximum in M-theory on a 6D Riemann-flat manifold with vacuum energy 10^{-8} in Planck units, obtained via Casimir energies and fluxes.
Causal sets can approximate black hole horizons via discrete timelike curves and ladders tracing null geodesics, with a discrete expansion changing sign across the horizon in a 1+1D toy model.
Optimal transport yields a generalized Wasserstein distance on field space, obtained from a WKB expansion of a Schrödinger equation and extended to dynamical gravity via the Wheeler-DeWitt equation in the ADM formalism.
Imaginary wormholes and the IDB imply that towers of BPS EFT instantons generate infinitely many superpotential terms that break non-invertible axion shift symmetries in N=1 axiverse models.
New analytic AdS9 solutions in type IIB with finite action and central charge, numerical massive IIA solutions with diverging action, and perturbative dS9 solutions are constructed in type II supergravities.
Using weight polytopes of irreducible representations, a finite list of symmetric moduli spaces satisfies the SDC decay rates; most embed from an E8(8) EFT but three cannot be obtained from string or M-theory compactifications.
Proposes a refinement of the Swampland Cobordism Conjecture for duality groups, arguing that diverging commutator widths necessitate infinitely many duality defects to realize monodromies in 9d supergravity bordisms.
Proposes phase-resolved invariant path-length criteria and a master formula for lower bound on ε_ek in ekpyrotic cosmologies, using BKL suppression and conversion windows as constraints.
UV completeness in scalar-tensor gravity restricts Yukawa fifth-force parameters α and λ to a finite wedge whose complement is ruled out, with part of the excluded domain below current experimental bounds.
Six-dimensional primordial black holes with memory burden effects can survive as light dark matter in a two-extra-dimension model at the 10 TeV scale, producing high-multiplicity thermal events at future colliders.
Refines charge quantization via homotopy type A whose homotopy groups classify brane charges and homology groups classify higher-form symmetries, deriving swampland-like constraints that rule out noncompact gauge groups and non-nilpotent Lie algebras for field strengths.
Five-dimensional rotating primordial black holes with initial masses above 10^10 grams survive to today and can account for all dark matter due to suppressed Hawking radiation and memory burden effects in the micron-scale dark dimension.
In asymptotically safe gravity, dimension-five couplings of ultralight scalar dark matter to gauge field strengths vanish and are not generated perturbatively.
Morse-Bott inequalities yield homology bounds and topology-change counts for generic cobordisms to nothing in string theory compactifications.
Derives WGC bound on probe charge-to-mass ratio from positivity of anomalous dimensions in dual CFT for charged particles in higher-derivative AdS black holes, with bound increasing with couplings and ISCOs existing up to the bound.
A sampling-based bootstrap for graviton poles in EFTs yields non-projective bounds that fix the EFT cutoff scale relative to the Planck mass, with M/M_P ≲ 7.8 in D=5.
An analytic bound on axion parameters in thawing quintessence is derived independently of initial conditions and used with cosmological observations plus quantum gravity constraints to exclude large regions of axion dark energy parameter space.
Under the Gravitino Conjecture, only one or two large extra dimensions are compatible with a linear scaling between gravitino mass and KK scale in Type II compactifications, implying light gravitino and gauge-mediated breaking for micron-sized dimensions.
citing papers explorer
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$\text{AdS}_D\times I$ solutions in axio-dilaton gravity
The authors reformulate the equations of motion for AdS_D × I solutions in axio-dilaton gravity as a first-order autonomous dynamical system, identify fixed points and analytic solutions for arbitrary D including in type IIB, and discuss numerical flows in massive IIA.
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Taxonomy of Instanton Corrections in Infinite Distance Limits
The Schwinger integral over light towers captures precisely the instantons with actions in the window (Λ_sp/M_light)^{-1} ≤ S_inst ≤ Λ_sp/M_light, as verified in eight- and seven-dimensional toroidal compactifications.
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Alice in Warpland: KK modes, Warped Compactifications and the Swampland
In codimension-one warped compactifications with exponential potentials, the KK mass decay rate λ_KK is reduced by warping but still satisfies the Sharpened Distance Conjecture precisely when the higher-dimensional potential obeys the Strong de Sitter condition.
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All $2D$ generalised dilaton theories from $d\geq 4$ gravities
All integrable 2D Horndeski theories (and thus many regular black-hole metrics) arise as spherical reductions of pure d≥4 gravities, which the paper terms quasi-topological.
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Effective geometrodynamics for renormalization-group improved black-hole spacetimes in spherical symmetry
RG-improved black hole spacetimes with scale-dependent gravitational coupling are derived as vacuum solutions to 2D Horndeski master field equations, embedding prior works and exposing implementation discrepancies.
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Positivity with Long-Range Interactions
Defines IR-finite amplitudes M_E that preserve analyticity and unitarity to derive positivity bounds on EFTs including electromagnetism and gravity in D=4.
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An M-theory dS maximum from Casimir energies on Riemann-flat manifolds
Explicit scale-separated dS5 maximum in M-theory on a 6D Riemann-flat manifold with vacuum energy 10^{-8} in Planck units, obtained via Casimir energies and fluxes.
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Towards black-hole horizons and geodesic focusing in causal sets
Causal sets can approximate black hole horizons via discrete timelike curves and ladders tracing null geodesics, with a discrete expansion changing sign across the horizon in a 1+1D toy model.
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Optimal paths across potentials on scalar field space
Optimal transport yields a generalized Wasserstein distance on field space, obtained from a WKB expansion of a Schrödinger equation and extended to dynamical gravity via the Wheeler-DeWitt equation in the ADM formalism.
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Non-invertible symmetries in the axiverse, and the imaginary wormholes
Imaginary wormholes and the IDB imply that towers of BPS EFT instantons generate infinitely many superpotential terms that break non-invertible axion shift symmetries in N=1 axiverse models.
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AdS$_9$ solutions in type II supergravities
New analytic AdS9 solutions in type IIB with finite action and central charge, numerical massive IIA solutions with diverging action, and perturbative dS9 solutions are constructed in type II supergravities.
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EFTs with Symmetric Moduli Spaces: the Landscape and the Swampland
Using weight polytopes of irreducible representations, a finite list of symmetric moduli spaces satisfies the SDC decay rates; most embed from an E8(8) EFT but three cannot be obtained from string or M-theory compactifications.
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Bordisms between 9d type IIB supergravities and commutator widths of duality groups
Proposes a refinement of the Swampland Cobordism Conjecture for duality groups, arguing that diverging commutator widths necessitate infinitely many duality defects to realize monodromies in 9d supergravity bordisms.
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Phase-resolved field-space distance criteria in ekpyrotic, bouncing and cyclic cosmologies
Proposes phase-resolved invariant path-length criteria and a master formula for lower bound on ε_ek in ekpyrotic cosmologies, using BKL suppression and conversion windows as constraints.
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Fifth-Force Constraints from UV-Complete Scalar-Tensor Gravity
UV completeness in scalar-tensor gravity restricts Yukawa fifth-force parameters α and λ to a finite wedge whose complement is ruled out, with part of the excluded domain below current experimental bounds.
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Micron-sized Extra Dimensions and Primordial Black Holes: Charged, Rotating, and Memory Burdened
Six-dimensional primordial black holes with memory burden effects can survive as light dark matter in a two-extra-dimension model at the 10 TeV scale, producing high-multiplicity thermal events at future colliders.
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Generalised Symmetries and Swampland-Type Constraints from Charge Quantisation via Rational Homotopy Theory
Refines charge quantization via homotopy type A whose homotopy groups classify brane charges and homology groups classify higher-form symmetries, deriving swampland-like constraints that rule out noncompact gauge groups and non-nilpotent Lie algebras for field strengths.
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5D Rotating Black Holes as dark matter in Dark Dimension Scenario: Hawking Radiation versus the Memory Burden Effect
Five-dimensional rotating primordial black holes with initial masses above 10^10 grams survive to today and can account for all dark matter due to suppressed Hawking radiation and memory burden effects in the micron-scale dark dimension.
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Towards theory constraints on ultralight dark matter from quantum gravity
In asymptotically safe gravity, dimension-five couplings of ultralight scalar dark matter to gauge field strengths vanish and are not generated perturbatively.
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Morse-Bott inequalities, Topology Change and Cobordisms to Nothing
Morse-Bott inequalities yield homology bounds and topology-change counts for generic cobordisms to nothing in string theory compactifications.
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ISCOs and the weak gravity conjecture bound in higher derivative theories of gravity
Derives WGC bound on probe charge-to-mass ratio from positivity of anomalous dimensions in dual CFT for charged particles in higher-derivative AdS black holes, with bound increasing with couplings and ISCOs existing up to the bound.
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Sampling the Graviton Pole and Deprojecting the Swampland
A sampling-based bootstrap for graviton poles in EFTs yields non-projective bounds that fix the EFT cutoff scale relative to the Planck mass, with M/M_P ≲ 7.8 in D=5.
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Bounding axion dark energy
An analytic bound on axion parameters in thawing quintessence is derived independently of initial conditions and used with cosmological observations plus quantum gravity constraints to exclude large regions of axion dark energy parameter space.
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Supersymmetry, Large Extra Dimensions and the Gravitino Conjecture
Under the Gravitino Conjecture, only one or two large extra dimensions are compatible with a linear scaling between gravitino mass and KK scale in Type II compactifications, implying light gravitino and gauge-mediated breaking for micron-sized dimensions.
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Sharpening the Supersymmetric Axion Weak Gravity Conjecture
The paper verifies the bound fS/|n| ≤ (π/(2 κ_d)) sqrt((d-1)/(d-2)) for axion instantons and sharpens it to fS/|n| ≤ (1/κ_4) sqrt(7/2) for supersymmetric 4d instantons using three approaches in the string landscape.
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Bounds on Discrete Gauge Symmetries in Supergravity
Upper bounds are placed on the order of enhanced discrete gauge symmetries in supersymmetric supergravity theories with 8 or more supercharges, with some bounds saturated by string theory examples.
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Towards the Realization of the Dark Dimension Scenario in Ho\v{r}ava-Witten Theory
Hořava-Witten theory offers a potential string embedding of the dark dimension by localizing the Standard Model on the 11th interval, with symmetric tadpole cancellation and an infinite-distance limit helping derive the scalar potential and couplings from Schwinger integrals.
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Some Properties and Uses of the Species Scale
The Species Scale implies Laplace eigenvalue equations for BPS-protected Wilson coefficients and produces a one-loop moduli potential with minima at desert points that may stabilize Kähler moduli in 4d Type IIB orientifolds.
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Stochastic Survival near Swampland Boundaries
Surviving inflationary histories develop a universal inward drift near any hard swampland boundary — two times the diffusion over the distance to the edge — regardless of the cutoff's microscopic origin.
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Barrow holographic dark energy interacting model in the presence of radiation and matter
Numerical study of interacting Barrow holographic dark energy in non-flat universes with radiation, showing EoS transitions and higher fitted H0 values that may address Hubble tension.
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Assisted Fibre Inflation in Perturbative LVS
Multi-field fibre inflation in perturbative LVS uses collective dynamics of several moduli to achieve viable cosmology with sub-Planckian individual field ranges given by total range divided by sqrt(n).
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What to do with a Ricci-flat Calabi--Yau metric?
Numerical Ricci-flat Calabi–Yau metrics turn string compactifications from topological existence statements into computable geometries, unlocking normalized couplings, spectra, and metric-level tests of mirror symmetry.
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The weak gravity conjecture in perturbative strings
A summary of a proposed proof that the Weak Gravity Conjecture follows from the structure of perturbative bosonic string theory.
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Rethinking quantum information in gravity and fields
The paper organizes important open questions in quantum gravity and quantum information into four themes without presenting new results or derivations.
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Breaking Free from the Swampland of Impossible Universes through the DESI Portal
A review of string-inspired dynamical dark energy models claiming compatibility with DESI's hints of evolving dark energy under swampland constraints.
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Dark energy from string theory: an introductory review
String theory imposes constraints on dark energy but permits various construction attempts for de Sitter vacua and single-field exponential quintessence models despite obstructions.
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On Legacy of Starobinsky Inflation
A memorial review of the Starobinsky inflation model that proposes a deformation for primordial black hole production and discusses superstring quantum corrections plus universal reheating.
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ICTP Lectures on (Non-)Invertible Generalized Symmetries
Lecture notes explain non-invertible generalized symmetries in QFTs as topological defects arising from stacking with TQFTs and gauging diagonal symmetries, plus their action on charges and the SymTFT framework.
- Double fibration in G-theory and the cobordism conjecture