Instituto de Física Teórica

GRASS Seminar: 'Axions, Three-Forms, and M-Theory'
2026-01-14 15:00 - 17:00 (Europe/Madrid) | IFT Seminar Room/Red Room, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Gravity, Supergravity and Superstrings (GRASS) Seminar
Speaker: Ziqi Yan (Niels Bohr Institute, Denmark)
Venue & Time: Red Room / 15:00
Abstract: Scalar fields with masses protected by global shift symmetries, commonly referred to as axions, are abundantly used in effective field theories in cosmology and particle physics. I will discuss a (4+1) dimensional braneworld construction for axion-like particles, where a 3-brane is coupled to a flux in the fifth dimension orthogonal to the brane, and its uplift to M-theory. From the (3+1)-dimensional perspective, this construction generates a mass for the axion and matches previously known proposals based on the coupling between the axion and a three-form gauge field.

SPS Journal Club: 'Exotic Branes and Symmetries of String Theory'
2026-01-15 12:00 - 13:00 | IFT Seminar Room/Red Room, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Speaker: Andriana Makridou (IFT)
Venue & Time: Red Room / 12:00
Abstract: Are duality transformations symmetries of string theory? For AdS space-time the answer is
no for generic asymptotic values of the moduli, since the duality symmetry is broken explicitly
in the dual conformal field theory. In contrast, in string theory in flat space-time, monodromy
around codimension two exotic branes show that duality transformations are spontaneously
broken discrete gauge symmetries with observable consequences, provided macroscopic loops
of these branes are not hidden behind an event horizon. We discuss how this can be achieved
and how the situation in flat space-time differs from that in AdS space-time. We also discuss
observability of codimension two non-BPS branes and codimension one BPS and non-BPS
branes. Based on [2512.19068].

Pheno Journal Club: 'Bubble velocities in local equilibrium from a pseudopotential'
2026-01-15 12:00 - 13:00 | Gray Room 3, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Speaker: Eric Madge, IFT
Venue&Time: 12:00 / Grey room 3
Abstract: We present a new method to estimate terminal bubble velocities during first-order phase transitions in a plasma in local equilibrium. The method relies on calculating the extrema of a modified potential function for the scalar field undergoing the transition. The shape of this function, which we refer to as the “pseudopotential”, changes with the wall velocity, and if the dependence of the fluid temperature on scalar gradients is weak—which is confirmed to hold with high accuracy in concrete examples—the difference in pseudopotential between two appropriate extrema gives the net outward pressure acting on the bubble wall. It then follows that the correct terminal bubble velocities are those that lead to degenerate minima in the pseudopotential. This allows to compute bubble velocities without having to solve the equation of motion of the scalar field, and in contrast to other methods this can be done without relying on simplified equations of state for the plasma or without choosing a specific ansatz for the scalar field profile. We illustrate the method in a singlet extension of the Standard Model, computing the net outward pressure as a function of the wall velocity. We confirm the dip in outward pressure found in the literature for hybrid bubbles, which implies that stationary deflagrations are stable, while their detonation counterparts are unstable

Seminar: 'Dark Sector Karaoke: A 3D EFT for a Pitch-Perfect Phase Transition'
2026-01-15 15:00 - 16:00 | IFT Seminar Room/Red Room, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Speaker: Cristina Puchades Ibáñez (University of Mainz)
Venue & Time: Red Room / 15:00
Abstract: We explore the dynamics of cosmological phase transitions in a dark sector model featuring a dark photon associated with a U(1)D gauge symmetry and radiative symmetry breaking. Our analysis focuses on different approaches to construct the effective potential: the high-temperature approximation, a full numerical evaluation of the thermal integrals, and a dimensionally reduced 3D effective theory built with DRalgo, at both leading and next-to-leading order. We as well explore the effect of including the running of the parameters in order to respect the hiercarchy scales. We investigate how these methods impact the characterization of the phase transition, particularly in the supercooled regime. Our results show the importance of method choice when predicting observable signatures, and establish a benchmark for future studies of first-order phase transitions in models with weakly coupled dark sectors.

Cosmology Journal Club
2026-01-20 14:00 - 15:00, 2026-02-10 14:00 - 15:00 | Discussion room 5th floor, C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, Madrid, 28049, Spain
Every Tuesday at 2:00 PM in the discussion room on the 5th floor.
Join the IFT cosmology/gravity journal club at benty-fields.com to vote for papers and volunteer to present them.

SPS Journal Club: 'K-Points and Type IIB/Heterotic Duality with NS5-Branes'
2026-01-22 12:00 - 13:00 | IFT Seminar Room/Red Room, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Speaker: Lorenzo Paoloni (IFT)
Venue & Time: Red Room / 12:00
Abstract: We revisit type II_0 limits in the vector multiplet moduli space of compactifications of Type IIB string theory on Calabi-Yau threefolds. These limits are special because they cannot be described using mirror symmetry. While we showed in previous work that the gravitational duality frame emerging in such limits corresponds to a weakly coupled heterotic string compactified on K3 times a string-sized torus, our focus here is on the additional field theory sectors that decouple from gravity in these asymptotic regimes. Concretely, we argue that, in the dual heterotic description, these field theory sectors correspond to spacetime-filling NS5-branes wrapping the heterotic torus. The existence of such non-perturbative field theory sectors manifests itself in an exponential dependence of the prepotential on the heterotic dilaton at leading order. Applied to K-point limits in one-parameter moduli spaces, our results imply that these limits are in perfect agreement with the Distance and Emergent String Conjectures. More precisely, the light tower of states predicted by the Distance Conjecture arises from excitations of a weakly coupled heterotic string compactified to four dimensions on a background containing spacetime-filling NS5-branes.

Pheno Journal Club
2026-01-22 12:00 - 13:00
Every Thursday at 12:00 in Grey Room 3.

Seminar: 'Reviving PBHs: primordial black holes from supercooled phase transitions revisited'
2026-01-22 15:00 - 16:00
Speaker: Piotr Toczek (Warsaw University)
Venue & Time: 15:00 / Red Room
Abstract: Primordial black holes, hypothetical objects that may have formed in the early Universe through the interplay between high-energy physics and gravity, are very appealing candidates for dark matter. In this seminar, I will discuss their formation as a result of the collapse of energy density fluctuations originating from supercooled first-order phase transitions. I will present the formalism that we use to track the evolution of such fluctuations in a fully covariant manner, explicitly incorporating the spacetime metric perturbations. I will show which aspects of the phase transition drive the growth of density fluctuations and their gravitational collapse, and identify the transitions for which the produced population of primordial black holes may constitute a significant fraction of the total dark matter abundance.

Old Journal Club: 'Particle Spectrum in Quantum Field Theory'
2026-01-22 17:00 - 18:00 | Blue Room, Instituto de Física Teórica (IFT) - C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Alejandro Puga (IFT) will present “Particle Spectrum in Quantum Field Theory” de Alexander M. Polyakov (JETP Lett. 20 (1974) 194-195)

Abstract: We investigate the nonperturbative structure of quantum field theories and its consequences for the physical spectrum of excitations. Emphasis is placed on the role of instantons—topologically nontrivial field configurations—which contribute essentially to tunneling processes and mass generation beyond perturbation theory. The analysis demonstrates how instanton effects modify correlation functions and lead to qualitatively new features in the particle spectrum, highlighting the deep connection between topology, symmetry, and dynamics in quantum field theory.

Venue & Time: Blue Room / 17:00

Cosmology Journal Club
2026-01-27 14:00 - 15:00, 2026-02-03 14:00 - 15:00

ML-AI-HPC Jounal Club: 'Probabilistic modeling and Bayesian inference for collider data'
2026-01-29 11:00 - 13:00 | Gray Room 1, Instituto de Física Teórica, C/ Nicolás Cabrera 13-15, Cantoblanco, Madrid, Madrid, 28049, Spain
Title: ‘Probabilistic modeling and Bayesian inference for collider data’
Speaker: Santiago Tanco (IFLP-CONICET/UNLP)
Venue&Time: Gray Room 1 / 11:00

Polygonal Gravity Seminars
2026-01-29 11:30 - 16:30 | IFT Seminar Room/Red Room, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Madrid’s Polygonal Gravity Seminar Series
Wednesday, January 29th. Blue Room (IFT)

11:30h First talk

Speaker: Robie Hennigar (U. Durham, UK)
Title: Building Regular Black Holes

Abstract: The study of regular (singularity-free) black holes has a long
history, but progress has been limited by the absence of a dynamical
framework in which they form and by conceptual issues at the kinematical
level. In this talk I will discuss recent work in which spherically
symmetric regular black holes emerge as unique solutions of gravity
theories with infinite towers of higher-curvature corrections, enabling
explicit analyses of their formation and dynamics. I will review the
construction, summarize key results, and highlight open problems.

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12:45-14:15 Lunch break

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14:30h Second talk

Speaker: Pablo Cano (U. Murcia)

Title: Amplification of new physics in the quasinormal mode spectrum of
highly-rotating black holes

Abstract: The computation of quasinormal modes of rotating black holes in
modified theories of gravity has been recently made possible thanks to the
development of new techniques, like a modified Teukolsky equation and
spectral methods. However, no method so far has been able to peek into the
highly rotating regime — close to extremality. In this talk, I will
consider a newly identified higher-curvature modification of GR that
preserves the isospectrality of quasinormal modes in the eikonal limit. In
this theory, eikonal perturbations can be described in terms of an
effective scalar equation, and solving it we will obtain the corrections
to the eikonal Kerr quasinormal modes for arbitrary rotation. For moderate
rotation, we check that the eikonal computation gives a good approximation
to the exact QNMs obtained from the modified Teukolsky equation, even for
low harmonics. For high rotation, we discover that the corrections to GR
become much larger and can lead to dramatic effects. Our results suggest
that the observation of the ringdown of a highly rotating black hole would
be a “golden event” to search for new physics.

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More information about these and following monthly seminars can be found at the webpage

SPS Journal Club: 'Mapping moduli across heterotic conifolds'
2026-01-29 12:00 - 13:00 | IFT Seminar Room/Red Room, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Strings, Pheno and the Swampland Journal Club

Title: ‘Mapping moduli across heterotic conifolds’

Speaker: Christian Aoufia (IFT)

Venue & Time: Red Room / 12:00

Abstract: In this work, we provide evidence for a duality between 4-dimensional Calabi-Yau compactifications of the heterotic string, in which the base manifolds are linked by a conifold transition. In recent work, a geometric proposal was put forward for how 5-branes and gauge bundles are carried across such transitions. It was observed that compactifications connected in this way lead to 4-dimensional effective theories with the same massless spectrum. Here we provide much stronger evidence that these heterotic conifold transitions do indeed lead to dual theories. We construct a duality map between the field spaces of the two compactifications and use it to demonstrate the agreement of large numbers of holomorphic functions appearing in the definition of the effective theories. In an example, we show that 147,440 independent superpotential Yukawa couplings agree across the duality as holomorphic functions of the moduli. In certain special cases, the putative duality studied here reduces to the target space duality of (0,2) gauged linear sigma models.

Pheno Journal Club: 'GeV-scale QCD Axion'
2026-01-29 12:00 - 13:00 | Gray Room 3, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Title: ‘GeV-scale QCD Axion’

Speaker: Thomas Steingasser (IFT)

Venue & Time: 12:00 / Gray Room 3

Abstract: In order to solve the strong CP problem, we study the possibility that the Peccei–Quinn symmetry is broken below the QCD scale. We find that a QCD axion can be above GeV, and may be among the observed η resonances. It is immune to quantum gravity corrections. The only fermion that has a U (1) Peccei–Quinn charge is the right-handed up quark. Flavor-changing neutral currents are surprisingly small, except for a possible but not necessary contribution to D0–D0 mixing. All accelerator and astrophysical limits can be evaded. The most significant constraint is the mass splitting between π± and π0. In a UV completed model, LHC can look for a dijet resonance in u ̄u,u ̄d, d ̄u channels.

Seminar by Ennio Salvioni (IFAE): 'Probing the Dark Sector with Large Scale Structure'
2026-01-29 15:00 - 16:00 | IFT Seminar Room/Red Room, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Title: ‘Probing the Dark Sector with Large Scale Structure’
Speaker: Ennio Salvioni (IFAE)
Venue&Time: Red Room / 15:00
Abstract: Precision cosmology offers opportunities to test the nature of dark matter independently of any interactions with the visible sector. I will discuss how data from galaxy surveys, including the ongoing DESI and Euclid projects, can be leveraged to probe new dynamics in the dark sector. For this purpose, I will show how to extend the Effective Field Theory of Large Scale Structure to include physics beyond the Standard Model, enabling perturbative computations of the power spectrum of galaxies. The scenarios I will discuss include long-range dark matter self-interactions, and sub-components of dark matter exhibiting suppressed growth of structure, such as ultra-light axions or light thermal relics.

Old Journal Club: 'Topological Quantization and Cohomology'
2026-01-29 17:00 - 18:00 | Blue Room, Instituto de Física Teórica (IFT) - C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Gonzalo F. Casas (IFT) will present ‘Topological Quantization and Cohomology‘ by Orlando Álvarez Commun.Math.Phys. 100 (1985) 279
Abstract:
The relationships between topological charge quantization,Lagrangians and various cohomology theories are studied. A very general criterion for charge quantization is developed andapplied to various physical models. The relationship betweencohomology and homotopy is discussed.
More info: https://inspirehep.net/literature/206164

Seminar: 'F(ℓ)avoured searches: new physics in the 3rd generation'
2026-02-02 15:00 - 16:00 | IFT Seminar Room/Red Room, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Title: ‘F(ℓ)avoured searches: new physics in the 3rd generation’
Speaker: Tamara Vázquez Schröder (IFAE)
Venue & Time: Red Room / 15:00

Abstract: The primary goal of the Large Hadron Collider (LHC) has been to discover the mechanism of electroweak symmetry breaking (EWSB). The discovery of the Standard Model (SM)-like Higgs boson in 2012 was the first step to achieve this. However, the underlying nature of EWSB remains unknown. Additionally, the SM cannot explain the origin of neutrino masses, the asymmetry between matter and antimatter in our universe, or the nature of dark matter and dark energy. It also cannot address important conceptual questions, such as why is the Higgs boson so light compared to the Planck scale, or what are the underlying dynamics through which the Higgs field provides masses to the fundamental particles. Even though the LHC has not discovered any Beyond the Standard Model physics, there are multiple hints in various areas of particle physics which could revolutionise our understanding of the elementary particles and the forces between them, leading to the start of a new Higgs and Flavour Era. In this talk I will dive into promising new physics models coupled preferentially to 3rd generation quarks or leptons that could address some of the shortcomings of the SM and could potentially explain some of the observed tensions in the particle physics landscape. Being potentially at the reach of the LHC collision energy, the search for these new physics signals in the multilepton final state could be the key to access a new era in particle physics exploration.

Quantum Information Journal Club: Continuous and field tensor network states
2026-02-04 11:30 - 12:30
Speaker: Albert Gasull, Leiden University

Venue & Time: Grey Room 3 / 11:30

Title: ‘Continuous and field tensor network states’
Abstract: Tensor network methods have provided us with a powerful set of tools with which to study strongly interacting many-body systems on the lattice. Understanding the limitations of this ansatz is paramount for the success of both numerical algorithms and exact analytical representations of the many-body wavefunction. In recent years, several generalizations making use of different notions of the continuum have appeared in the literature to tackle such different limitations. Firstly, continuous tensor network states (cTNS) is an ansatz that allows us to work directly in the continuum to answer questions related to quantum field theories, removing the need for sending the lattice spacing to zero in standard tensor network approaches. Secondly, field tensor network states (fTNS) aim to provide an exact tensor network approach to the analytical description of chiral gapped topological states in two spatial dimensions, such as the Laughlin wavefunction. While these states had been previously considered to be out of reach for the most prominent two dimensional tensor network, projected entangled pair states, by upgrading the virtual space of the network to an infinite dimensional one, we circumvent the previous no-go theorems to provide the first exact representations. In this talk, I will present an overview of both cTNS and fTNS. I will present the main ideas behind both generalizations and relation to quantum field theories. I will also showcase some of the applications that we are currently working on, as well as some of the problems that one encounters along the way. This talk is based on both published and ongoing work with Arkadiusz Bochniak, Germán Sierra and Ignacio Cirac.

Seminar: 'Co-Scaling and Alignment of Electric and Magnetic States'
2026-02-04 11:30 - 17:00 | IFT Seminar Room/Red Room, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Speaker: Tom Rudelius (Durham U., Dept. of Math.)

Title: Co-Scaling and Alignment of Electric and Magnetic States

Venue & Time: Red Room / 11:30

Abstract: Towers of electrically and magnetically charged states in quantum gravity often exhibit two important properties. First, the ratio of the mass (or tension) of electrically charged states to magnetically charged states is of order g^2, which we refer to as “co-scaling.” Second, in theories of multiple gauge fields, the towers of states that exhibit co-scaling have charges that point in approximately the same direction in charge space as measured by the gauge kinetic matrix, which we refer to as “alignment.” In this talk, I present heuristic arguments for and examples of co-scaling and alignment in the string landscape, and I discuss applications to phenomenology and cosmology.

Pheno Journal Club
2026-02-05 12:00 - 13:00 | Gray Room 3, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain

Strings, Pheno and the Swampland (SPS) Journal Club
2026-02-05 12:15 - 13:15 | IFT Seminar Room/Red Room, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Every Thursday at 12:00 in the Red Room.

Seminar by Yushi Mura (KEK)
2026-02-05 15:00 - 16:00 | IFT Seminar Room/Red Room, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Title: ‘UV completion of extended Higgs models via the confinement of SU(2) gauge’
Speaker: Yushi Mura (KEK)
Venue & Time: Red Room / 15:00
Abstract: The extended Higgs sectors are often introduced to explain phenomena beyond the standard model. On the other hand, the existence of multiple scalar fields may cause the Landau pole below the Planck scale. Therefore, those models should be replaced by more fundamental theory at high energies. In this talk, we consider an asymptotic-free SU(2) gauge theory as a UV-completion of the extended Higgs models and assume they are the consequence of confinement of the gauge theory. We find that particle contents of various extended Higgs sectors previously proposed are deduced by each charge assignment of flavor symmetry of the fundamental fermions of the SU(2) gauge symmetry.

Old Journal Club: 'Threshold production of heavy top quarks: QCD and the Higgs boson'
2026-02-05 17:00 - 18:00 | Blue Room, Instituto de Física Teórica (IFT) - C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Sergio Rodríguez (IFT) will present “Threshold production of heavy top quarks: QCD and the Higgs boson” by Matthew J. Strassler and Michael E. Peskin.
Abstract:
We calculate the threshold cross section for 𝑒+𝑒−→tt¯ to leading-logarithmic order in QCD, using a nonrelativistic approximation suggested by Fadin and Khoze. We study the mass range 100≤𝑚𝑡≤250 GeV, and show that the cross section is an excellent measure of α𝑠 for the lower portion of the mass range, while for a heavier top quark it is sensitive to the mass and couplings of the Higgs boson. We argue that a precise determination of 𝑚𝑡 and a measurement of Γ𝑡 are possible. We also show that nonperturbative effects are small, confirming that the tt¯ threshold is a detailed perturbative test of the standard model.
More info: https://journals.aps.org/prd/pdf/10.1103/PhysRevD.43.1500

Seminar: 'The Muon Magnetic Moment Mystery: a 20-year puzzle in high-energy physics'
2026-02-09 15:00 - 16:00 | IFT Seminar Room/Red Room, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Speaker: Zoltan Fodor (Penn State U.)
Venue & Time: Red Room / 15:00

Title: The Muon Magnetic Moment Mystery: a 20-year puzzle in high-energy physics
Abstract:
In the last two decades or so there have been stronger and stronger disagreements between direct measurements of the anomalous magnetic moment of the muon and the standard-model prediction. Such a large discrepancy would be a signal for an interaction or particle not present in the standard model. However, already in 2020 a lattice QCD calculation suggested a “no-tension” scenario. I report on our new lattice QCD calculation, which reduced the uncertainty of our 2020 result by about 40%. The agreement between the measured value of the anomalous magnetic moment of the muon and its theoretical predictions is an extremely impressive prove of the validity of quantum field theory –with three very different calculational frameworks for QED, EW and QCD– up to 11 digits.

Holo Club: 'Holographic fluids with higher-form symmetries'
2026-02-10 11:30 - 13:00 | Gray Room 3, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Title: Holographic fluids with higher-form symmetries

Speaker: André Oliveira (Heriot-Watt University)

Venue & Time: Grey Room 3 / 11:30

Abstract: Higher-form symmetries are ubiquitous in physics. In this talk, I focus on the case where they are continuous and encode the conservation of extended objects. Applications include elasticity, superfluidity and phases of electromagnetism. Using holography, we explore effective descriptions of systems with the simplest case of a single higher-form symmetry. For energies well below temperature, these descriptions admit a (potentially extended) hydrodynamic regime. We verify this explicitly by studying AlAdS black branes charged under higher-form potentials. In particular, we compute quasinormal modes, starting with the low-density limit. Then, we focus on the bulk dual of a viscoelastic system and analyse instabilities for different equilibrium states corresponding to isotropic crystalline phases.

2nd EDI Training: 'Beyond law: Invisible Barriers to Women’s Access to Public Life'
2026-02-11 16:00 - 17:00 | Blue Room, Instituto de Física Teórica (IFT) - C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Speaker: Soledad Escobar Villegas
PhD in Political Science and García Pelayo Research Fellow at the Centre for Political and Constitutional Studies, Ministry of the Presidency (Spain).
Abstract: Over the last decades, Western societies has introduced significant legislative changes aimed at promoting gender equality and increasing the representation of women in decision-making positions. However, legal progress does not always translate into equal participation in practice.
This seminar will examine the gender representation gap in politics and society by distinguishing between formal legislative advances and the structural constraints and internal dynamics within political and social environments that continue to limit women’s access to the public sphere. The session will analyze patterns of underrepresentation and explore factors such as unequal career progression, workplace cultures, and informal power structures. It adopts an intersectional approach, considering not only gender but also women’s ethnic and cultural backgrounds. The aim is to encourage students to critically assess how social and institutional systems shape women’s representation.
This seminar aligns with the objectives of the scientific outreach and culture component outlined in the Severo Ochoa project (CEX2020-001007-S, funded by MCIN/AEI/10.13039/501100011033). In addition to scientific excellence, this project highlights the center’s commitment to a strong program of training and outreach activities with high social impact. In this context, organizing training activities on equality, diversity, and inclusion helps to reinforce the role of the IFT as an institution committed to social responsibility and the continuous improvement of the scientific environment. This seminar provides tools to analyze the structural barriers present in the scientific field, particularly in STEM disciplines such as theoretical physics, aligning with the objectives of attracting and retaining diverse talent that foster an inclusive scientific environment.

Pheno Journal Club: 'The Cosmic Neutrino Background is within Reach of Future Neutrino Telescopes'
2026-02-12 12:00 - 13:00 | Gray Room 3, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Yuber Perez-Gonzalez (IFT) will present:

‘The Cosmic Neutrino Background is within Reach of Future Neutrino Telescopes’

Venue & Time: Gray Room 3 / 12:00

Abstract: The cosmic neutrino background (CνB) can be boosted to high energies due to scatterings with energetic cosmic rays (CRs) across cosmological scales. Previous calculations focused on neutral current incoherent and coherent elastic scatterings of cosmic-ray protons off relic neutrinos. However, charged current interactions and deep inelastic scatterings are also expected to occur, which enhances the boosted relic neutrino fluxes on Earth. Here, we compute the textit{total} diffuse boosted cosmic neutrinobackground (DBCνB) arising from CRs at all redshifts in the Universe, accounting for neutral current and charged current elastic and deep inelastic scatterings. We find that IceCube already places an upper limit on the cosmic neutrino background overdensity in cosmological scales of ~O(100−1000) at Eν=10^10 GeV, for a lightest neutrino mass of mν≳0.1 eV. We further show that IceCube-Gen2 could test O(1−10) CνB overdensities, and the combination of 10 future neutrino telescopes with similar sensitivity would allow us to test the ΛCDM expected CνB density for a lightest neutrino mass compatible with the KATRIN bound.

Based on 2601.09790.

SPS Journal Club: 'Hilltop quintessence, the LARGE Volume Scenario and varying-tension cosmic strings'
2026-02-12 12:00 - 13:00 | IFT Seminar Room/Red Room, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Léo Veissière (IFT) will present:

‘Hilltop quintessence, the LARGE Volume Scenario and varying-tension cosmic strings’

Venue & Time: Red Room / 12:00

Recent observational data suggests that the dark energy equation of state parameter wDE is evolving with time, in apparent tension with the ΛCDM standard model of cosmology. Here we review these observational results, with particular emphasis on the evidence for phantom-like behaviour, for which wDE < −1. In an attempt to reproduce the data, we study a quintessence model of a single scalar field rolling down a hilltop potential, both from a UV-agnostic perspective and from a string theory point-of-view. For the latter we focus on a scalar potential derived from type IIB supergravity in the context of the LARGE Volume Scenario (LVS), and investigate the cosmological dynamics of the scalar near its maximum. Finally, we discuss whether an effective phantom behaviour can be reproduced by considering the interaction between the scalar field and cosmic strings with a time-dependent tension, while keeping the LVS scalar potential unchanged.
