Physics PhD Research Day 2026 - UniTS

Thursday 28 May 2026, 09:00 → 18:00 Europe/Rome

Physics PhD Research Day 2026

28th May 2026

Physics Department, University of Trieste, lecture room A

 

The Research Day, in its inaugural edition, is a workshop intended to showcase the state-of-the-art research carried out at the Department of Physics through presentations delivered by the second-year PhD students of the PhD Course in Physics.

In the coming years, the workshop will cyclically cover all the main research areas active within the Department, thus offering a broad overview of the scientific activities carried out by its research community.

The programme will also include a poster session by first-year PhD students, who will present their new research projects.

The entire physics community is warmly invited to attend. In particular, Master’s students in Physics are strongly encouraged to participate, as the workshop represents an excellent opportunity to learn about the research conducted at the Department and to become acquainted with its main scientific directions.

Please register via the following link by May 15th: https://forms.gle/PW2Lr7TEqoVBgJhf6

Welcome

Conveners: Angelo Bassi (University of Trieste and INFN), Giacomo Contin (University of Trieste and INFN), Giuseppe Della Ricca (Istituto Nazionale di Fisica Nucleare)

Morning 1

Convener: Michela De Col

1 Supermassive Black Holes: "camels" in the Sky

Supermassive black holes can power some of the brightest and most energetic sources in the Universe. In Active Galactic Nuclei (AGNs), matter accreting onto the central black hole can launch relativistic jets whose emission is observed across the entire electromagnetic spectrum, from radio waves to gamma rays.

A useful way to visualize their broadband emission is through the characteristic two-hump shape of the spectral energy distribution, making some AGNs look like a "camel" in the sky.

In this talk, I will introduce how multiwavelength observations help us investigate the physical processes taking place in AGN jets, with a particular focus on the role of the Fermi-LAT space telescope in studying their gamma-ray emission.

Speaker: Ermes Aviano (Istituto Nazionale di Fisica Nucleare)

2 Strangeness production in jets and in the underlying event in OO collisions with ALICE and tuning of hadronization models

The aim of my PhD research is to investigate strangeness production within jets originating from strange quarks (s-jets) in proton-proton (pp) collisions at $\sqrt{s}=13.6$ TeV, as well as in jets and in the underlying event (UE) in OO collisions, using data from the ALICE experiment at LHC. A key objective is to disentangle perturbative and non-perturbative hadron production mechanisms by studying their relative contributions in the UE and within jets. This work focuses on assessing the specific contributions of jets and the UE to strangeness enhancement as a function of multiplicity, a distinction that has not yet been extensively explored.

The work is structured into three parts. First, s-jet tagging is performed using machine learning techniques trained on Monte Carlo (MC) simulations. Unlike well-established heavy-flavor tagging ($b$, $c$), identifying s-jets remains a significant challenge due to absence of characteristic secondary vertex signatures typical of heavy flavors and the similarity to light-flavor jets ($u$, $d$, $g$). This work explores how to address these challenges using a graph neural network (GNN). Results from the training highlight the ongoing challenges in discriminating these jets.

Second, since MC models are essential for understanding strangeness production mechanisms, this work investigates production in pp collisions using the PYTHIA 8 event generator. Specifically, the tuning of two hadronization models---Rope Hadronization and Closepacking---is performed, with the ultimate goal of testing strangeness production within jets.

Finally, a study of strange hadron production in OO collisions at $\sqrt{s_{\mathrm{NN}}}=5.36$ TeV is presented. This new collision system offers unique insights into particle production processes, enabling a direct comparison with ongoing studies in pp collisions. Notably, this research constitutes the first-ever measurement of these observables in OO collisions, providing a crucial bridge between small and large collision systems.

Speaker: Lorenzo Bernardinis (Istituto Nazionale di Fisica Nucleare)

3 Gravitational Waves: Why They Matter and How We Study Weak Signals

Gravitational waves provide a unique way to study some of the most extreme phenomena in the Universe, offering access to astrophysical processes that may be hidden or only partially visible through traditional electromagnetic observations. Their observation has already transformed modern astrophysics, and future progress will depend not only on detector sensitivity, but also on our ability to extract information from weak, uncertain, or poorly modeled signals. In this presentation, I will first outline why gravitational-wave research is important today, from a physical, astrophysical, and methodological point of view. I will then present my recent PhD work, which focuses on the study of subthreshold gravitational-wave candidates and on the development of tools to account for detector response, sky localization, and statistical biases in population analyses. These activities include the use of statistical tests applied to sky distributions of candidate events and broader studies of network performance for present and future interferometers. I will also briefly discuss related work on PycWB, a modern and modular framework for unmodeled gravitational-wave searches.

Speaker: Davide Di Piero

Coffee break / Poster session

Morning 2

Convener: Samuele Cattaruzzi (Istituto Nazionale di Fisica Nucleare)

4 Deep Generative Priors for Interferometry: Non-Parametric Forward Modeling of the Sunyaev-Zeldovich Effect

Modern astrophysics relies on high-fidelity hydrodynamical simulations to study complex baryonic physics. In this talk, I will show how it is possible to use these tools to solve complex inverse problems, such as interferometric observations of the thermal Sunyaev-Zeldovich (tSZ) effect. Specifically, I will present how Generative Machine Learning tools can be implemented in a Simulation-Based Inference (SBI) framework when trained to reproduce simulations. I will compare Generative Adversarial Networks (GANs), Diffusion Models, and Flow Matching, trained on tSZ maps from multiple cosmological suites. Moving beyond standard computer vision metrics, we evaluate these architectures on their physical fidelity, training stability, and generalization capacity, demonstrating how deep generative priors can robustly solve complex inverse problems in physics.

Speaker: Luca Fontana

5 Electron and Hole Dynamics in MoS2 probed by Time- and Angle-Resolved Photoemission Spectroscopy

Transition metal dichalcogenide (TMD) semiconductors exhibit strong light-matter interaction and tunable optical and electronic properties, whose control requires the understanding of the system response to an optical excitation. Here, we investigate electron and hole population and relaxation dynamics in bulk and monolayer MoS₂ using time- and angle-resolved photoemission spectroscopy (TR-ARPES). The measurements, performed at the SPRINT laboratory, provide energy, momentum, and time resolution suitable for probing ultrafast carrier dynamics following photoexcitation, in the whole Brillouin Zone.
Bulk and monolayer samples are excited with 1.94 eV and 1.85 eV pump pulses, respectively, and probed with a 26.4 eV pulse from High Harmonic Generation. The dynamics of hot electrons in the conduction band and holes in the valence band are analyzed and compared to identify signatures of many-body effects, including band-gap renormalization at short pump-probe delays. The evolution of the momentum distribution curves in conduction band is also examined. We observe an unexpected energy broadening and shift of the conduction band in monolayer MoS₂, which cannot be explained by direct optical transitions induced by the pump or by multiphoton absorption processes. Two possible mechanisms are considered: defect-assisted Auger-like processes and band-gap renormalization.

Speaker: Sara Dottorini

6 Giraldin Carlo

7 AGN kinetic feedback in OpenGadget3

AGN feedback is an essential component of cosmological simulations, required to quench star formation in central galaxies and regulate black hole growth. Recent simulations such as Illustris or the RAFIKI suite have shown the important impact of kinetic feedback modeling the activity of AGN at low accretion rates. In this talk, I will present the latest results of the new kinetic feedback implementation in the OpenGADGET3 code.

Speaker: Maxime Gitton

12:35 Lunch break

Afternoon 1

Convener: Roberto Ingrao

8 Using AI to Detect High-Redshift Gamma-ray Bursts Afterglows with Fermi-LAT

The detection of high-redshift (high-z) Gamma-ray Bursts (GRBs) can significantly improve our understanding of the early Universe by providing tighter constraints on cosmological parameters and valuable insights into the formation of the first stars and galaxies. However, detecting them in gamma-rays is challenging due to the sensitivity of current telescopes in this energy range. This contribution will provide an overview of the theoretical and observational properties of GRBs, with particular focus on high-z events, and present a data-driven methodology based on Artificial Intelligence techniques developed within my PhD project to identify faint high-z GRB afterglow signals in Fermi-LAT data, with a focus on the 100 MeV–1 GeV energy range.

Speaker: Riccardo Martinelli (Units)

9 Curvature-Induced Faceting of hBN on Platinum: A DFT and Machine-Learning Study

Experiments show that when a layer of hexagonal boron nitride (hBN) is grown on a curved platinum substrate, it induces a faceting process that creates stable facets, where hBN exhibits distinct electronic properties. Thus, the precise control of the curvature geometry in 2D materials can redefine this material family. However, the underlying mechanisms for faceting are not yet fully understood. To understand the curvature-induced effect, we first performed Density Functional Theory (DFT) calculations, and to capture the dynamics of the faceting mechanism, we employed an Atomic Cluster Expansion (MACE) interatomic potential. hBN adsorption is studied across nine Pt facets — Pt(111), Pt(443), Pt(553), Pt(221), Pt(331), Pt(441), Pt(881), Pt(991), and Pt(110) — using low-mismatch structural models constructed for each surface to minimize artificial strain effects. The DFT results reveal a consistent and physically meaningful trend. Experimentally stable facets bind hBN more strongly than their unstable counterparts. Pt(110) exhibits the strongest adsorption at 0.625 eV/BN, followed by Pt(221) at 0.373 eV/BN, Pt(881) at 0.285 eV/BN, and Pt(441) at 0.232 eV/BN. In contrast, the unstable facets bind more weakly: Pt(331) at 0.183 eV/BN, Pt(443) at 0.181 eV/BN, and Pt(553) at 0.160 eV/BN. Pt(991), at 0.216 eV/BN, represents a borderline case between the two groups. Structurally, hBN on unstable facets shows more pronounced bending near step-edge regions, indicating poorer registry with the underlying Pt surface. To move beyond static energetics, a MACE interatomic potential was trained on DFT energies and forces using an active-learning pipeline. Force root-mean-square error (RMSE) improved from 50.1 meV/Å in the baseline model to 29.3 meV/Å in the final model, while the energy RMSE converged to 6.6 meV/atom. The resulting potential performs reliably across near equilibrium hBN/Pt configurations. Overall, the results establish a consistent picture in which stronger hBN–Pt interaction correlates with experimental facet stability. Future work will extend the training dataset through an AiiDA-based active-learning workflow, incorporating height scans, lateral registry shifts, and atomic displacements across all facets. This will enable large-scale molecular dynamics (MD) simulations to directly capture the dynamic faceting mechanism.

Speaker: Mahmood Muhammad Saad

10 Life in five dimensions

One of the many unexpected byproducts of String Theory is the discovery of interesting, interacting Quantum Field Theories in a five-dimensional spacetime. In this talk I will discuss differences and analogies with the four-dimensional world, focusing in particular on gauge theories. These theories admit a universal U(1) symmetry, that is the five-dimensional incarnation of the theta-term of four-dimensional gauge theories. I will present novel results on the action of such symmetry on extended operators, associated to magnetically charged excitations analogous to magnetic monopoles.

Speaker: Antonio Santaniello

11 Sbernadori Sara

Coffee break / Poster session

Afternoon 2

Convener: Giuseppe Troian

12 Sgatti Lapo

13 Cannito Stefano

Speaker: Stefano Cannito (Istituto Nazionale di Fisica Nucleare)

14 Interacting Topological Phases and Neural Network Quantum States

The Landau paradigm has been highly successful in understanding and classifying phases of matter through symmetry breaking and local order parameters. However, some quantum phases cannot be fully characterized within this framework, as their defining properties are topological rather than local. A paradigmatic example is the fractional quantum Hall effect, a strongly correlated phase where topology and interactions lead to exotic properties, such as quasiparticles carrying fractional charge and obeying neither bosonic nor fermionic statistics.

In this talk, I will use the fractional quantum Hall effect as an example to introduce topological phases. I will then present the Bose–Hofstadter model, a two-dimensional lattice system of interacting bosons exhibiting fractional quantum Hall physics. Finally, I will discuss how we can study such quantum many-body systems numerically, in particular how neural networks can be used as variational wave functions to approximate their ground states, with an emphasis on the Bose-Hofstadter case.

Speaker: Francesco Tognocchi

15 Beyond Groups: Non-Invertible Symmetries and Fusion Categories

Symmetries play a fundamental role in modern physics, from condensed matter physics to quantum field theory. The traditional description in terms of groups, however, does not exhaust the richness of the symmetric structures that can be present in a physical system. In this talk we will explore these possibilities by introducing the concept of non-invertible symmetry, in which symmetry operators are described not by the elements of a group, but by objects of a "fusion category". Considering 2d systems, a graphical notation will be used to represent these operators as lines in spacetime, and we will discuss how these can fuse in different ways, giving rise to the structure of F-symbols. The latter constitute the fundamental data that completely characterise the category — and therefore the symmetry of the physical system.

Speaker: Massimo Zorzenon

Close-up