String Phenomenology 2023

3 Jul 2023, 08:00 → 7 Jul 2023, 17:45 Asia/Seoul

Institute for Basic Science, Daejeon

Seung-Joo Lee, Pablo Soler

안녕하세요!

The 22nd edition of the String Phenomenology conference will be hosted by the Center for Theoretical Physics of the Universe (CTPU), at the Institute for Basic Science (IBS) in Daejeon, South Korea. The aim of the conference is to discuss the latest developments at the interface between string theory, particle physics and cosmology.

This event will be preceded by the CERN-Korea Workshop: "Recent trends in & out of the Swampland". Conference participants are most welcome to attend and can indicate their preference during the registration. 

Topics include:   

• Swampland and Quantum Gravity Conjectures
• String Model Building in Particle Physics and Cosmology
• Formal and Mathematical Aspects of String Compactifications
• Corners of the String Landscape (Heterotic, F-Theory, G2, Non-geometric,...)
• Machine Learning Techniques in the String Landscape

 

Invited speakers include:

• David Andriot  데이비드 
• Lakshya Bhardwaj  락샤
• Michele Cicoli  미켈레
• Mirjam Cvetič  미리암
• Alon Faraggi  알론
• Fotis Farakos  포티스
• Iñaki García-Etxebarría  이냐키
• Mariana Graña  마리아나
• James Gray  제임스
• Yuta Hamada  유타
• Arthur Hebecker  아터 
• Jonathan Heckman  조나단
• Ben Heidenreich  벤
• Yu-tin Huang  유틴
• Luis Ibáñez  루이스
• Sang Hui Im  상희
• Donghui Jeong  동희
• Tatsuo Kobayashi  탓수오 
• Sven Krippendorf  스벤
• Dieter Lüst  디터
• Severin Lüst  세베린

 

Organizers:   

• Stephen Angus  스티븐  (APCTP)
• Sanghyeon Chang  장상현  (IBS-CTPU)
• Kang Sin Choi  최강신  (Ewha)
• Kiwoon Choi  최기운  (IBS-CTPU)
• Jai-chan Hwang  황재찬  (IBS-CTPU)
• Seung-Joo Lee  이승주  (IBS-CTPU) - chair
• Sungjay Lee  이성재  (KIAS)
• Pablo Soler  파블로  (Oviedo/IBS-CTPU) - cochair
• Piljin Yi  이필진  (KIAS) 

 

Past conferences:

• 2022 - Liverpool
• 2021 - Northeastern (Virtual)
• 2020 - Northeastern (Virtual)
• 2019 - CERN
• 2018 - Warsaw
• 2017 - Blacksburg
• 2016 - Ioannina
• 2015 - Madrid
• ...

 

Supporting organizations:   

• IBS-CTPU 
• National Research Foundation of Korea  

 

 

• Andre Lukas  안드레
• Fernando Marchesano  페르난도
• Luca Martucci  루카
• Miguel Montero  미겔
• Jakob Moritz 야콥
• Hans-Peter Nilles  한스-피터
• Susha Parameswaran  수샤
• Fernando Quevedo  페르난도
• Stuart Raby  스튜아트
• Fabian Ruehle  파비안
• Marco Scalisi  마르코
• Lorenz Schlechter  로렌츠
• Gary Shiu  게리
• Irene Valenzuela  이레네
• Yi-Nan Wang  이난
• Timo Weigand  티모
• Alexander Westphal  알렉산더
• Max Wiesner  맥스 
• Timm Wrase  팀
• Ivonne Zavala  이보네

 

 

 

 

 

 

 

 

Program.pdf

Monday, 3 July

Opening Remarks

Plenary: 1

Convener: Liam McAllister

1 Challenges of Stringy de Sitter and Asymptotic Acceleration

I will review recent progress in the quantitative understanding of anti-D3-brane uplifts. One key aspect is the tension between the control over curvature corrections, the limited allowed tadpole contribution, and the need to keep the uplifting potential exponentially small. This encourages the study of a fine-tuned anti-D3-brane uplifting proposal that does NOT rely on extremely strong warping. In addition, I will present recent results on Asymptotic Cosmological Acceleration as a conceptual alternative to de Sitter.

Speaker: Arthur Hebecker

1 Hebecker.pdf

Recording

2 Scalar potentials from (classical) string theory

Characterising scalar potentials in quantum gravity EFTs is important for the swampland program and for the connection to cosmology. In this talk, we will discuss properties of these (positive or negative) scalar potentials in the bulk (critical points and their mass spectrum), in the asymptotics (tail slope) and the in between region (bump in the slope rate). For each region, we will comment on the options for valid cosmological scenarios.

Speaker: David Andriot

2 Andriot.pdf

Recording

3 Asymptotic limits in moduli space

The study of asymptotic limits in moduli space has received a lot of attention in recent years. The Strong dS Conjecture provides a testable prediction that can be potentially violated using multiple complex structure moduli in type IIB/F-theory compactifications. I present attempts to realize such a violation in explicit string theory compactifications without Kähler moduli. I will also discuss how the Strong dS Conjecture can potentially imply the Sharpened Distance Conjecture.

Speaker: Timm Wrase

3 Wrase.pdf

Recording

10:30 Coffee break

Plenary: 2

Convener: Ivonne Zavala

4 Late-time Attractors and Cosmic Acceleration

We investigate whether an accelerating universe can be realized as an asymptotic late-time solution of Friedmann–Lemaître–Robertson–Walker (FLRW) cosmology with multi-field multi-exponential potentials. Such potentials are commonly considered in models of dark energy, and at the same time describe the asymptotic regions of the moduli space of string theory. Late-time cosmological solutions exhibit a universal behavior which enables us to bound the rate of time variation of the Hubble parameter. This bound gives an immediate and analytic diagnostic of the fate of cosmic acceleration. Furthermore, we prove the conditions under which scaling cosmologies are inevitable late-time cosmological attractors of this general class of potentials, independently of initial conditions. As scaling solutions are known analytically, we can characterize late-time observables exactly. When applied to string-theory, our analytic knowledge of late-time cosmological solutions enables us to single out potentials that can describe an accelerating universe from those which cannot and to quantitatively test several conjectured Swampland criteria.

Speaker: Gary Shiu

4 Shiu.pdf

Recording

5 Quantum Gravity Constraints on Cosmic Acceleration

In this talk, I will discuss the implications of Swampland quantum gravity constraints on various aspects of cosmic acceleration. Specifically, based on the results of recent and ongoing work, I will show that the Swampland Distance Conjecture alone imposes a wide range of stringent limitations on both inflation and dark energy.

Speaker: Marco Scalisi

5 Scalisi.pdf

Recording

6 A non-perturbative test of the DGKT vacuum

I will present ongoing work with I. Valenzuela on consistency checks of the DGKT scenario coming from the dynamics of the D4-branes that mediate flux transitions and that parametrize the moduli space of the dual field theory

Speaker: Miguel Montero

6 Montero.pdf

Recording

12:30 Lunch

Plenary: 3

Convener: Arthur Hebecker

7 Heterotic de Sitter Beyond Modular Symmetry

We study the vacua of 4d heterotic toroidal orbifolds using effective theories consisting of an overall Kahler modulus, the dilaton, and non-perturbative corrections to both the superpotential and Ka ̈hler potential that respect modular invariance. We prove three de Sitter no-go theorems for several classes of vacua and thereby substantiate and extend previous conjectures. Additionally, we provide evidence that extrema of the scalar potential can occur inside the SL(2, Z) fundamental domain of the Kahler modulus, in contradiction of a separate conjecture. We also illustrate a loophole in the no-go theorems and determine criteria that allow for metastable de Sitter vacua. Next, we identify inherently stringy non-perturbative effects in the dilaton sector that could exploit this loophole and potentially realize de Sitter vacua. Finally, we move beyond the symmetric regime of a single overall Kahler modulus and treat the bulk moduli of a T^2-orbifold explicitly, driving us into the world of Sp(4,Z) Siegel modular forms.

Speaker: Alexander Westphal

7 Westphal.pdf

Recording

8 Minimal matter supergravity and asymmetric orbifold

Understanding the boundary between the Landscape and Swampland in supergravity theories is an important subject to study. This talk considers supergravity equal to or less than six dimensions. There are minimal matter supergravity theories that can not be obtained from geometric compactifications. We study the Landscape of the non-geometric asymmetric orbifold compactification to investigate whether such theories are realized.

Speaker: Yuta Hamada

8 Hamada.pdf

Recording

9 Goldstino Condensation

We discuss the formation of goldstino condensates in theories with spontaneously broken supersymmetry. Our analysis shows that the standard Volkov-Akulov model with a large number of non-linear supersymmetries develops an instability towards such a condensation.

Speaker: Fotis Farakos

9 Farakos.pdf

Recording

15:30 Coffee break

Plenary: 4

Convener: Mariana Grana

10 New Calabi-Yau Manifolds from Genetic Algorithms

Calabi–Yau manifolds can be obtained as hypersurfaces in toric varieties built from reflexive polytopes. We generate reflexive polytopes in various dimensions using a genetic algorithm. As a proof of principle, we demonstrate that our algorithm reproduces the full set of reflexive polytopes in two and three dimensions, and in four dimensions with a small number of vertices and points. Motivated by this result, we construct five-dimensional reflexive polytopes with the lowest number of vertices and points. By calculating the normal form of the polytopes, we establish that many of these are not in existing datasets and therefore give rise to new Calabi–Yau four-folds. In some instances, the Hodge numbers we compute are new as well.

Speaker: Andre Lukas

10 Lukas.pdf

11 A new perspective on flux vacua

Moduli stabilisation in string compactifications with many light scalars remains a major blind-spot in the string landscape. In these regimes, analytic methods cease to work for generic choices of UV parameters which is why numerical techniques have to be exploited. In this talk, I report on new numerical approaches to efficiently construct string vacua. Our approach heavily utilises automatic differentiation, just-in-time compilation and parallelisation features, to efficiently construct string vacua. I argue that this implementation provides a golden opportunity to efficiently analyse large unexplored regions of the string landscape. As a first example, I report on the application of our techniques to the search of Type IIB flux vacua in Calabi-Yau orientifold compactifications.

Speaker: Sven Krippendorf

11 Krippendorf.pdf

Recording

12 Massive string towers, level crossing, and black hole attractors

Using numerical approximations to the Ricci-flat CY metric, it has become possible to compute higher eigenmodes of the scalar Laplacian, which correspond to massive towers of states. It has been observed that these towers become heavier or lighter as one traverses the CY moduli space, and that eigenmodes cross along codimension 1 loci. This begs the question whether there is something special about these crossing points. To shed light on this, we study simple one-parameter families of CYs in various dimensions. For tori, analytic solutions are possible, which shows an interesting relation between level crossings and number theory. We also use these toy models to assess the quality and the main sources of error for of our numeric spectrum approximations. Armed with these results, we speculate about generalizations of our  observations to more general CY manifolds.

Speaker: Fabian Ruehle

12 Ruehle.pdf

Recording

18:00 Reception

Tuesday, 4 July

Plenary: 5

Convener: Kimyeong Lee

13 Generalized Symmetries, Gravity, and Topological Non-Decoupling

We discuss recent progress on using methods in topology to study questions in string compactification, with an eye towards applications in string phenomenology.

Speaker: Jonathan Heckman

1 Heckman.pdf

Recording

14 Generalized Charges of Symmetries

Generalized charges describe the possible actions of a global symmetry on operators of various dimensions in a quantum field theory. The global symmetry can be invertible or non-invertible. Understanding of these charges provides a stepping stone for physical applications of non-invertible symmetries. I will describe that generalized charges can be identified with topological operators of the Symmetry Topological Field Theory (SymTFT) associated to the symmetry. In some cases, the SymTFTs can be computed by using string theory or holography.

Speaker: Lakshya Bhardwaj

15 Tameness and Complexity in QFTs

In this talk I will introduce tameness as a generalized finiteness principle and explore its appearance in perturbative as well as non-perturbative quantum field theories. Several swampland conjectures regarding tameness are formulated and tested in solvable models. As an application the structures arising from tameness are used to create a well-defined notion of complexity.

Speaker: Lorenz Schlechter

3 Schlechter.pdf

Recording

10:30 Coffee break

Plenary: 6

Convener: Stuart Raby

16 The Taste of Flavor of (heterotic) string theory

Modular transformations of string theory are shown to play a crucial role in the discussion of discrete flavor symmetries in the Standard Model. They include CP transformations and provide a unification of CP with traditional flavor symmetries within the framework of the eclectic flavor scheme. The unified flavor group is non-universal in moduli space and exhibits the phenomenon of "Local Flavor Unification", where different sectors of the theory (like quarks and leptons) can be subject to different flavor structures.

Speaker: Hans Peter Nilles

4 Nilles.pdf

Recording

17 Modular weights of matter fields in LEEFT from type II string theory

I would like to discuss the modular weights of matter fields in magnetized D-brane models. Corrections due to localized magnetic fluxes are shown. Also, it will be shown that field theory with magnetic flux background has I would like to discuss the modular weights of matter fields in magnetized D-brane models. Corrections due to localized magnetic fluxes are shown. Also, it will be shown that field theory with magnetic flux background has OSp(1|2) algebra, that is, subaglegra of super-Virasoro algebra. I will discuss the correspondence between this field theory and 2D SCFT.

Speaker: Tatsuo Kobayashi

5 Kobayashi.pdf

Recording

18 Aspects of potential matching across heterotic transitions

The first part of this talk will review recent work describing a geometric process by which gauge bundles can traverse conifold transitions in heterotic theories. These transitions lead to seemingly dual heterotic compactifications, generalizing the (0,2) target space duality seen in GLSMs. The second part of this talk will describe ongoing work aimed at investigating whether this is a true duality, reflected for example in the potential structure of the theories, or merely a coincidental matching at the level of the massless spectrum.

Speaker: James Gray

6 Gray.pdf

Recording

12:30 Lunch

Parallel: Tue 1-A

Convener: Tatsuo Kobayashi

19 Upper bound on the Atiyah–Singer index from tadpole cancellation

I will discuss upper bounds on the generation number of chiral zero-modes in heterotic and Type II string theories. We find that tadpole cancellation conditions lead to the small generation number of quarks and leptons.

Speaker: Hajime Otsuka

1 Otsuka.pdf

20 Blow-up of magnetized T^2/Z_N and index theorem

The number of zero modes of magnetized T^2/Z_N orbifold have been obtained in previous paper. However, due to the existence of singularities in the orbifold, the Atiyah-Singer index theorem cannot be applied, and hence the physical/geometrical meaning of the zero mode number has not been clear. To apply the Atiyah-Singer to the model, we replace the T^2/Z_N orbifold by a smooth manifold without singularities, by cutting out the singularities of the magnetized T^2/Z_N orbifold and attaching smooth manifolds (part of S^2) to them. The Atiyah-Singer index theorem can be then applied directly to the smooth manifold to reveal the geometric interpretation of the number of zero modes.

Speaker: Maki Takeuchi

2 Takeuchi.pdf

21 Small Kinetic Mixing in String Theory

Kinetic mixing between gauge fields of different U(1) factors is a well-studied phenomenon in 4d EFT. In string compactifications with U(1)s from sequestered D-brane sectors, kinetic mixing becomes a key target for the UV prediction of a phenomenologically important EFT operator. Surprisingly, in many cases kinetic mixing is absent due to a non-trivial cancellation. In particular, D3-D3 kinetic mixing in type-IIB vanishes while D3-anti-D3 mixing does not. This follows both from exact CFT calculations on tori and as well as from a leading-order 10d supergravity analysis, where the key cancellation is between the C2 and B2 contribution. We take the latter approach, which is the only one available in realistic Calabi-Yau settings, to a higher level of precision by including sub-leading terms of the brane action and allowing for non-vanishing C0. The exact cancellation persists, which we argue to be the result of SL(2,R) self-duality. We note that a B2-C2 term on the D3-brane, which is often forgotten in the recent literature, is essential to obtain the correct zero result. Finally, allowing for SL(2,R)-breaking fluxes, kinetic mixing between D3-branes arises at a volume-suppressed level. We provide the basic explicit formulae, leaving the study of phenomenologically relevant, more complex situations for the future.

Speaker: Ruben Kuespert

3 Kuespert.pdf

22 Phenomenology in magnetized orbifold models

We consider magnetized orbifold models to realize three-generation structure, mass hierarchy in the Standard model. In particular, we focus on the theory compactified on six-dimensional orbifolds, not on two-dimensional ones.

Speaker: Shohei Takada

4 Takada.pdf

23 A dataset of R-symmetric Wess-Zumino models

We made an exhaustive search for generic R-symmetric Wess-Zumino models with up to 5 chiral fields, and checked the consistency of their vacuum solutions with predictions from the Nelson-Seiberg theorem and its generalization. Each model is recorded as the R-charge assignment of fields, which uniquely determines the cubic polynomial superpotentials with generic coefficients. The resulting model dataset can be used to estimate the accuracy of the field counting method for finding SUSY models in the string landscape. More applications are expected in future work.

Speaker: Zheng Sun

5 Sun.pdf

24 Meson scattering from string scattering in holographic QCD

We present a detailed study of the applications of holographic QCD to the scattering of mesons. The starting point is that mesons are described as strings in curved confining backgrounds. We show how, through holography, we can modernize the description of hadrons as strings, and how to approach meson scattering in the framework of holography.

Speaker: Dorin Weissman

6 Weissman.pdf

Parallel: Tue 1-B

Convener: Jonathan Heckman

25 Reflection 7-branes and how to use them

In this talk we argue for the existence of a non-supersymmetric 7-brane in type IIB superstring theory predicted by the Cobordism Conjecture. We also investigate their localized dynamics in terms of worldvolume fields as well as their role as charge conjugation operators.

Speaker: Markus Dierigl

1 Dierigl.pdf

26 The Branes Behind Generalized Symmetry Operators

By now it is well-known that the global symmetries of a quantum field theory (QFT) can be recast as the existence of certain extended topological operators. This reformulation has produced much progress in expanding the notion of symmetry, culminating in so-called categorical or generalized global symmetries. We review a systematic, non-Lagrangian construction of such symmetry operators for QFTs admitting an embedding into string theory. We argue that such symmetry operators can be constructed by wrapping (flux)branes on asymptotic cycles “at infinity” of the internal dimensions. In many cases the resulting symmetry operators exhibit non-invertible fusion laws and can be used to obtain insights into strongly-coupled physical phenomena.

Speaker: Max Huebner

2 Hubner.pdf

27 Back to Heterotic Little String Theories on ALE Spaces

I will revisit some aspects of Heterotic little strings on ALE spaces motivated by recent advances in understanding the structures of six-dimensional theories and their continuous 2-group symmetries. In particular, the construction of novel Heterotic E8 × E8 ALE instantonic theories through the 6d conformal matter approach are presented and therefore extend previous results explored by Aspinwall and Morrison as well as Blum and Intriligator. This results in the predictions of their T-dual partners via the match of the Coulomb branch dimension, flavor symmetries, and 2-group structure constants. The identification of dual Little String Theory(LST) is then confirmed through the geometric engineering in F-theory, where the T-dual system is realized as the inequivalent elliptic fibration structure of the same Calabi-Yau manifold. In the end, this architecture also inspires us to investigate the geometric engineering limit of heterotic strings on ALE spaces.

Speaker: Muyang Liu

3 Liu.pdf

28 Geometric Bounds on the 1-Form Gauge Sector

6D SUGRA theories give an interesting testing ground of our understanding of field theory condition and geometric String Landscape searches.
In this talk I discuss how we bound the global gauge group topology in 6D SUGRAs coupled to non-Abelian gauge symmetries which is dictated by a perturbative heterotic string. This allows to geometrically deduce, that the global gauge group topology must be embeddable into E8.

Speaker: Paul-Konstantin Oehlmann

4 Oehlmann.pdf

29 Towards a complete classification of 6D supergravities

The structure of 6D supergravity is very rigid; for example, supersymmetry and anomaly cancellation greatly constrain the possible choices for gauge group and matter content. The task of constructing consistent theories can be rephrased in terms of finding cliques with certain desirable properties in a multigraph built from simple building blocks. In this talk I will outline this strategy for classifying consistent theories and present partial results in its implementation.

Speaker: Gregory Loges

5 Loges.pdf

30 Aspects of string theory compactifications with non trivial torsional homology

The concept of integer homology naturally arises in string theory compactifications to implement flux quantization conditions. However, only the free part is usually considered. We recently discovered that if torsional homology is considered, a new natural interpretation of some massive KK modes with mass much lower than the KK scale arises. Using such description, we found that in some type 2 compactifications the 4d EFTs may have access to non-trivial topological information of the 6d internal manifold. More precisely, it is possible to extract the linking numbers from EFT data when a non-renormalization theorem for linking numbers holds. During the talk I will explicitly prove such a result in an example. The talk is meant to be complementary to the talk given by Fernando Marchesano.

Speaker: Matteo Zatti

6 Zatti.pdf

Parallel: Tue 1-C

Convener: Gary Shiu

31 Gravitational positivity bounds: implications for the swampland program

In the context without gravity, it has been known that the S-matrix positivity bounds offer a useful tool to derive ultraviolet constraints on low-energy effective field theories. In this talk, we assume that the positivity bounds are approximately valid even in the presence of gravity, and discuss the implications of the bounds for phenomenological models. Interestingly, we obtain nontrivial bounds on models in general, while the Standard Model easily satisfies the bounds. We also provide a scenario which gives rise to the approximate gravitational positivity bounds based on the Reggeization of graviton exchange.

Speaker: Junsei Tokuda

1 Tokuda.pdf

32 Gravitational Positivity Bounds on Dark Gauge Boson

Recently, bounds on parameter spaces of effective field theories derived from unitarity of scattering amplitudes have been under intense investigation. It is especially interesting to study the bounds on gravitational theories, as they bounds provide quantitative “swampland” constraints. These bound are referred to as gravitational positivity bounds.
In our research, we discuss the application of gravitational positivity bounds to the massive U(1) gauge boson in the Higgs/ St¨uckelberg mechanism. By making certain assumptions about gravitational amplitudes at high energy, we obtain a lower bound on the gauge boson mass as well as the gauge coupling.

Speaker: Sota Sato

2 Sato.pdf

33 Massive spin-2 particles and the swampland

The Classical Regge Growth (CRG) conjecture proposes that the S-matrix of any consistent classical theory never grows faster than s² at fixed t. In this talk, we will use this conjecture to impose constraints on theories containing massive spin-2 particles. We will consider the most general situation where the massive spin-2 can couple to a graviton, a spin-1 and a scalar particle. We will discuss if there is any such theory compatible with this requirement.

Speaker: Joan Quirant

3 Quirant.pdf

34 Gravitino dynamics and the Swampland

The gravitino is a fundamental element of any supergravity theory and it’s interesting to study how its dynamics affects string-inspired effective models with broken supersymmetry. When supersymmetry is realised nonlinearly, consistency problems arise, in the form of potential acausality and breakdown of the effective theory. In this talk I will discuss how such problems can be studied in terms of effective goldstino models by means of the equivalence theorem. On one hand, this strategy shows how the potential acausality survives in the effective theories with global supersymmetry, placing them into the swampland from the bottom-up point of view. On the other, it allows to define an improved supersymmetry breaking setup that both restores causality and parametrizes the EFT breakdown. Based on arXiv:2206.13451 and ongoing work.

Speaker: Gabriele Casagrande

4 Casagrande.pdf

35 AdS scale separation and the distance conjecture

It has been argued that orientifold vacua with fluxes in type IIA string theory can achieve moduli stabilisation and arbitrary decoupling between the AdS and KK scales upon sending certain unconstrained RR-flux quanta to infinity. In this talk, I discuss how a new scalar field in the open-string sector allows us to interpolate between such IIA vacua that differ in flux quanta. In the limit of large fluxes, the scalar field distance between the vacua is nicely consistent with the distance conjecture. This shows that the massive IIA vacua pass an important Swampland criterion and I discuss how this suggests that these scale-separated AdS vacua might not be in the Swampland.

Speaker: Vincent Van Hemelryck

5 Van Hemelryck.pdf

36 on/off scale separation

We discuss three-dimensional N=1 AdS flux vacua obtained from compactifications of massive type IIA on G2 holonomy spaces with O2/O6 planes. Similar AdS flux vacuum solutions with parametric scale separation and moduli stabilization have been studied before, however in this new solution, considering a different flux/brane ansatz we show that configurations that are scale-separated can be within finite distance from non-scale-separated ones, while both remain at large volume and weak coupling. More specifically, the transition from non-scale to scale-separated vacua is achieved with the use of a D4-brane modulus, which allows the F4 flux to jump, and has an effective potential always accessible to the three-dimensional low-energy theory. Finally, we show that our analysis allows us to check the distance conjecture, as we can track explicitly the masses of the KK modes.

Speaker: George Tringas

6 Tringas.pdf

15:30 Coffee break

Parallel: Tue 2-A

Convener: Fabian Ruehle

37 Axion-Photon Couplings in the String Landscape

In this talk, I will review the construction of an ensemble of axion models arising from type IIB string theory on toric hypersurface Calabi-Yau threefold orientifolds. I’ll explain some of the observational constraints on these string theory axions, coming from dark matter bounds as well as axion-photon coupling experiments. Finally, I’ll explain a mechanism that suppresses axion-photon couplings compared to naive estimates, and present some preliminary data on these couplings.

Speaker: Naomi Gendler

7 Gendler.pdf

38 Line bundle cohomology

The first part of the talk outlines the need for ultra-fast cohomology computations in heterotic model building. The second part presents some new results on line bundle cohomology on certain complex varieties of various dimensions and types (including Calabi-Yau threefolds), in particular in relation to generating functions.

Speaker: Andrei Constantin

8 Constantin.pdf

39 Decoding Nature with Nature's Tools

In this talk, I will present recent work (2306.03147) on engineering Heterotic Line Bundle realisations of the standard model via genetic algorithms and quantum annealing. We show that these methods are able to efficiently find almost all models within a given range of line bundles, and make use of recently discovered analytic formulae for line bundle cohomology to impose the exact spectrum requirements.

Speaker: Thomas Harvey

9 Harvey.pdf

40 How many Calabi-Yau manifolds are known? Placing upper and lower bounds on the Kreuzer-Skarke list.

We use Wall's theorem to find bounds on the number of Calabi-Yau manifolds in the Kreuzer-Skarke list for small Picard number. Lower bounds are found using polynomial invariant theory, as well as some further invariants descending from the integral nature of the topological data. A range of computational techniques can then be applied to find explicit isomorphisms between realisations, and these give complementary upper bounds.

Speaker: Cristofero Fraser-Taliente

10 Fraser Taliente.pdf

41 FTheoryTools: A computational tool for analysis of singular elliptic fibrations

In this talk, I will discuss an upcoming computational tool for analysis of singular elliptic fibrations called FTheoryTools. This tool automates many of the difficult calculations involved in the analysis of F-theory models, and additionally hopes to catalogue and make available many of the constructions that appear throughout the F-theory literature so that anyone may easily do calculations with them. FTheoryTools is being written as a component of OSCAR, an open-source computer algebra system that is currently in development.

Speaker: Andrew Turner

11 Turner.pdf

42 Fano 3-Folds, Ypk Manifolds and Brane Brick Models

Speaker: Rak-Kyeong Seong

12 Seong.pdf

Parallel: Tue 2-B

Convener: Alexander Westphal

43 The cosmological constant is probably still zero

We consider a wide class of four-dimensional effective field theories in which gravity is coupled to multiple four-forms and their dual scalar fields, with membrane sources charged under the corresponding three-form potentials. Four-form flux, quantised in units of the membrane charges, generically generates a landscape of vacua with a range of values for the cosmological constant that is scanned through membrane nucleation. We list various ways in which the landscape can be made sufficiently dense to be compatible with observations of the current vacuum without running into the empty universe problem. Further, we establish the general criteria required to ensure the absolute stability of the Minkowski vacuum under membrane nucleation and the longevity of those vacua that are parametrically close by. This selects the current vacuum on probabilistic grounds and can even be applied in the classic model of Bousso and Polchinski, albeit with some mild violation of the membrane weak gravity conjecture. We note that there are other models where the membrane weak gravity conjecture is not violated but where the same probabilistic methods can be used to tackle the cosmological constant problem.

Speaker: Antonio Padilla

7 Padilla.pdf

44 Smearing and Unsmearing KKLT AdS Vacua

Gaugino condensation on D-branes wrapping internal cycles gives a mechanism
to stabilize the associated moduli. According to the effective field theory, this gives rise,
when combined with fluxes, to supersymmetric AdS4 solutions. We provide an approximate ten-dimensional description of these vacua. More precisely find the supersymmetry equations for type II AdS4 vacua with gaugino condensates on D-branes, in the framework of generalized complex geometry.

Speaker: Nicolas Kovensky

8 Kovensky.pdf

45 Smearing and Unsmearing KKLT AdS Vacua Part II

In the framework of generalized complex geometry, we solve the supersymmetry equations for type IIB AdS4 vacua with gaugino condensates on smeared D7-branes. We show that supersymmetry requires a (conformal) Calabi-Yau manifold and imaginary self-dual three-form fluxes with an additional (0,3) component. The latter is proportional to the cosmological constant, whose magnitude is determined by the expectation value of the gaugino condensate and the stabilized volume of the cycle wrapped by the branes. This confirms, qualitatively and quantitatively, the results obtained using effective field theory. As for the localized solution, it requires going beyond SU(3)-structure internal manifolds. Nevertheless, we show that the action can be evaluated on-shell without relying on the details of such complicated configuration. We find that no “perfect square” structure occurs, and the result is divergent. We compute the four-fermion contributions, including a counterterm, needed to cancel these divergences.

Speaker: Dimitrios Toulikas

9 Toulikas.pdf

46 Fayet-Iliopoulos D-Term in Non-Supersymmetric Heterotic String Orbifolds

The Fayet–Illiopoulos D–term is a common feature in N = 1 string vacua that contain an anomalous U(1) gauge symmetry, and arises from a one–loop diagram in string perturbation theory. The same diagram is generated in string vacua in which supersymmetry is broken directly at the string scale, either via spontaneous Scherk– Schwarz breaking, in which case the gravitino mass is determined by the radius of the circle used in the Scherk–Schwarz mechanism, or via explicit supersymmetry breaking by the GSO projections. We analyse the resulting would–be Fayet–Illiopoulos D–term in the non–supersymmetric string vacua and its contribution to the vacuum energy. A numerical estimate in an explicit tachyon–free string–derived model suggests that the would–be D–term contribution may uplift the vacuum energy to a positive value.

Speaker: Alonzo Rodrigo Diaz Avalos

10 Diaz_Avalos.pdf

47 Interpolation and cosmological constant in non-susy heterotic strings

We study d-dimensionally compactified non-susy heterotic string models, including interpolating models with the arbitrary number of freely acting Z_2 twisted directions. Taking the limits of the compactified radii to zero and infinity, we show some examples of the various interpolation patterns in the d=2 (8-dimensional) case. In the region where supersymmetry is asymptotically restored, we evaluate the (10-d)-dimensional one-loop cosmological constant. We find out the points in the moduli space where the cosmological constant is exponentially suppressed.

Speaker: Yuichi Koga

11 Koga.pdf

48 Life-time of Metastable Vacuum in String Theory and Trans-Planckian Censorship Conjecture

We investigate the catalytic effect on the decay of a metastable vacuum in type IIB string theory. The decay bubble forms a bound state with an impurity, acting as a catalyst due to the non-linear DBI action. The vacuum's lifetime is calculated beyond the WKB approximation, and it satisfies the Trans-Planckian Censorship Conjecture (TCC) if the string scale is sufficiently smaller than the Planck scale.

Speaker: Sohei Tsukahara

12 Tsukahara.pdf

Parallel: Tue 2-C

Convener: Luca Martucci

49 Entropy bounds and the (Species Scale) Distance Conjecture

In this talk we will present a bottom-up argument for the AdS Distance Conjecture and the Distance Conjecture based on the Covariant Entropy Bound as applied to the EFT. By applying it to universal running solutions inspired by Dynamical Cobordisms in theories with a moduli space, we are able to recover the key features of the Distance Conjecture, namely the exponential decay of the mass scale of the tower and the geodesic paths in moduli space, upon identifying the UV cut-off with the species scale. Moreover, this naturally provides universal lower and upper bounds on the asymptotic decay rate of the species scale, which we formulate as a convex-hull condition under the name of Species Scale Distance Conjecture (SSDC).

Speaker: Alvaro Herraez

7 Herraez.pdf

50 The Quantum Gravity cut-off in a 'Nutshell'

Recently, there has been a growing interest in the so-called Species Scale, which presumably provides an upper bound for the QG cut-off in our low energy EFTs weakly coupled to Einstein Gravity. In this talk, we will propose a lower bound for the (asymptotic) decay rate that the aforementioned scale should present in any theory consistent with QG in the UV, which should hold along any possible direction exploring infinite distance in moduli space. Such condition can be reformulated in terms of a "convex hull constraint", thus imposing non-trivial implications for our valid gravitational theories. We will also point out the relation between this species scale convex hull and the usual one constructed in terms the salar charge-to-mass vectors of the infinite towers of light states, highlighting the 'duality' between the two.

Speaker: Alberto Castellano

8 Castellano.pdf

51 On the origin of species thermodynamics

The species scale provides an upper bound on the ultraviolet cutoff of gravitational effective theories coupled to a number of light particle species. We derive a moduli-dependent expression of the species scale from the entropy of the smallest possible black hole in type II Calabi-Yau compactifications, matching with a recent proposal from the topological string. Then, we argue that the number of species has to be understood as an entropy, we propose a notion of energy and temperature of species and we discuss the laws of species thermodynamics. They have direct connection to established swampland conjectures and lead to a thermodynamic interpretation of them.

Speaker: Niccolo Cribiori

9 Cribiori.pdf

52 EFT strings and emergence

We revisit the Emergence Proposal in 4d N = 2 vector multiplet sectors that arise from type II string Calabi–Yau compactifications, with emphasis on the role of axionic fundamental strings, or EFT strings. We focus on large-volume type IIA compactifications, where EFT strings arise from NS5-branes wrapping internal four-cycles, and consider a set of infinite-distance moduli-space limits that can be classified in terms of a scaling weight w = 1, 2, 3. We extend some previous results and show how one-loop threshold effects of infinite towers of BPS particles generate the asymptotic behaviour of the gauge kinetic functions along these limits.

Speaker: Luca Melotti

10 Melotti.pdf

53 Dark Graviton Dark Matter

I will discuss a model of Dark Matter motivated by the (A)dS distance conjecture. In this model, Dark Matter is composed of a spin-2 Kaluza-Klein tower with spacing set by the observed cosmological constant. After a discussion of the model's theoretical features, I will present its phenomenology and observable signatures in cosmology.

Speaker: Georges Obied

11 Obied.pdf

54 Black hole extremality in nonlinear electrodynamics

We study black hole extremality in nonlinear electrodynamics motivated by the Weak Gravity Conjecture (WGC) and the Festina Lente (FL) bound. We consider the Euler-Heisenberg model and Dirac-Born-Infeld model in asymptotically flat scapetime, deSitter spacetime, and anti-de Sitter spacetime. We find that in all cases the extremal condition enjoys a certain monotonicity expected by the WGC. We also study the light charged particle contribution to modify the mass-charge relation of Nariai black hole and discuss possible implications for the FL bound. This talk is based on the collaborations with Wei-Ming Chen, Toshifumi Noumi, Hibiki Satake, and Kaho Yoshimura.

Speaker: Yoshihiko Abe

12 Abe.pdf

Wednesday, 5 July

Plenary: 7

Convener: Piljin Yi

55 Geometry of Higher Symmetries on (Non-) Compact F-/M-theory

By studying M-theory on singular non-compact special holonomy spaces X we demonstrate, via a process of cutting and gluing  of singularities that extend to the boundary of X, the appearance of 0-form, 1-form and 2-group symmetries in the resulting supersymmetric quantum field theory. By employing  gluing techniques we study the fate of these symmetries when these spaces become compact.  We highlight prototype examples of elliptically fibered non-compact Calabi-Yau manifolds,  dual to (non-) compact F-theory constructions, where we can compare these results with those encoded in the arithmetic structure of elliptic curves.

Speaker: Mirjam Cvetic

1 Cvetic.pdf

Recording

56 Fermionic higher-form symmetries

We present a new notion of generalized global symmetries, the fermionic higher-form symmetries. Examples of physical systems with such symmetries include free fermionic p-form gauge fields and the free limit of 6d (4,0) theory. We also discuss the gauging of fermionic higher-form symmetries, curved spacetime background and the swampland implications.

Speaker: Yi-Nan Wang

2 Wang.pdf

Recording

57 An introduction to symmetry theories

I will give a brief overview of what symmetry theories are,I will give a brief overview of what symmetry theories are, and how we can compute them in string theory constructions.

Speaker: Inaki Garcia-Etxebarria

3 Garcia-Etxebarria.pdf

Recording

10:30 Coffee break

Plenary: 8

Convener: Wolfgang Lerche

58 Infinite distance limits with defects

As part of a longer program aiming at deciphering the nature of the boundaries of moduli spaces in quantum gravity, we investigate certain infinite distance limits in the complex structure moduli space of F-theory compactified on Calabi-Yau threefolds. Our focus is on non-Kodaira degenerations of the elliptic fibration in codimension one. These describe infinite distance directions in open string moduli space and give rise to a rich variety of stable degenerations of the geometry. As one of the novelties compared to their counterparts on elliptic K3 surfaces, we interpret a class of such limits as dual decompactification limits with (non-perturbative) defects.

Speaker: Timo Weigand

4 Weigand.pdf

Recording

59 Taxonomy of Infinite Distance Limits

Speaker: Ben Heidenreich

5 Heidenreich.pdf

Recording

60 Tadpoles and gauge symmetries

Speaker: Severin Lust

6 S. Lust.pdf

Recording

12:30 Lunch

Plenary: 9

Convener: Fernando Quevedo

61 Carving out the open string effective field theory

Within perturbative string theory, the world sheet representation of the amplitude will exhibit non-trivial monodromy that is universal for the sector that contains the standard model amplitude.This universality can be incorporated into the S-matrix bootstrap to obtain bounds on the EFT. We will explore the resulting EFT space, and show that assuming maximal susy, one uniquely identifies Type-I string theory.

Speaker: Yu-tin Huang

7 Huang.pdf

Recording

62 Non-supersymmetric heterotic strings: gauge symmetry enhancement and one-loop cosmological constant in toroidal compactifications

In the absence of experimental evidence for supersymmetry, compactifications of the non-supersymmetric heterotic strings make their reappearance in the landscape of possibly phenomenologically-relevant backgrounds. In this talk we will analyse compactifications on string-size tori, focusing on the phenomenon of gauge symmetry enhancement at special points in moduli space. Concentrating on the circle, we find all the points that have non-Abelian gauge symmetries of maximal rank, and analyze their matter spectrum. We show that all gauge symmetry enhancements, and where they are realised in moduli space, can actually be obtained from an extended Dynkin diagram. Finally, we will present the computation of the cosmological constant at points of maximal enhancement and in their vicinity, as well as its Hessian, finding a surprising result.

Speaker: Mariana Grana

8 Grana.pdf

Recording

63 GenHET

Speaker: Mariana Grana

9 GenHET_Grana.pdf

Conference Photo

15:30 Coffee Break

18:30 Conference Dinner

Thursday, 6 July

Plenary: 10

Convener: Mirjam Cvetic

64 Species Entropy and Thermodynamics

The species scale provides a generic UV cut-off in quantum gravity. In this talk I discuss a thermodynamic interpretation of the species scale in terms of species entropy and species temperature. Species thermodynamics is closely related to recent swampland constraints.

Speaker: Dieter Lust

1 D. Luest.pdf

Recording

65 Bounds on Species Scale and the Distance Conjecture

For gravitational theories I will discuss the variation of the effective quantum gravity cutoff as a function of light scalar fields. From consistency of the EFT and black hole arguments I will derive a bound on the slope of the species scale valid at any point in the field space, including its interior, whereas in asymptotic region it implies that the mass of a tower of states cannot decrease faster than exponential.

Speaker: Max Wiesner

2 Wiesner.pdf

Recording

66 Sliding Towers, Dualities and the Species Scale

Speaker: Irene Valenzuela

3 Valenzuela.pdf

Recording

10:30 Coffee break

Plenary: 11

Convener: Antonio Padilla

67 Higher (s>2) spin field and parity measurement from galaxies

In this talk, I'll present the method of measuring higher (s>2) spin spectator field during inflation and parity violation from the four-point correlation function of galaxy clustering.

Speaker: Donghui Jeong

4 Jeong.pdf

Recording

68 De Sitter Dialectics

Speaker: Susha Parameswaran

5 Parameswaran.pdf

Recording

69 D-branes, Dark Energy and Pulsar Timing Arrays

In this talk I will discuss modifications of the post-inflationary evolution due to an epoch of DBI-kinetic domination, where longitudinal fluctuations of a D-brane (matter) couple disformaly to its transverse fluctuations. For suitable initial conditions, such epoch can rise the primordial gravitational wave spectrum at frequencies accessible to pulsar timing array (PTA) experiments, contributing to the recent observed signal. For a brane moving along a single angular direction, the scalar potential can trigger an early epoch of dark energy (EDE) around the recombination epoch, which may help relaxing the Hubble parameter H0-tension today. More speculative, if a subsequent potential contribution arises from non-perturbative effects, the same field can act as late time quintessence to explain today's acceleration.

Speaker: Ivonne Zavala

6 Zavala.pdf

Recording

12:30 Lunch

Parallel: Thu 1-A

Convener: Kang-Sin Choi

70 Full Landscape of Supersymmetric Pati-Salam Models from Intersection Brane Worlds

We construct a systematic method to complete the landscape of intersecting brane worlds with the example of supersymmetric Pati-Salam models. Moreover, we propose a concrete way to realize all the string-scale gauge coupling relations of generic intersecting brane models via introducing exotic particles.

Speaker: Rui Sun

1 Sun.pdf

71 Flavor, CP and Metaplectic Modular Symmetries in Type IIB Chiral Flux Vacua

We examine symmetries of chiral four-dimensional vacua of Type IIB flux compactifications with vanishing superpotential W=0. We find that the N=1 supersymmetric MSSM-like and Pati-Salam vacua possess enhanced discrete symmetries in the effective action below the mass scale of stabilized complex structure moduli and dilaton. Furthermore, a generation number of quarks/leptons is small on these vacua where the flavor, CP and metaplectic modular symmetries are described in the framework of eclectic flavor symmetry.
(Reference : 2305.19155 [hep-th])

Speaker: Takafumi Kai

2 Kai.pdf

72 Quark and lepton hierarchies from S4' modular flavor symmetry

We propose models in which the hierarchical structures of the masses and mixing in both quark and lepton sectors are explained by the S4' modular flavor symmetry near the fixed point Im \tau >> 1. The model provides the first explicit example which explains hierarchies of both quarks and leptons by a single modular flavor symmetry. The hierarchies are realized by powers of \epsilon := e^{2\pi i\tau/4} = O(0.01) and Im\tau ~ 5, where \tau being the modulus. The small parameter \epsilon plays a role of flavon in the Froggatt-Nielsen mechanism under the residual Z^T_4 symmetry, and powers of 2Im\tau in the Yukawa couplings are controlled by modular weights via the canonical normalization. The doublet quarks are identified to a S4^\prime triplet to explain the hierarchical structure of the quark mixing angles, while the doublet leptons are composed of three singlets for the large mixing angles in the lepton sector. We show that the S4' modular symmetry alone can explain the hierarchies in both quark and lepton sectors by O(1) coefficients. This work is based on arXiv:2301.07439 and 2302.11183 [hep-ph].

Speaker: Junichiro Kawamura

3 Kawamura.pdf

73 Root bundles: Applications to F-theory Standard model

Recently, root bundles entered the quest for F-theory standard model constructions without exotic vector-like pairs. I will provide an overview of these developments.

Speaker: Martin Bies

4 Bies.pdf

74 Towards natural and realistic E7 GUTs in F-theory

We consider phenomenological aspects of a natural class of Standard Model-like supersymmetric F-theory vacua realized through flux breaking of rigid E7 gauge factors. It was shown that three generations of Standard Model matter can arise quite easily in these models. We further find that many other Standard Model-like features can easily be compatible with these constructions. For example, dimension-4 and 5 terms associated with proton decay are naturally suppressed.

Speaker: Shing Yan Li

5 Li.pdf

75 Hairy Black Holes by Spontaneous Symmetry Breaking

We have studied hairy black hole solutions in Einstein(-Maxwell)-scalar-Gauss-Bonnet theory. The scalar field coupling function includes a mass and a quartic interaction term, and that the gravity action has U(1) symmetry. We assumed that the early stage of the formation of hairy black holes from the non-hairy ones, and so we considered the case when the scalar field is small near the black hole horizon. We argued that when the effective mass of the scalar field is negative, hairy black holes form in a symmetry-broken vacuum. This occurs near the horizon via spontaneous symmetry breaking, since the Gauss-Bonnet term is not effective at infinity. Our results show that these hairy black holes are stable under scalar field perturbations and the Goldstone bosons are trivial due to the regular boundary conditions. For the local U(1) symmetric case, we found that there are electrically charged hairy black holes with neutral scalar hairs, but no hairy black holes with electrically charged scalar hairs. This means that the spontaneous symmetry breaking associated with local U(1) cannot be realized in this theory.

Speaker: Miok Park

6 Park.pdf

Parallel: Thu 1-B

Convener: Jakob Moritz

76 No Asymptotic Acceleration without Higher-Dimensional de Sitter Vacua

There has recently been considerable interest in the question whether and under which conditions accelerated cosmological expansion can arise in the asymptotic regions of field space of a d-dimensional EFT. In this talk I will present a conjecture that such acceleration is impossible unless there exist metastable de Sitter vacua in more than d dimensions. That is, Asymptotic Acceleration Implies de Sitter' (AA⇒DS). Phrased negatively, the d-dimensionalNo Asymptotic Acceleration' conjecture (a.k.a. the `strong asymptotic dS conjecture') follows from the de Sitter conjecture in more than d dimensions. The key idea is that the relevant field-space asymptotics almost always correspond to decompactification and that the only positive energy contribution which decays sufficiently slowly in this regime is the vacuum energy of a higher-dimensional metastable vacuum. This result is in agreement with recent Swampland bounds on the potential in the asymptotics in field space from e.g. the species bound, but is significantly more constraining. As an intriguing observation, the asymptotic expansion that arises from compactifying a de Sitter vacuum always satisfies and can saturate the bound from the Trans-Planckian Censorship Conjecture.

Speaker: Gerben Venken

1 Venken.pdf

77 Number Theory and the Road to Heterotic Vacua

Heterotic toroidal orbifolds represent a powerful framework to inspect the landscape due to their modular properties. In this talk, I will extend the basic SL(2,Z)-symmetric setup to higher genera modular groups, and show how to construct the building blocks needed to compute the scalar potential and study brand new vacua.

Speaker: Nicole Righi

2 Righi.pdf

78 Challenges and new perspectives on dS vacua

In this talk I will discuss recently discovered challenges for dS vacua in the Large Volume Scenario and the anti-D3-brane uplift. In particular, I will discuss the effect of $\alpha'$ corrections on the metastability condition of the NS5-brane at the tip of a the Klebanov-Strassler throat which is crucial for the anti-D3-brane uplift. Thereby, we will discover how $\alpha'$ corrections to NS5-branes suggest a novel uplifting mechanism.

Speaker: Simon Schreyer

3 Schreyer.pdf

79 Characterizing negative scalar potentials: an Anti-Trans-Planckian Censorship Conjecture

While positive scalar potentials have been extensively studied in effective string theories, in this talk I will discuss properties of negative potentials. This is accomplished by an Anti-Trans-Planckian Censorship Conjecture (ATCC), inspired by a refinement of the TCC. The ATCC states that in a contracting universe, modes that become sub-Planckian in length violate the validity of the effective theory. I deduce a new asymptotic condition for the second derivative of the potential, implying a mass bound for scalar fields in anti-de Sitter solutions.

Speaker: Ludwig Horer

4 Horer.pdf

80 Perturbative de Sitter and Brane Inflation

RG-induced moduli stabilisation was recently proposed as a new mechanism that adapts to string theory a perturbative method for stabilising moduli without leaving the domain of perturbative control and without the inclusion of non-perturbative effects. In this talk, we briefly revise the necessary ingredients in the construction of this mechanism. In addition, we examine the cosmological implications of the corresponding scalar potential in the framework of brane-antibrane inflation and show that inflationary observables can be reproduced within the regime of parametric control of the four-dimensional effective field theory.

Speaker: Mario Ramos Hamud

5 Ramos-Hamud.pdf

81 Sharpening the boundaries between flux landscape and Swampland by tadpole charge

There is a candidate of string compactification background that has no Kähler moduli, which is the mirror of the rigid Calabi-Yau threefold. We studied Type IIB flux compactifications on the mirror space, corresponding to a T-dual of the DeWolfe-Giryavets-Kachru-Taylor model in Type IIA flux compactifications. The lack of Kähler deformations suggests it can be a suitable space for learning various Swampland conjectures by flux-based complex-structure moduli stabilizations. Indeed, we see that if we allow excessing D3 tadpole charge on the background, stable de Sitter vacua emerge. Although it is in the Swampland, we may clarify what control parameter characterizes the boundary between the landscape and the Swampland since there is almost no subtlety in the flux compactifications on the mirror of the rigid manifold. We may be able to examine further various Swampland conjectures by considering the background.

Speaker: Keiya Ishiguro

6 Ishiguro.pdf

Parallel: Thu 1-C

Convener: Niccolo Cribiori

82 The Asymptotic Weak Gravity Conjecture in M-theory

In this talk, I will focus on five-dimensional compactifications of M-theory on Calabi-Yau 3-folds. In particular, for gauge groups with a weak coupling limit, I will show that there exist many super-extremal states along every ray in the charge lattice, as predicted by the tower Weak Gravity Conjecture, for any consistent quantum gravity theory.
I will briefly characterize the possible weak coupling limits, building on an earlier classification of infinite distance limits in the Kähler moduli space of M-theory compactifications. The result is that weakly coupled gauge groups are associated to curves on the compactification space contained in generic fibers or in fibers degenerating at finite distance in their moduli space. These always admit an interpretation as a Kaluza-Klein or winding U(1) in a dual frame or as part of a dual perturbative heterotic gauge group, in agreement with the Emergent String Conjecture. Finally, the fact that every ray in the associated charge lattice either supports a tower of BPS or of non-BPS states, can be shown using the connection between Donaldson-Thomas invariants and Noether-Lefschetz theory, proving also that these states satisfy the super-extremality condition, at least in the weak coupling regime.

Speaker: Alessandro Mininno

1 Mininno.pdf

83 Towards AdS Distances in String Theory

The AdS Distance Conjecture proposes to assign a notion of distance between AdS vacua in quantum gravity. In my talk I will try to develop this idea. I will start proposing a sharp definition of a metric over the space of conformal variations of AdS through the action.. This metric turns out to be negative, making the distance ill-defined, a property relating to the famous conformal factor problem of quantum gravity. However, in string theory, variations of the AdS conformal factor are accompanied by variations of the internal dimensions and of the background flux. Interestingly, the inclusion of these variations can change the sign of the metric over the space of variations of AdS vacua. I will propose a consistent procedure to derive the distance between AdS vacua based on the new notion of action metric which accounts for all of these variations simultaneously. I will test this procedure focusing on AdS4 and AdS7 Freund-Rubin vacua in M-theory and I will show that it yields a well-defined and positive distance.

Speaker: Nicolo Petri

2 Petri.pdf

84 Conserved Currents at Infinite Distance in the Conformal Manifold

The first part of the CFT Distance Conjecture posits that all points in which there is a higher-spin symmetry enhancement are at infinite distance in the conformal manifold with respect to the Zadmolodchikov metric. Through the AdS/CFT correspondence, this proposal was initially motivated by the Swampland Distance Conjecture, one of the pillars of the Swampland Program. In this talk, I will discuss how to prove this statement using conformal perturbation theory and weakly-broken higher-spin symmetry. Only assumptions of the conjecture are used, namely having a CFT in more than two dimensions with a conformal manifold and the presence of a local stress-energy tensor. For instance, no supersymmetry is required.

Speaker: Jose Calderon Infante

3 Calderon-Infante.pdf

85 Running Decompactification, Sliding Towers and the Distance Conjecture

The Swampland Distance Conjecture (as well as its refinements) and the Emergent String Conjectures restrict the type of light towers that can appear as we move towards infinite distance limits in moduli space, as well as the exponential rate with which these new modes become light. We explore these conjectures in the moduli space of 9d N=1 supersymmetric theories, and for the first time, test them in the context of decompactification to running solutions, such as decompactification of Type I’ string theory in 9d with a nontrivial dilaton profile. As it turns out, while the exponential rate of the KK states (which are non-BPS and have a complicated moduli dependence for their masses) changes from the expected value, it does so in a way that still fulfills current bounds found in the literature. Finally, we comment on how the Scalar Weak Gravity Conjecture is met in a non-trivial way, with some of the towers generating the convex hull “sliding” as we move around moduli space.

Speaker: Ignacio Ruiz

4 Ruiz.pdf

86 Small Black Hole Explosions

4d small black holes are powerful tools to pursue dynamical explorations of infinite distances in moduli space. Upon $S^2$ compactification they exhibit the features of a Dynamical Cobordism, with a singular core, located at a finite distance in spacetime, at which some scalars run to infinity. In this talk, I will discuss such setups in the presence of an additional 4d scalar potential growing exponentially near the black hole core with a characteristic exponent δ. I will show that the small black hole behaviour is preserved for values of δ under a certain limit, while up to this bound the potential is too large, it obstructs the realisation of the Dynamical Cobordism, and the small black hole explodes. I will obtain such results in the 2d perspective, where the competition between the black hole and the scalar potentials is explicitly manifest. I will then show a realisation of these ideas in the context of 4d N = 2 gauged supergravities. Here the Freed-Witten conditions of the corresponding stringy background produce a new mechanism for explosions. Finally I will discuss the capability of small black holes to continue exploring infinite distance limits in moduli space, even in the presence of these additional 4d potentials.

Speaker: Roberta Angius

5 Angius.pdf

87 Emergent Ensemble Symmetries in Holography and Swampland

Dualities involving ensembles of theories represent a fascinating class of holographic correspondences. The inclusion of wormholes into a theory naturally motivates the study of ensembles, but doing so leads to many puzzles from the viewpoint of string theory. In this talk, I will discuss holographic dualities involving ensembles of 2D Narain conformal field theories. The bulk dual of a Narain ensemble is an Abelian Chern-Simons theory, but features a sum over 3D geometries. Generalizations of this correspondence lead to emergent ensemble symmetries – global symmetries that appear only after averaging over the ensemble and are the vestiges of T-duality in the CFT. These are intimately related to the anyons and 0-form symmetries of Chern-Simons theories. I will also discuss the relation of these emergent global symmetries with recent ideas in quantum gravity, and furthermore generally discuss the role of ensemble averaging in standard holography, the Landscape, and the Swampland.

Speaker: Jacob Leedom

6 Leedom.pdf

15:30 Coffee break

Parallel: Thu 2-A

Convener: Sungjay Lee

88 $(p-1)$-Bracket for D$p$-branes in Large R-R Field Background

The volume-preserving diffeomorphism is a key feature that characterizes the large constant R-R ($p-1$)-form field background in a D$p$-brane theory. It represents a symmetry of the theory that preserves the volume of space. To describe this symmetry, we introduce the concept of the ($p-1$)-bracket, which generates the volume-preserving diffeomorphism. The ($p-1$)-bracket is a mathematical operation that acts on ($p-1$)-forms and encodes the transformation of the background field under the symmetry. To generalize the ($p-1$)-bracket, we can apply it to the non-Abelian one-form gauge field, which is relevant in gauge theories with non-Abelian gauge groups. This allows us to extend the concept of volume-preserving diffeomorphism and its associated symmetry to non-Abelian gauge theories. When considering D-branes and T-duality, we introduce the transverse coordinates of the branes. T-duality is a symmetry transformation that relates String Theory compactified on different backgrounds. It exchanges the momentum and winding modes of strings and leads to an equivalence between theories with different numbers of dimensions. By incorporating T-duality and the generalized bracket, a general expression for the action in D$p$-branes can be derived when $p\le 6$. This result connects the existing construction of D$p$-branes with our generalized bracket, illustrating the relationship between the symmetry and its associated transformations and the dynamics of the branes. In addition, we can discuss the non-Abelianization of the ($p-2$)-form gauge potential. This process involves generalizing the concept of non-Abelian gauge fields to higher-form gauge potentials. By extending the Lagrangian description of a single D-brane to multiple D-branes, a similar Lagrangian description can be established for both cases, highlighting the common underlying structure and symmetry properties. Our developments demonstrate the interplay between symmetries, gauge fields, and D-brane dynamics, providing a deeper understanding of the underlying principles within D-branes.

Speaker: Chen-Te Ma

7 Ma.pdf

89 Generalised Bismut-Lichnerowicz formulae and quantum corrections in string theory

From a quantum gravity point of view, higher-derivative corrections serve as means of probing String Theory at a fundamental level. Even though the complete expansion involves all fields of the theory, most of the attention has been concentrated on the gravitational action. The gravitational part of the first higher derivative corrections to M-theory, which begins at eight derivatives, has been recently reinterpreted in the framework of generalised geometry based on an M-theoretic Lichnerowicz formula. It suggests to modify the supersymmetry transformations to incorporate the gravitational Chern-Simons term needed for the consistency of the theory. Recent progress in the classification of string backgrounds using Generalised Complex Geometry raises hopes that this formalism together with duality covariance, which provides rather powerful constraints on the structure of the quantum corrections in the effective actions, should allow to recover the higher-derivative corrections in their entirety. We derive (IIA/HET duality manifest) generalised Bismut-Lichnerowicz formulae that describes 6d N=(1,1) supergravities beyond two derivative-level.

Speaker: Yi Zhang

8 Zhang.pdf

90 Strings, D-branes, and supergravities from supermembranes with discrete spectra

M2-branes with fluxes correspond to sectors of M-theory on a torus with good quantum behavior, like the discreteness of the supersymmetric spectrum. Consequently, these particular M2-branes may describe microscopical degrees of freedom of, at least, a sector of M-theory. In this talk, we will identify non-perturbative objects of type II string theory that are directly related to M2-brane with fluxes. As standard bound states of SL(2,Z) (p,q)-strings with winding, we show that parabolic (p,q)-strings are also obtained from M2-branes with fluxes. The restriction on the symmetry group of the latter originates from the monodromy of the twisted torus bundles that globally describes the M2-branes with discrete spectra in 11D. Its low energy limit corresponds with type IIB parabolic gauge supergravity in 9D. Finally, we show that there are compact D-branes with worldvolume fluxes and nontrivial U(1) gauge symmetries, different from DBI, with a well-defined origin in these nontrivial sectors of M2-brane theory.

Speaker: Camilo las Heras

9 Las Heras.pdf

91 Free Fermionic Webs of Heterotic T-folds

Non-geometric string vacua are well know to play a key role in moduli stabilisation. In the context of heterotic orbifolds, models can be studied in terms of fermionic or bosonic formulations. At the heart of the connection between these two constructions is bosonisation that connects a single boson with 2 real fermions in the worldsheet CFT. The freedom to pair up fermions in a large number of different ways on one side of the heterotic string gives rise to many bosonic interpretations that would naively look distinct but are in fact identical at the self-dual/free fermionic point in the moduli space. We study such `free fermionic webs' of string models and show how the fermionisation transformations act on the bosonic orbifold input data. A striking implication of this analysis is how both symmetric and asymmetric bosonic orbifolds can be realised from the same free fermionic theory. We furthermore discuss moduli projection in this context and derive a condition on when a free fermionic model is intrinsically asymmetric, i.e. forbids a symmetric (geometric) interpretation.

Speaker: Benjamin Percival

10 Percival.pdf

92 Wilson loops, holomorphic anomaly equations and blowup equations

We investigate the topological string correspondence of the five-dimensional half-BPS Wilson loops on S1. First, we propose the refined holomorphic anomaly equations for the BPS sectors of the Wilson loop expectation values. We then solve these equations and obtain many non-trivial novel integral refined BPS invariants for rank-one models. By studying the Wilson loop expectation values around the conifold point, we obtain the quantum spectra of the quantum Hamiltonians of the associated integrable systems. Lastly, as an application, the study of this paper leads to a generalization of the blowup equations for arbitrary magnetic fluxes that satisfy the flux quantization condition.

Speaker: Xin Wang

11 Wang.pdf

93 Finiteness of flux vacua and the tadpole conjecture

Recently, the finiteness of self-dual flux vacua in F-theory has been established using the framework of tame geometry. In this talk, we present an alternative proof using the methods of asymptotic Hodge theory to provide a complementary and more hands-on perspective. This requires a detailed understanding of the nilpotent orbit expansion of the period map for an arbitrary number of complex structure moduli. We provide a concrete algorithm that allows one to compute such expansions in great generality based on the seminal work of Cattani, Kaplan and Schmid. These techniques may also give new insights into the tadpole conjecture.

Speaker: Jeroen Monnee

12 Monnee.pdf

94 Reducing differential systems for Feynman integrals and cosmological correlators

Many different integrals can be studied by considering them as solutions to differential equations. In this talk I will highlight a particular approach based on Gelfand-Kapranov-Zelevinsky (GKZ) systems, a class of integrals including Feynman integrals, period integrals, cosmological correlators and many more. In this setting it is quit simple to find solutions although these can be unwieldy to work with. Therefore I will also discuss how these systems can be reduced to simpler ones, which can then be solved explicitly and embedded in our original system.

Speaker: Arno Hoefnagels

13 Hoefnagels.pdf

Parallel: Thu 2-B

Convener: Jai-chan Hwang

95 Perturbations in O(D,D) string cosmology

Tensions in cosmology may be addressed by modifying our theory of gravity. String theory at low energies contains additional fields that are not present in general relativity but are naturally embedded in the O(D,D)-symmetric framework of double field theory (DFT). Moreover, the O(D,D) symmetry uniquely prescribes the interactions between the extended gravitational sector and other matter, leading to implications for string cosmology. After reviewing the basics of DFT, I will discuss some features of cosmological perturbations in this framework, including the evolution and mixing of fluctuations due to H-flux, conditions for conservation of curvature perturbations, as well as some implications for bouncing cosmologies.

Speaker: Stephen Angus

7 Angus.pdf

96 Progress in constructing KKLT de Sitter vacua

I present type IIB Calabi-Yau orientifold flux compactifications that contain all the necessary components of KKLT de Sitter vacua. Specifically, I exhibit 4-dimensional SUSY AdS vacua featuring conifold regions and small values of the superpotential, in which all moduli, including Kähler moduli, are stabilised in a controlled way. In these vacua the inclusion of a single anti-D3 brane makes the vacuum energy positive. We argue that in the absence of corrections to the Kachru-Pearson-Verlinde EFT, these configurations are de Sitter vacua, as suggested by KKLT. Detailed study of corrections to this EFT, and their effects on these vacua, is ongoing.

Speaker: Andreas Schachner

8 Schachner.pdf

97 Late-time accelerating cosmologies

I will characterize the late-time expansion rate of the universe in multi-scalar cosmologies with multi-exponential potentials, taking advantage of previously unobserved universal asymptotic features of the solutions to the cosmological equations. This provides a simple diagnostic of whether any given multi-exponential potential holds the necessary conditions for late-time cosmic acceleration. I will also discuss the conditions under which scaling solutions are inevitable late-time cosmological attractors for such theories. For scaling cosmologies, all field-space trajectories are known analytically, which allows one to characterize exactly any observable of interest. Multi-exponential potentials have been studied extensively as phenomenological models of quintessence and, moreover, they are ubiquitous in string-theoretic constructions. I will therefore sharpen several statements on the low-energy signatures of quantum gravity in this context.

Speaker: Flavio Tonioni

9 Tonioni.pdf

98 Cosmic Acceleration and Turns in the Swampland

We argue that field trajectories, which lead to cosmic acceleration and feature rapid turns near the boundary of the moduli space, are in the Swampland. We obtain this result by assuming the validity of the Swampland Distance Conjecture (SDC) in the presence of a positive (nearly-flat) scalar potential and by focusing on hyperbolic spaces, as prototype geometries of infinite distance limits of Calabi-Yau compactifications. We find that, in a quasi-de Sitter space with Hubble rate
H and acceleration parameter ε, the turning rate Ω is upper bounded such as Ω/H < O(√ε). Therefore, field trajectories consistent with the SDC can only have a negligible deviation from geodesics. This has direct implications for the realization and consistency of multifield scenarios in string theory. Moreover, it implies a tension between asymptotic accelerating expansion, consistent with observations, and the de Sitter conjecture.

Speaker: Guoen Nian

10 Nian.pdf

99 Implications of the gravitino mass/distance conjecture on inflation

The gravitino mass/distance conjecture states that an infinite tower of particles arises in the (large distance) limit of vanishing gravitino mass. An application of the conjecture to an inflationary spacetime gives us a lower bound on the gravitino mass in terms of the Hubble parameter whereas the requirement of positive inflationary energy and the structure of the supergravity potential give us an upper bound. We study the consequences of the bounds taking into account the time dependence of the gravitino mass and the Hubble parameter. We classify the landscape of the supergravity inflation models in terms of the supersymmetry breaking scale, the gravitino mass, and the $R$-symmetry, to obtain constraints on each class of inflation models.

Speaker: Takahiro Terada

11 Terada.pdf

100 Kination in String Theory

I will discuss some theoretical and phenomenological implications of a string theory-inspired, cosmological phase of kination, dominated by the kinetic energy of a rapidly rolling scalar. In the first part of the talk, I will describe how such a kination epoch can naturally arise in string compactifications after inflation, focusing on the case where it is driven by the volume modulus. I will also show how a phase of volume kination for approximately no-scale vacua (such as LVS) can be uplifted to a classical Kasner solution in 10d where the non-compact dimensions collapse towards a Big Crunch, in contrast with the standard picture of decompactification limits. In the second part of the talk, I will discuss possible solutions to the "overshoot problem", which takes place if the kinating scalar is able to overcome the barrier separating the vacuum from runaway directions. I will show how, assuming a sufficiently large hierarchy between the inflationary scale and the weak scale, initial seed radiation will be enough to locate the system to a tracker solution where the problem is avoided. This can be regarded as an anthropic argument for a large inflation/weak hierarchy.

Speaker: Filippo Revello

12 Revello.pdf

101 A Boltzmann equation approach to string thermodynamics

Using interaction rates computed to second order in string perturbation theory, we pose a system of Boltzmann equations describing an ensemble of long open and closed strings in different regimes (which include high and low density of D-branes), for an arbitrary number of "effectively non-compact" directions, along which strings cannot wind. We find equilibrium distributions for all these systems and study their behaviour under fluctuations, which we use to estimate thermalization rates. We comment on the relevance of this scenario in early Universe cosmology and, time permitting, potential GW signals.

Speaker: Gonzalo Villa

13 Villa.pdf

Parallel: Thu 2-C

Convener: Erik Plauschinn

102 Heterotic strings and holomorphic factorization

I will discuss the relationship between heterotic string compactifications with supersymmetry broken by the Scherk-Schwarz mechanism and chiral fermionic CFTs with central charge 24. I will argue that the classification of the latter uplifts to a classification of the former in six or more dimensions, and demonstrate it explicitly for four distinct compactifications of the aforementioned type with rank reduction by 8.

Speaker: Hector Parra De Freitas

7 Freitas.pdf

103 Affine algebras at infinite distance limits in the Heterotic string

In this talk, we will discuss the weakly coupled Heterotic string compactified on $T^d$ at the boundaries of the moduli space. Emphasising especially the case d=2 which is dual to F-theory on K3, we study the behaviour as one approaches these infinite distance limits from the worldsheet point of view, showing the relation with the complementary Kulikov model perspective. In particular, we analyze the link between the light KK modes associated to decompactification and affine algebras, which are related to the finite version appearing in the higher dimensional theory.

Speaker: Veronica Collazuol

8 Collazuol.pdf

104 Open-Moduli Infinite-Distance Limits in Six-Dimensional F-Theory

We analyze infinite-distance limits in the complex structure moduli space of six-dimensional F-theory, giving an algebro-geometric classification and a physical interpretation. From the point of view of the Swampland Program, the motivation is to understand the fate of open-moduli infinite-distance limits in relation with the Distance Conjecture. From an F-theory perspective, the infinite-distance limits correspond to suitable non-minimal singularities in codimension one and higher. While codimension-two finite-distance non-minimal singularities have been understood as SCFTs in a major classification effort, the goal of our analysis is to elucidate the meaning of the infinite-distance codimension-one and codimension-two non-minimal singularities. We argue why the limits over $\mathbb{P}^{1}$-fibered bases are a natural starting point for the detailed analysis, and comment on our results showing that they are either decompactification or emergent string limits in a dual sense.

Speaker: Rafael Alvarez-Garcia

9 Alvarez-Garcia.pdf

105 Cosmological Constant Extrema in the O(16)xO(16) Heterotic String on S^1

Circle compactifications of the O(16)xO(16) non-supersymmetric heterotic string give rise to a non-vanishing cosmological constant which is extremized in particular at points in the classical moduli space where the gauge symmetry is fully enhanced. By finding the fundamental region of this moduli space we are able to determine these points and study their spectrum at the massless and tachyonic level, finding that out of a total of 107 maximal enhancements, eight are tachyon-free, and furthermore have positive cosmological constant. We determine the profile of the cosmological constant near these points and find that four are saddle points and the other four live at the boundary of the tachyonic region in field space. In this way we show explicitly that every point of maximal symmetry enhancement is unstable with respect to this spacetime potential.

Speaker: Bernardo Fraiman

10 Fraiman.pdf

106 Non-geometric flux compactifications and the Swampland

Non-geometric flux compactifications of string theory constructed using Landau-Ginzburg techniques provide novel testing grounds for various swampland conjectures. In this talk, we discuss such constructions in the context of the tadpole conjecture.

Speaker: Muthusamy Rajaguru

11 Rajaguru.pdf

107 Global Anomaly Cancellation in Non-Supersymmetric Strings

We review the cancellation of local anomalies through Green-Schwarz mechanism in the three non-supersymmetric, tachyon-free string theories. We then discuss global anomalies and their relation to cobordism groups. We finally prove that global anomalies vanish in these three theories by showing that the relevant cobordism classes are trivial.

Speaker: Matilda Delgado

12 Delgado.pdf

108 Cobordism and Bubble of Nothing Decays in String Theory

The Cobordism conjecture states that the internal manifold of string compactifications needs to be cobordant to nothing. This is precisely the condition for bubbles of nothing to be topologically allowed. It is now a question of dynamics whether decays to nothing occur and if one can compute the decay rate. I will present an approximation of the decay rate to nothing for string theory Calabi-Yau compactifications.

Speaker: Bjoern Friedrich

13 Friedrich.pdf

Friday, 7 July

Plenary: 12

Convener: Timm Wrase

109 On Classical de Sitter Solutions and Quantum Transitions

Speaker: Fernando Quevedo

1 Quevedo.pdf

Recording

110 Axion-Photon couplings in type IIB string theory

In this talk I will consider the axiverse of RR four-form axions in type IIB Calabi-Yau orientifold compactifications, and focus on the computation of axion photon couplings and hierarchies that arise in the many axion limit — i.e. at large values of $h^{1,1}$. In particular, I will discuss two distinct phenomena that hierarchically suppress axion photon interactions when the QED divisor is small: the former is a suppression in ratios of mass scales that decouples all axions lighter than the QED axion. The latter is geometric in origin: at most a handful of mass eigenstates have internal wavefunctions that significantly overlap with QED. Equipped with these insights I will present preliminary data on cosmic birefringence, misalignment dark matter production, the ``irreducible axion background'' from freeze-in, and X-ray spectra from decaying axions.

Speaker: Jakob Moritz

2 Moritz.pdf

Recording

111 Torsion in cohomology and dimensional reduction

Speaker: Fernando Marchesano

3 Marchesano.pdf

Recording

10:30 Coffee break

Plenary: 13

Convener: Susha Parameswaran

112 Imprints of string theory in low energy observables

In this talk, I will discuss string theory may have characteristic predictions in certain low energy observables such as axion couplings and electric dipole moments (EDMs) of nucleons and atoms. It will be shown that axions identified as the zero modes of stringy n-form gauge fields are predicted to have their couplings to the SM fermions (e.g. electrons) comparable to the SM gauge fields (e.g. photons) in contrast to axions identified as the phases of complex scalar fields (as assumed in the KSVZ and DFSZ models). On the other hand, string theory predicts a nearly flat logarithmic distribution of the QCD axion vacuum expectation value over the landscape. Therefore it may give rise to EDMs of nucleons and atoms by a sizable QCD theta angle. I will show that such QCD theta-dominated CP violating scenario can be discriminated experimentally from other BSM scenarios by measurements of the EDMs of diamagnetic atoms.

Speaker: Sang Hui Im

4 Im.pdf

Recording

113 Ultralight axions in string cosmology

I will discuss the role that ultralight axions can play in string cosmology. These particles emerge very naturally in string compactifications where the effective field theory is under control and can behave as dark radiation, early dark energy, dark matter or quintessence-like dark energy. Moreover, they can produce detectable CMB birefringence signals. At the end of the talk I will also describe the activities of the newly born COST action COSMIC WISPers in the Dark Universe: Theory, astrophysics and experiments.

Speaker: Michele Cicoli

5 Cicoli.pdf

Recording

114 D-term Uplift, Moduli Fixing and SVD in Heterotic-String Vacua

Speaker: Alon Faraggi

6 Faraggi.pdf

Recording

12:30 Lunch

Plenary: 14

Convener: Dieter Lust

115 Heterotic/F theory dual SU(5) model

In this talk I present some results of a Heterotic/F theory dual global SU(5) model with Wilson line breaking of SU(5) down to the Standard Model gauge symmetry. The model contains 3 families of quarks and lepton doublets and one pair of Higgs doublets. We solve the problem of vector-like exotics which stymied the use of Wilson line breaking in the past. Our model has a complete twin sector and a Z_2 and Z_4^R symmetry which prevents dimension 4 and 5 baryon and lepton number violating operators.

Speaker: Stuart Raby

7 Raby.pdf

Recording

116 Emergence in Quantum Gravity and the Scales of Fundamental Physics

The ‘emergence ‘ conjecture in quantum Gravity proposses that all kinetic terms of light particles below the UV cut-off arise in the IR via loop corrections. We study implications of this Emergence Proposal for fundamental scales in the Standard Model. These appear due to the presence of towers of states giving rise to large wave function renormalisation. In this scheme the hierarchy of quark and lepton masses is a reflection of flavour towers just below the UV scale. The smallness of neutrino masses appear due to the existence of a tower of singlets with mass around 700 TeV. Using the AdS Swampland constraint forcing the lightest neutrino mass to be smaller than the c.c. scale, we then describe how all fundamental scales in physics may be written in terms of powers of the c.c.

Speaker: Luis Ibanez

8 Ibanez.pdf

Recording

117 QG bounds, Gauss-Bonnet & wormholes

Perturbative regimes of gravitational d=4 N=1 effective field theories are characterised by special fundamental axionic strings, the so-called EFT strings. Applying the completeness hypothesis to these strings and demanding their quantum consistency, one can derive bounds on the EFT, and in particular on the Gauss-Bonnet term. I will discuss some implications of these bounds on the non-perturbative effects generated by axionic wormholes.

Speaker: Luca Martucci

9 Martucci.pdf

Recording