Instituto de Física Teórica

World Day for Cultural Diversity Celebration
2026-05-22 11:00 - 12:00 (Europe/Madrid) | Cafeteria (ground floor)
Thursday May21st and Friday May 22nd (during the usual coffee time). Both in the cafeteria

The EDI committee is hosting a small event this coming week to celebrate May 21st as the World Day for Cultural Diversity for Dialogue and Development, recognized by the UN and UNESCO.

Thursday:
World map set up with pins and flags to mark our coubtries of origin

Friday
International potluck during Friday coffee.

Whoever feels inspired can bring a small dish, snack, appetizer, or dessert to share – ideally something representative of their own culture or country—so we can all enjoy and discover flavors from around the world together.

Seminar: 'Weak Particles with a strong impact'
2026-05-25 15:00 - 16:00
Title: ‘Weak Particles with a strong impact’
Speaker: Aritra Gupta (Krea University, India)
Venue&Time: Red Room / 15:00
Abstract: Dark matter and neutrinos are among the most elusive particles in nature, yet they play a central role in the evolution of the Universe. Their extremely weak interactions make them difficult to detect, but also allow them to probe environments inaccessible to ordinary matter.
In this colloquium, I will discuss how astrophysical systems and neutrino observatories can be used to explore the physics of dark matter and neutrinos beyond the Standard Model. I will present scenarios where dark matter and neutrino physics are intimately connected, leading to observable consequences in cosmology and astroparticle experiments. I will also discuss how dark matter accumulated inside compact stellar environments can significantly modify supernova cooling along with other detectable indirect signatures. Throughout the talk, I will highlight how compact stars, neutrino detectors, and astrophysical observations together provide new windows into the dark sector.

Cosmology Journal Club
2026-05-26 14:00 - 15:00, 2026-06-02 14:00 - 15:00, 2026-06-09 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: Heterotic Ouroboros
2026-05-28 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 (SPS) Journal Club

Title: Heterotic Ouroboros

Speaker: Chiara Altavista (IFT)

Venue&Time: Red Room / 12:00

Abstract: M-theory on {mathbf{S}}^1vee{mathbf{S}}^1 has recently been proposed to yield, via quotients, ten-dimensional non-supersymmetric string theories. We revisit the construction that leads to the heterotic theories, finding a consistent set of rules that reproduces the light spectra and gauge groups, including indications of their global structure. Our approach uses the gauge enhancement mechanism of type I’ string theory, applied to a setting in which the type I’ interval is curled onto itself, with its two boundaries separated by a branch cut. Using these tools, we reproduce the ten-dimensional heterotic theories and provide some evidence for junctions among them.

Pheno Journal Club
2026-05-28 12:00 - 13:00, 2026-06-04 12:00 - 13:00 | Grey Room 2, Instituto de Física Teórica, Madrid, Madrid, 28037, Spain
Every Thursday at 12:00 in Grey Room 2.

Seminar by Marco Finetti (U. Aveiro)
2026-05-28 15:00 - 16:00
Title: ‘First Order Phase Transitions and Gravitational Waves’
Venue&Time: Red Room / 15:00
Speaker: Marco Finetti (U. Aveiro)
Abstract: The Laser Interferometer Space Antenna (LISA) will be the first space-based gravitational wave (GW) detector, opening a new observational window for both astrophysics and early-Universe cosmology. Operating in the millihertz band, it will probe a rich superposition of GW signals. Astrophysical population models predict a sufficient number of signals in the LISA band to blend together and form an irresolvable Galactic foreground noise. In addition, a stochastic gravitational wave background (SGWB) of cosmological origin could add an unknown component to the measured noise. In this talk, I will assess the bias induced on the parameter estimation of stochastic signals, arising from the unresolved binaries buried within the cosmological signal. Using a representative SGWB model, I will quantify the impact of this effect on the reconstruction of the foreground template parameters and, most importantly, on those of the SGWB model itself. Neglecting inter-template correlations can lead to significan biases, and, for several benchmark cases, those biases exceed the statistical reconstruction uncertainties. These findings expose a key limitation of existing template-based strategies and indicate that unbiased component separation will likely require additional information, such as constraints from resolved sources obtained through global-fit analyses.

Seminar: 'Classical Krylov probes and chaotic semiclassical strings'
2026-06-01 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: ‘Classical Krylov probes and chaotic semiclassical strings’
Speaker: Saskia Demulder (CUNEF)
Venue&Time: Red Room / 15:00
Abstract: Quantum chaos is a central theme in string theory, but classical chaos is also a generic feature of semiclassical string dynamics. Motivated by the need to explore the broad landscape of non-integrable string dynamics, I will introduce a classical version of Krylov complexity and related diagnostics using the Koopman-von Neumann formulation of classical mechanics. I will then explain how this framework can be applied to integrability-breaking deformations of otherwise integrable semiclassical string solutions. In particular, I will show how such deformations induce characteristic redistributions of spectral weight, leading to observable-dependent delocalisation and spreading in Koopman-Krylov space. This talk is based on [2602.23421] and ongoing work, both in collaboration with Rathindra N. Das.

Holo-Club: From Volume as a Clock to Boundary Dynamics in JT Gravity
2026-06-02 11:30 - 13:00 | Blue Room, Instituto de Física Teórica (IFT) - C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Title: From Volume as a Clock to Boundary Dynamics in JT Gravity
Speaker: Farbod-Sayyed Rassouli (University of Nottingham)
Venue&Time: 11:30 / Blue Room
Abstract:
Different notions of time arise from different choices of observer. In cosmological settings, a particularly natural choice is the spacetime volume, which is conjugate to the cosmological constant. This leads to a notion of unimodular time that deparametrizes the Wheeler–DeWitt equation into a Schrödinger-like evolution equation, while also inducing a natural time variable at the boundary. In this talk, I will first explain how this construction arises in arbitrary dimension, with particular emphasis on the 4D case. I will then turn to Jackiw–Teitelboim gravity, where promoting the vacuum cosmological constant to a dynamical top-form degree of freedom provides a bulk clock in the Henneaux–Teitelboim sense. On the boundary, this modifies the usual Schwarzian dynamics by coupling it to an additional U(1) phase mode, reproducing the universal low-energy structure familiar from complex SYK. I will show how the corresponding boundary theory can itself be rewritten as a (0+1)-dimensional observer action, making explicit the relation between the bulk volume clock and its holographic boundary counterpart.
arXiv:2601.07911

A diffuse flux of MeV ALPs
2026-06-02 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: ‘A diffuse flux of MeV ALPs’
Speaker: Marina Cermeño
Venue&Time: Red Room / 15:00
Abstract: MeV scale axion-like particles can be produced with semi-relativistic velocities in Galactic supernovae, leading to a diffuse flux that can be detectable in neutrino water-Cherenkov detectors (Super + HyperK). In this talk, I will explain the details of the calculation that we recently did in 2602.17597 also with some content from our previous works 2412.09595 , 2412.19890)

Quantum Information Journal Club: 'Polynomial-time thermalization and Gibbs sampling from system-bath couplings'
2026-06-03 11:30 - 12:30
Title: ‘Polynomial-time thermalization and Gibbs sampling from system-bath couplings’

Speaker: Sam Slezak (ENS Lyon)

Venue&Time: Gray Room 3 / 11:30

Abstract: Many physical phenomena, including thermalization in open quantum systems and quantum Gibbs sampling, are modeled by Lindbladians approximating a system weakly coupled to a bath. Understanding the convergence speed of these Lindbladians to their steady states is crucial for bounding algorithmic runtimes and thermalization timescales. We study two such families of processes: one characterizing a repeated-interaction Gibbs sampling algorithm, and another modeling open many-body quantum thermalization. We prove that both converge in polynomial time for several non-commuting systems, including high-temperature local lattices, weakly interacting fermions, and 1D spin chains. These results demonstrate that simple dissipative quantum algorithms can prepare complex Gibbs states and that Lindblad dynamics accurately capture thermal relaxation. Our proofs rely on a novel technical result that extrapolates spectral gap lower bounds from quasi-local Lindbladians to the non-local generators governing these dynamics.

IFT Colloquium: Matthew Headrick (Brandeis & IHES)
2026-06-03 15:00 - 16:30 | Blue Room, Instituto de Física Teórica (IFT) - C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Venue&Time: Blue Room / 15:00
Coffee will be served in the cafeteria at 16:15h
Title: ‘Black holes, quantum entanglement, and the geometry of spacetime’
Speaker: Matthew Headrick (Brandeis & IHES)
Abstract: Black holes are by far the most entropic objects in the universe, and their enormous entropy directly connects the macroscopic world governed by general relativity to the Planck scale governed by quantum gravity. It turns out that they are just a piece of a much larger and richer story, hinting that, despite the notorious difficulty of quantizing gravity, quantum mechanics and general relativity are actually two sides of the same coin. I’ll explain these connections, and along the way try to answer the question: Is Newton’s constant really equal to 1?

SPS Journal Club: 'Sharpened Dynamical Cobordism'
2026-06-04 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 (SPS) Journal Club

Title: Sharpened Dynamical Cobordism

Speaker: Alejandro Javier Puga Gómez (IFT)

Venue&Time: Red Room / 12:00

Abstract: We propose a sharpened version of Dynamical Cobordism, where the physical structure ξ of the theory in question determines an allowed range Rξ for the critical exponent δ. We interpret a singularity with δ∈Rξ as a true transition-to-nothing, i.e., a configuration ending spacetime, while a singularity with δ∉Rξ indicates some obstruction to such a transition, i.e., the presence of a non-trivial cobordism global charge, which is incompatible with a theory of quantum gravity. In the spirit of the original Cobordism Conjecture, this apparent inconsistency of the theory can be alleviated via the modification of the structure, for instance by introducing new degrees of freedom and associated defects. Inspired by the Gubser criterion for good singularities, we propose a way to determine Rξ. As a proof-of-concept we show explicitly how the introduction of a higher-form gauge field changes the allowed range of δ compared to an EFT with only scalars. We test this sharpened version of Dynamical Cobordism against several examples, such as massive IIA string theory, where it is notably compatible with the presence of O8-planes; the Janis-Newman-Winicour and Garfinkle-Horowitz-Strominger black hole solutions; and certain singular distributions of D-branes. In all these cases, the Sharpened Dynamical Cobordism Conjecture leads to results consistent with our expectations.

Old Journal Club: 'Cosmological Lower Bound on Heavy-Neutrino Masses'
2026-06-04 17:00 - 18:00 | Blue Room, Instituto de Física Teórica (IFT) - C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Valeria Costa (IFT) will present: Cosmological Lower Bound on Heavy-Neutrino Masses, de B. W. Lee y S. Weinberg.
Venue&Time: Blue Room / 17:00
Abstract:
The present cosmic mass density of possible-stable neutral heavy leptons is calculated in a standard cosmological model. In order for this density not to exceed the upper limit of 2*10^-29 g/cm^3, the lepton mass would have to be greater than a lower bound of the order of 2 GeV.

Quantum Information Journal Club: 'Onset of Ergodicity Across Scales on a Digital Quantum Processor'
2026-06-05 11:30 - 12:30 | Gray Room 3, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Title: ‘Onset of Ergodicity Across Scales on a Digital Quantum Processor’

Speaker: Marcos Crichigno (Phasecraft)

Venue & Time: Gray Room 3 / 11:30

Abstract: Boltzmann’s ergodic hypothesis lies at the foundation of classical statistical mechanics, yet its quantum counterpart remains far less understood. In this talk, I will discuss a quantum-information-theoretic measure of quantum ergodicity that probes its emergence at different resolution scales, revealing otherwise inaccessible global aspects of the quantum many-body wavefunction. We apply this metric to chart the boundary between ergodic and non-ergodic behavior in a two-dimensional disordered Floquet-Heisenberg system, using large-scale simulations, both classical and quantum on IBM’s latest digital quantum processor with up to 10×10 qubits

Quantum Information Journal Club: 'Exponential quantum advantage in processing massive classical data'
2026-06-08 11:30 - 12:30 | Gray Room 1, Instituto de Física Teórica, C/ Nicolás Cabrera 13-15, Cantoblanco, Madrid, Madrid, 28049, Spain
Title: ‘Exponential quantum advantage in processing massive classical data’

Venue/Time: 11:30 / Gray Room 1

Speaker: Isabel María Moreno Cuadrado (ICMAT) will present ‘Exponential quantum advantage in processing massive classical data’ by Hsin-Yuan Huang et al.

Abstract: Broadly applicable quantum advantage, particularly in classical data processing and machine learning, has been a fundamental open problem. In this work, we prove that a small quantum computer of polylogarithmic size can perform large-scale classification and dimension reduction on massive classical data by processing samples on the fly, whereas any classical machine achieving the same prediction performance requires exponentially larger size. Furthermore, classical machines that are exponentially larger yet below the required size need superpolynomially more samples and time. We validate these quantum advantages in real-world applications, including single-cell RNA sequencing and movie review sentiment analysis, demonstrating four to six orders of magnitude reduction in size with fewer than 60 logical qubits. These quantum advantages are enabled by quantum oracle sketching, an algorithm for accessing the classical world in quantum superposition using only random classical data samples. Combined with classical shadows, our algorithm circumvents the data loading and readout bottleneck to construct succinct classical models from massive classical data, a task provably impossible for any classical machine that is not exponentially larger than the quantum machine. These quantum advantages persist even when classical machines are granted unlimited time or if BPP=BQP, and rely only on the correctness of quantum mechanics. Together, our results establish machine learning on classical data as a broad and natural domain of quantum advantage and a fundamental test of quantum mechanics at the complexity frontier.

Holo-Club: 'Boundary entropy and entanglement phase transitions in holographic ICFTs'
2026-06-09 11:30 - 13:30 | Gray Room 3, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Title: Boundary entropy and entanglement phase transitions in
holographic ICFTs
Speaker: Evangelos Afxonidis (University of Oviedo)
Venue&Time: 11:30 / Gray Room 3
Abstract: In 1+1 dimensional conformal field theory with a boundary, the boundary contribution to the entanglement entropy is encoded in a single number g, effectively counting the boundary degrees of freedom. In contrast, for interface CFTs the corresponding quantity is a non-trivial function depending on the position of the interval relative to the interface, giving access to much more detailed information about the defect. In this talk, I will present several holographic examples illustrating the structure of this g-function and discuss the limit in which the entangling interval approaches the interface, relating it to the effective central charge. I will conclude with a discussion of entanglement phase transitions associated to bipartite entanglement in a variety of holographic interfaces.

Pheno Journal Club: 'Bubble Nucleation from Boson Star Collapse'
2026-06-11 12:00 - 13:00 | Grey Room 2, Instituto de Física Teórica, Madrid, Madrid, 28037, Spain
Title: Bubble Nucleation from Boson Star Collapse

Speaker: Kateryna Radchenko Serdula (IFT) will present “Bubble Nucleation from Boson Star Collapse”, 2511.21826

Venue&Time: Gray Room 2 / 12:00

Abstract: We present a new classical mechanism for nucleation of bubbles of true vacuum. The mechanism arises when dense boson stars form in the false vacuum. As the boson stars collapse due to attractive self-interactions, the field inside the star cores is enhanced beyond the potential barrier. Subsequently the stars explode as true vacuum bubbles and induce a cosmological phase transition. The mechanism raises the possibility that a vacuum that is stable against quantum tunneling can be vulnerable to “astrophysical” processes.

Seminar: 'Revisiting Critical Higgs Inflation: CMB Observables, Electroweak Couplings, and Perturbative Unitarity'
2026-06-11 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: Revisiting Critical Higgs Inflation: CMB Observables, Electroweak Couplings, and Perturbative Unitarity

Speaker: Sarah R. Geller (Yale U.)
Venue & Time: Red Room / 15:00

Abstract:
An intriguing and economical possibility to explain many cosmological observations is Higgs inflation, in which inflation is driven by the Standard Model Higgs with a non-minimal coupling to gravity. I will discuss near-critical Higgs inflation at two loops and show that, for any set of parameters derived from SM couplings at the electroweak scale and run to the inflationary scale, one can find a value of the non-minimal coupling that brings the model into compliance with all measured CMB observables. Unlike standard Higgs inflation, which typically requires unnaturally large values of the non-minimal coupling, I will demonstrate that in metric gravity we can match the CMB while staying within 3σ of electroweak precision data with non-minimal couplings on the order of 50–200. The success of the model, however, comes at the cost of self-consistency when it is treated as an effective description of electroweak-scale physics; that is, the model becomes unavoidably sensitive to physics beyond the SM in the UV, undermining the simplicity that originally motivated Higgs inflation.

Strings, Pheno and the Swampland (SPS) Journal Club
2026-06-18 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
Every Thursday at 12:00 in the Red Room.

Old Journal Club: 'Large scale perturbations in the open universe'
2026-06-18 17:00 - 18:00 | Blue Room, Instituto de Física Teórica (IFT) - C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Mikel Martin (IFT) will present “Large scale perturbations in the open universe”, by D. H. Lyth, & A. Woszczyna,
Venue&Time: Blue Room / 17:00
Abstract:
When considering perturbations in an open (Omega<1) universe, cosmologists retain only sub-curvature modes (defined as eigenfunctions of the Laplacian whose eigenvalue is less than -1 in units of the curvature scale, in contrast with the super-curvature modes whose eigenvalue is between -1 and 0). Mathematicians have known for almost half a century that all modes must be included to generate the most general HOMOGENEOUS GAUSSIAN RANDOM FIELD, despite the fact that any square integrable FUNCTION can be generated using only the sub-curvature modes. The former mathematical object, not the latter, is the relevant one for physical applications. The mathematics is here explained in a language accessible to physicists. Then it is pointed out that if the perturbations originate as a vacuum fluctuation of a scalar field there will be no super-curvature modes in nature. Finally the effect on the cmb of any super-curvature contribution is considered, which generalizes to Omega<1 the analysis given by Grishchuk and Zeldovich in 1978. A formula is given, which is used to estimate the effect. In contrast with the case Omega=1, the effect contributes to all multipoles, not just to the quadrupole. It is important to find out whether it has the same l dependence as the data, by evaluating the formula numerically.

Seminar: 'A hot take on electroweak skyrmions'
2026-06-23 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: ‘A hot take on electroweak skyrmions’
Speaker: Luis Gil (Universidad de Granada).
Venue&Time: Red Room / 15:00
Abstract: Skyrmions are stable and topologically non-trivial field configurations that behave like localized particles. They appear in the chiral effective theory for pions, where they correspond to the baryon states, and might also exist in the electroweak theory, in the presence of certain effective interactions.
In this talk, focusing on toy models that capture different limits of the electroweak sector of the Standard Model (SM), we will how skyrmions not classically stable at zero temperature can be stabilized by thermal effects. This motivates the study of skyrmions in the quantum effective action of the SM, where they might constitute a dark matter candidate without new physics.

Quantum Information Journal Club: 'Efficient Characterisation of Quantum Information Processors'
2026-06-24 11:30 - 12:30 | Gray Room 1, Instituto de Física Teórica, C/ Nicolás Cabrera 13-15, Cantoblanco, Madrid, Madrid, 28049, Spain
Speaker: Pablo Viñas Martínez (IFT)
Títle: ‘Efficient Characterisation of Quantum Information Processors’
Venue&Time: Gray Room 1 / 11:30
Abstract: “The precise characterisation and benchmarking of quantum information processors (QIPs) is essential for the development of quantum technologies. From the engineering of low-error physical components to the design of physically informed decoding strategies in quantum error correction (QEC), a detailed understanding of noise plays a central role. However, achieving an appropriate balance between the amount of information extracted and the experimental overhead required by characterisation protocols remains a significant challenge. In this talk, I will explore several approaches aimed at addressing this trade-off. First, I will discuss how the incorporation of physically motivated models can substantially reduce the resource requirements of quantum tomography protocols (https://arxiv.org/abs/2407.11539, https://arxiv.org/abs/2507.02542). Second, I will consider the problem from a complementary perspective: rather than focusing on the characterisation of fully general QIPs, I will examine protocols tailored to the characterisation of QEC circuits.”

Quantum Information Journal Club: 'Some Properties of Local One-Dimensional Hamiltonians'
2026-06-25 11:30 - 12:30 | Gray Room 1, Instituto de Física Teórica, C/ Nicolás Cabrera 13-15, Cantoblanco, Madrid, Madrid, 28049, Spain
Speaker: José Garre Rubio
Títle: ‘Some Properties of Local One-Dimensional Hamiltonians’
Venue&Time: Gray Room 1 / 11:30
Abstract: In this talk, I will discuss several properties of local Hamiltonians associated with the W state and matrix product states (MPS). I will begin by showing that the W state cannot be the unique ground state of any local Hamiltonian. I will then present a condition that guarantees that the parent Hamiltonian of an arbitrary MPS is well behaved, encompassing the W-state case as an example. Finally, I will characterize the action of local Hamiltonians on injective MPS, an important class that describes unique ground states. Throughout the talk, I will highlight several open problems and possible directions for future research. The results presented are based on [JGR, Quantum Information Processing 24, 366 (2025)], [JGR, A. Turzillo, A. Molnár, Annales Henri Poincaré 1–23 (2025)], and [JGR, A. Molnár, N. Schuch, F. Verstraete, arXiv:2603.28349].

Strings, Pheno and the Swampland (SPS) Journal Club
2026-06-25 11:30 - 12:30 | IFT Seminar Room/Red Room, Instituto de Física Teórica (IFT) -C. Nicolás Cabrera, 13-15, Fuencarral-El Pardo, Madrid, 28049,, Spain
Speaker: Alberto Castellano (Chicago U.)
Venue&Time: Red Room / 11:30

Seminar: 'Differential observables for the Higgs-strahlung process to all orders in EFT'
2026-06-25 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: ‘Differential observables for the Higgs-strahlung process to all orders in EFT.’
Speaker: Sourav Bera from Tata Institute of Fundamental Research (TIFR)
Venue&Time: Red Room / 15:00
Abstract: We develop methods to obtain the fully differential cross-section for the f f to Z(ll) h process to any desired order in effective field theory (EFT). To achieve this, we first derive a mapping between the partial wave expansion and the EFT expansion to all orders. We find that at lower orders, EFT predicts correlations between the different partial wave coefficients. This allows us to construct linear combinations of partial wave coefficients that get their leading contributions from a higher dimension EFT operator. We then introduce experimental observables, the so called angular moments — that probe these linear combinations of partial wave coefficients — and can be determined from a fully differential analysis of the angular distribution of the leptons arising from the Z – decay. We show that analysing the dependence of these angular moments on the Zh invariant mass allows us to systematically probe all higher dimension EFT operators contributing to this process. In particular, we discuss how our results can be used to probe dimension-8 operators in the Standard Model EFT (SMEFT). While we take the Higgs-strahlung process as an example, the methods developed here are completely general and can also be applied to other 2-to-2 collider processes.

Seminar: 'NLO Running in the SMEFT'
2026-07-02 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: ‘NLO Running in the SMEFT’
Speaker: Lukas Born (University of Bern).
Venue&Time: Red Room / 15:00
Abstract: The Standard Model Effective Field Theory (SMEFT) provides a systematic framework for parameterizing heavy new physics in a model-independent way. A central ingredient for precision analyses within this framework is the renormalization group equations (RGEs), governing the running of the Wilson coefficients across energy scales. Our recent computation of the two-loop β-functions in the SMEFT marks a milestone in this program, opening the door to genuine next-to-leading order (NLO) analyses.
In this talk, I will first discuss the key technical challenges we encountered in our calculation, how we addressed them by modifying the Warsaw basis, and the consistency checks on our results. Second, I will turn to a concrete phenomenological application, demonstrating that NLO running effects play an important role in Electroweak Precision Observables (EWPO).

Seminar: 'Sub-GeV Dark Matter, Neutrino Masses, and Astrophysical Signals from a Rich Dark Sector'
2026-07-07 15:00 - 17:00
Title: ‘Sub-GeV Dark Matter, Neutrino Masses, and Astrophysical Signals from a Rich Dark Sector.’
Speaker: Elina Merkel (University of Bologna)
Venue&Time: Red Room / 15:00
Abstract: Rich dark sectors provide an attractive framework for addressing several puzzles in particle physics and cosmology within a single model. In this talk, I will present a simple sub-GeV dark-sector realization featuring a dark matter candidate, a light scalar mediator, and an extended neutrino sector. I will show how the model can reproduce the observed relic abundance, generate light neutrino masses, and satisfy cosmological constraints. I will then discuss its phenomenological implications, focusing on neutrino signals that could be probed by current and future neutrino telescopes.
