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Jury Prof. Yves CAUDANO (UNamur), chairmanProf. André FÜZFA (UNamur), secretaryProf. Dominique LAMBERT (UNamur)Dr. Jérémy REKIER (Observatoire royal de Belgique et UCLouvain)Prof. Dr. Félix FINSTER (Regensburg University) Summary Sounding the Universe with a relativistic solar sailboat or Einstein-Dirac fermionsThe Universe exerts a curiosity on man that is both undeniable and fundamental. To unravel the mysteries of the Cosmos, man is driven to develop two major investigative strategies: direct exploration by sending space probes, and indirect exploration by observing cosmic electromagnetic fields, gravitational waves or particles such as fermions.Following these two strategies, in this thesis we develop, in the first approach (consisting of sending a space probe), a relativistic kinematic and dynamical model of photonic sails (light sails) with arbitrary reflectivity and absorbance, moving in a non-rectilinear manner with the aim of exploring interstellar space. The problem is to determine the sail's trajectory in a Minkowski spacetime, a four-dimensional variety. From detailed calculations, we obtain the sail's universe line in the laser reference frame as a function of the sail's proper time.The second approach applies the Two-State Vector Formalism and weak measurements to a homogeneous, isotropic cosmological framework. By coupling Dirac spinners to classical gravity, we calculate weak values of the energy-impulse tensor, the Z component of spin and pure states. Extending the work of Finster and Hainzl on Einstein-Dirac cosmology, we show that the accelerated expansion of the Universe can be interpreted as a consequence of post-selection. We also demonstrate that weak measurements can amplify signals using simpler equipment, thanks to judicious selection of the initial and final state vectors. In addition, this procedure highlights certain geometric properties of the Cosmos' three-dimensional space, offering a new way of exploring the structure of the Universe.We also examine the mathematical structure on which the Dirac equation rests beyond the usual dimension and signature. This reveals a rich internal symmetry and gives rise to a particularly aesthetic diagrammatic representation. Abstract Probing the Universe with a Relativistic Light Sail or Einstein-Dirac FermionsHumanity's profound curiosity about the cosmos is both undeniable and fundamental. To demystify the Universe, humankind is compelled to develop both direct and indirect probing strategies: direct exploration through physical visits using probes, and indirect exploration by observing cosmic electromagnetic field, gravitational waves and particles such as fermions.Building on these two strategies, this thesis proposes two distinct approaches to probing the Universe. In the first approach, we present a relativistic kinematic and dynamic model of light sails with arbitrary reflectivity and absorptance, undergoing non-rectilinear motion as a method of interstellar exploration. The problem involves solving for the trajectory of the sail in a 4-dimensional Minkowski spacetime manifold. By detailed computation, we derive the worldline of the sail in the laser's frame in the sail's proper time.The second approach applies the Two-State Vector Formalism and weak measurements to a spatially homogeneous and isotropic cosmological framework. Coupling Dirac spinors with classical gravity, we compute weak values of the energy-momentum tensor, the Z-component of spin, and pure states. Extending the work of Finster and Hainzl on Einstein-Dirac cosmology, we demonstrate that the Universe's accelerated expansion can be interpreted as a consequence of post-selection. We also show that weak measurements can amplify signals with simpler equipment by carefully selecting initial and final state vectors. This process also reveals geometric properties of the spacelike three-manifold of the Cosmos, opening new way on probing the structure of the Universe.We explore also the mathematical framework underlying the Dirac equation beyond the standard dimension and signature. This enterprise reveals its symmetrically rich properties and aesthetic diagrammatic representation.

This seminar is aimed at researchers as well as (future) childcare professionals - educators, carers, childcare workers - who wish to question this issue and equip themselves to better listen to and include young children. Thanks to an interdisciplinary, cross-border approach, experts from the fields of psychology, pedagogy, law and the human sciences will share their knowledge and experience. This time of exchange will provide a better understanding of how to foster children's information and participation by adapting to their abilities and needs. Registrations Read more

A drink will be organized following the lecture.This lecture is proposed by "Kàp to UNIVERSEH", the kot-free space popularization project of the University of Namur, and Local Student Club of UNIVERSEH.When: Wednesday, February 26, 2025 at 7pmWhere: Faculty of Sciences - Auditorium S01Free I want to register

The 24th edition of Printemps des Sciences was held from March 24 to 30 throughout Wallonia and Brussels, on the theme of "Eau-rêka". The aim of this annual event is to make science and technology accessible to as many people as possible. Mission accomplished for this new edition!

The 11th edition of the Ma Thèse en 180 secondes competition was held this Friday, March 28, 2025 at the Faculty of Science. Three biologists will represent UNamur at the Belgian final, to be held in Mons on May 21.

How can we better understand the landscape around us? For over ten years, UNamur has been offering continuing education in landscape analysis. What does this concept involve? What are its objectives? And how is landscape analysis practiced? Answers with Corentin Fontaine, Coordinator and Trainer for "Les Ateliers du Paysage" organized by UNamur's center for continuing education in science and mathematics (CeFoSciM).

A delegation from the Université de Namur took part in an exploratory mission to the Université Cheikh Anta Diop (UCAD) in Dakar, Senegal. The aim: to discover the research carried out in the field, meet UCAD researchers and initiate future collaborations between the two institutions.

Statistics usually focus on anticipating events that fall within the norm. But what about rare events? They are dealt with by a branch of mathematics called extreme value theory, in which Anna Kiriliouk, lecturer in statistics at UNamur, is a specialist. Applied to the climate, this theory enables us to better predict extreme climatic events, at a time when these are multiplying due to climate change.

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Gabriel Dias De Carvalho Junior adds his expertise in didactics and cognitive psychology to the physics didactics research unit of UNamur's Department of Physics. With almost two decades of teaching experience in Brazil, he works to improve teaching practices. His innovative projects aim to make teaching more inclusive and accessible, while establishing international collaborations.

An astrophysics expert, Professor André Fűzfa (Faculté des sciences, Institut Naxys) also harnesses his scientific knowledge to take everyone on a journey into the world of the imagination, through literature. Finding Ganymede is his new novel, co-created with illustrator Fabrice Rasir, an alumnus of the Mathematics Department. A book that incorporates images generated by artificial intelligence (AI). The novel is thus a skilful blend of graphic AI, physics and fiction that helps stimulate the imagination while providing an instructive dimension.

The conference is co-organized by the University of Namur, Belgium and Wuhan University of Technology, China and supported by Foshan Xianhu Laboratory and other organisms.More info on the GCMC2025 website...