Luis E. Ibáñez
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Moduli Self-Fixing Open
In Quantum Gravity (QG), large moduli values lead to towers of exponentially light states, making the QG cut-off field-dependent. In 4D supersymmetric (SUSY) theories, this cut-off is set by the species scale $Λ(z_i, \bar{z}_i)$, where $z_…
Laplacians in Various Dimensions and the Swampland Open
The species cutoff is a moduli-dependent quantity signaling the onset of quantum gravitational phenomena, whose form can be oftentimes determined from higher-derivative and higher-curvature corrections within low-energy gravitational EFTs.…
Modular invariant Starobinsky inflation and the Species Scale Open
A bstract Potentials in cosmological inflation often involve scalars with trans-Planckian ranges. As a result, towers of states become massless and their presence pushes the fundamental scale not to coincide with M P but rather with the sp…
On small Dirac neutrino masses in string theory Open
A bstract We study how tiny Dirac neutrino masses consistent with experimental constraints can arise in string theory SM-like vacua. We use as a laboratory 4d $$ \mathcal{N} $$ = 1 type IIA Calabi-Yau orientifold compactifications, and in …
On the species scale, modular invariance and the gravitational EFT expansion Open
A bstract The concept of the species scale as the quantum gravity cut-off has been recently emphasised in the context of the Swampland program. Along these lines, we continue the quest for a precise understanding of its role within effecti…
Modular Invariant Starobinsky Inflation and the Species Scale Open
Potentials in cosmological inflation often involve scalars with trans-Planckian ranges. As a result, towers of states become massless and their presence pushes the fundamental scale not to coincide with $M_{\rm P}$ but rather with the $spe…
On small Dirac Neutrino Masses in String Theory Open
We study how tiny Dirac neutrino masses consistent with experimental constraints can arise in string theory SM-like vacua. We use as a laboratory 4d ${\cal N}=1$ type IIA Calabi--Yau orientifold compactifications, and in particular recent …
Yukawa Couplings at Infinite Distance and Swampland Towers in Chiral Theories Open
We study limits of vanishing Yukawa couplings of 4d chiral matter fields in Quantum Gravity, using as a laboratory type IIA orientifolds with D6-branes. In these theories chiral fermions arise at brane intersections, where an infinite towe…
On the Species Scale, Modular Invariance and the Gravitational EFT expansion Open
The concept of the species scale as the quantum gravity cut-off has been recently emphasised in the context of the Swampland program. Along these lines, we continue the quest for a precise understanding of its role within effective field t…
Entropy Bounds and the Species Scale Distance Conjecture Open
The Swampland Distance Conjecture (SDC) states that, as we move towards an infinite distance point in moduli space, a tower of states becomes exponentially light with the geodesic distance in any consistent theory of Quantum Gravity. Altho…
Towers and Hierarchies in the Standard Model from Emergence in Quantum Gravity Open
Based on Quantum Gravity arguments, it has been suggested that all kinetic terms of light particles below the UV cut-off could arise in the IR via quantum (loop) corrections. These loop corrections involve infinite towers of states becomin…
The Emergence Proposal in Quantum Gravity and the Species Scale Open
In the Emergence Proposal in QG it is conjectured that all light-particle kinetic terms are absent in the fundamental UV theory and are generated by quantum corrections in the IR. It has been argued that this may provide for some microscop…
IR/UV mixing, towers of species and swampland conjectures Open
A bstract By applying the Covariant Entropy Bound (CEB) to an EFT in a box of size 1 / ΛIR one obtains that the UV and IR cut-offs of the EFT are necessarily correlated. We argue that in a theory of Quantum Gravity (QG) one should identify…
Swampland constraints on neutrino masses Open
A bstract Compactifying the Standard Model (SM) on a circle may lead to AdS 3D vacua, depending on the character (Majorana or Dirac) and the mass of the lightest neutrino. It has been shown that, imposing the Ooguri-Vafa conjecture that no…
IR/UV Mixing, Towers of Species and Swampland Conjectures Open
By applying the Covariant Entropy Bound (CEB) to an EFT in a box of size $1/Λ_{\text{IR}}$ one obtains that the UV and IR cut-offs of the EFT are necessarily correlated. We argue that in a theory of Quantum Gravity (QG) one should identify…
AdS swampland conjectures and light fermions Open
We consider constraints on $D$-dimensional theories in $M_D$, $dS_D$ and $AdS_D$ backgrounds in the light of AdS swampland conjectures as applied to their compactification in a circle. In particular we consider the non-SUSY AdS instability…
A gravitino distance conjecture Open
A bstract We conjecture that in a consistent supergravity theory with non-vanishing gravitino mass, the limit m 3 / 2 → 0 is at infinite distance. In particular one can write M tower ~ $$ {m}_{3/2}^{\delta } $$ so that as the gravitino mas…
A Gravitino Distance Conjecture Open
We conjecture that in a consistent supergravity theory with non-vanishing gravitino mass, the limit $m_{3/2}\rightarrow 0$ is at infinite distance. In particular one can write $M_{\mathrm{tower}} \sim m_{3/2}^δ$ so that as the gravitino ma…
Constraining the EW Hierarchy from the Weak Gravity Conjecture Open
In this addendum we complement the remarks made in ref[1] constraining the value of the cosmological constant $Λ_4$ in terms of neutrino masses. Those were based on a sharpened version of the Weak Gravity Conjecture as applied to compactif…
Higgs-otic inflation and moduli stabilization Open
We study closed-string moduli stabilization in Higgs-otic inflation in Type\nIIB orientifold backgrounds with fluxes. In this setup large-field inflation is\ndriven by the vacuum energy of mobile D7-branes. Imaginary selfdual (ISD)\nthree-…
An axion-induced SM/MSSM Higgs landscape and the Weak Gravity Conjecture Open
We construct models in which the SM Higgs mass scans in a landscape. This is achieved by coupling the SM to a monodromy axion field through Minkowski 3-forms. The Higgs mass scans with steps given by delta(m_H^2)= eta mu f, where mu and f …