Grad School Physics Seminar 2025/26

Name: Grad School Physics Seminar 2025/26
Start: 2025-10-02T09:15:00+02:00
End: 2026-06-26T18:00:00+02:00
Location: NCBJ

2 Oct 2025, 09:15 → 26 Jun 2026, 18:00 Europe/Warsaw

Room 207 (NCBJ)

Room 207

NCBJ

Pasteura 7

Description

Physics seminar of the Graduate School of NCBJ.

GoToMeeting link for the seminar: https://app.gotomeeting.com/?meetingId=434622613

Thursday, 9 October
- 09:15 → 09:35
  
  Welcoming Talk of the Graduate School Director¶ 20m
  
  Speaker: Prof. Michał Spaliński
- 09:35 → 09:55
  
  Discussion about the goals and organization of the PhD seminar¶ 20m
  
  Speakers: Anna Durkalec (National Centre for Nuclear Research), Jakub Wagner (National Centre for Nuclear Research), Michal Bluj (NCBJ)
  
  PHD SEMINARS.pdf
Thursday, 16 October
- 09:15 → 09:35
  
  Production of Self Interacting Scalars in the Early Universe 20m
  
  In this talk, I will present an overview of my research on Dark Matter (DM). I will begin with a brief introduction to the study of DM across different approaches, before focusing on Cannibal DM produced via the freeze-in mechanism in the early Universe. I will discuss the non-trivial thermal dynamics of this scenario and the importance of tracking the DM temperature evolution. I will then outline the resulting detectability prospects, which become viable in non-standard cosmological histories, particularly when the early Universe is dominated by a cold inflaton field. In the second part, I will turn to cosmological phase transitions, emphasizing how first-order transitions can generate observable gravitational waves (GWs). Finally, I will show that an inverse phase transition can occur within the freeze-in framework, where cannibalization dynamics crucially modify the evolution of the transition and the associated GW phenomenology, potentially within reach of future interferometer experiments.
  
  Speaker: Juan Esau Cervantes Hernandez (NCBJ Warsaw)
  
  dyskusja_phd_seminarium.pdf Self_Interacting_Scalars-EsauCervantes.pdf
Thursday, 23 October
- 09:15 → 09:35
  
  Study of direct photon production in Pb-Pb collisions at $\sqrt {s_{NN}}$ = 5.02 TeV with ALICE experiment’s Photon Spectrometer (PHOS) at Large Hadron Collider 20m
  
  The Quark-Gluon Plasma (QGP), a state of deconfined quarks and gluons, is believed to have existed in the early Universe shortly after the Big Bang. As the QGP cools, it transitions into the hadronic matter we observe today. In laboratory settings, small-scale "Big Bangs" are created through high-energy heavy-ion collisions, which heat the hadronic matter above the transition temperature, approximately 150 MeV, resulting in the formation of the QGP. Direct photons serve as unique probes in high-energy proton-proton and nucleus-nucleus collisions due to their weak interaction with the dense and hot quark-gluon medium. These photons escape the medium unaltered, providing undistorted information about the collision's evolution.
  In the ALICE experiment at the Large Hadron Collider (LHC), photons from lead-lead collisions are measured using techniques such as the Photon Conversion Method and Electromagnetic Calorimeter. The Photon Spectrometer (PHOS), offering high-precision photon detection, was used for our analysis (with Run 2 data in Pb-Pb collisions at $\sqrt {s_{NN}}$ = 5.02 TeV) to measure inclusive photons and simulate decay photons, aiding in the derivation of direct photon spectra. By disentangling the contributions of decay, prompt and thermal photons emitted during these collisions, we can estimate the effects of cold and hot nuclear matter and gain insights into the temperature, correlations, and collective phenomena within the QGP.
  
  Speaker: Sushobhan Mandal (NCBJ)
  
  Direct_photon_SM_23Oct25.pdf
Thursday, 30 October
- 09:15 → 10:15
  
  CMB Lensing with TEReSiTA 1h
  
  We are currently living in the most scientifically active era of the human kind: cosmology makes no exception. Our understanding of the Universe has radically changed during the last decades. However, while many long-standing questions about the nature of the Universe have been answered, many others have emerged. Why is the Universe's expansion accelerating? What is dark energy? What is dark matter? How does inflation work?
  The study of the Cosmic Microwave Background, together with other cosmological probes, is one of the ways we can answer these new questions. In particular, studying the weak gravitational lensing effect of large-scale structure on the CMB photons, we can obtain information about both the primordial and the late-time Universe. I will show how.
  In this talk, I present the Tomographic Ensamble of Realistic Simulations of Tracers and Anisotropies (TEReSiTA): a set of simulations of correlated galaxy catalogues and CMB observations. TEReSiTA, my original work, is a very useful and versatile tool for testing new paths in the quest for high-precision cosmological parameter estimation.
  
  Speaker: Nicola Principi (NCBJ)
  
  principi_phd_seminar.pdf
Thursday, 6 November
- 09:15 → 10:15
  
  From gravitational symmetries to the area law 1h
  
  The complete structure of quantum gravity remains unknown to this day. A recent line of research proposes using the symmetries of gravity as a guiding principle in the search for its quantum formulation. In this talk, I will present our approach, which employs these symmetries to classify the possible quantum gravitational states associated with a subregion of spacetime. I will further show that our formalism naturally leads to a computation of the entanglement entropy of such subregions. Finally, I will argue that, in the classical limit, the leading term of this entanglement entropy scales with the area of the subregion’s boundary, thus recovering the famous Bekenstein–Hawking area law and strengthening the case for a symmetry-based approach to quantum gravity.
  
  Speaker: Ludovic Varrin
  
  From Gravitational Symmetries to the Area Law.pdf Graduateseminar2025.odp
Thursday, 13 November
- 09:15 → 10:15
  
  Ultra-Diffuse Galaxies study 1h
  
  Low Surface Brightness Galaxies (LSBGs) are defined as galaxies with an average central surface brightness, 𝜇(0,r), below the typical level of the night sky. LSBGs are estimated to contribute less than 1% to the luminosity of the local observable universe; however, their contribution to the total number density of galaxies is estimated to be around 40% to 50%. Exploring the standard evolution of LSBGs and investigating the reasons behind their faint nature could be crucial to understanding our universe. Among LSBGs, a subsample of objects has been identified: classified as Ultra Diffuse Galaxies (UDGs), which are LSBGs having a central surface brightness measured in g-band, 𝜇(0,g), larger than 24 mag per arcsec² and an extended half-light radius, r{1/2}, larger than 1.5 kpc. UDGs populate the distribution tail of the LSBGs' luminosity profile, inhabiting field, group and cluster environments. Previous studies have established substantial differences in the properties of UDGs according to their host environment. Comparing properties in different UDGs hosting environments would allow us to find the most likely evolutionary path of these galaxies, factoring out the episodic events due to their surroundings. In our work, we validated the performance of a Machine Learning model developed to find LSBGs and UDGs, extracting also physical properties of LSBGs/UDGs through redshift measurements such as star formation rates (SFRs) and stellar masses(Mstar).
  
  Speaker: Antonio Vanzanella (National Centre for the Nuclear Research, Pasteura 7, 02-093 Warsaw, Poland)
  
  Seminar.pdf
Thursday, 20 November
- 09:15 → 10:15
  
  Multidimensional Framework for Modeling Fusion and Fission of Heaviest Nuclei 1h
  
  This work presents the development of a comprehensive computational framework for modeling fusion and fission processes in heavy and superheavy nuclei (Z ≥ 90). The framework is based on the Warsaw Macroscopic-Microscopic Model (WMMM), extended to incorporate multiple shape parameterizations, including the traditional beta parameterization and the Fourier-over-Spheroid (FoS) approach, which enables description of nuclear shapes from compact configurations to scission.
  
  The framework combines several methodological advances in shape parameterization conversion, model modernization, and large-scale computational capabilities to generate multidimensional potential energy surfaces spanning over 100 million configurations per nucleus. Stochastic shape evolution is described through both simplified and sophisticated formalisms, enabling predictions of fusion probabilities, ground state properties, fission barriers, and mass fragment distributions. Applications to superheavy elements and actinide systematics demonstrate the framework's ability to reproduce experimental observables without parameter fitting, suggesting promising prospects for a unified theoretical description of fusion-fission dynamics across the heavy element region.
  
  Speaker: Mr Aleksander Augustyn (NCBJ)
  
  AAugustyn_Seminar_201125.pdf
Thursday, 27 November
- 09:00 → 10:00
  
  Probes of light dark matter in relativistic regime 1h
  
  Dark matter interactions are traditionally probed in the non-relativistic regime characteristic of cold DM in the present-day universe. However, this strategy is insufficient for probing a class of important thermal DM targets for which non-relativistic scattering rates are highly suppressed. This opens an unexplored region of parameter space and motivates the development of detection strategies specifically tailored to low-mass dark matter. In this talk, I will discuss examples of such models and outline novel detection strategies designed to probe them — either directly, or indirectly through the detection of light dark-sector mediators.
  
  Speaker: Jyotismita Adhikary (NCBJ)
  
  NEW_Grad_Sem_Jyotismita-6.pdf

Grad School Physics Seminar 2025/26

Room 207

NCBJ

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