Tailored light excitation and nonlinear control of lattice vibrations have emerged as powerful strategies to manipulate the properties of quantum materials out of equilibrium. Generalizing the use of coherent phonon-phonon interactions to nonlinear couplings among other types of collective modes would open unprecedented opportunities in the design of novel dynamic functionalities in solids. For example, the collective excitations of magnetic order –magnons– can carry quantum information with little energy dissipation, and their coherent and nonlinear control would provide an attractive route to achieve collective-mode-based information processing and storage in forthcoming spintronics and quantum information science.

In this talk, I will show that intense terahertz (THz) fields can initiate processes of magnon up-conversion and magnon mixing mediated by an intermediate magnetic resonance. By using a suite of advanced spectroscopic tools, including a newly demonstrated two-dimensional THz polarimetry technique, we unveil these anharmonic magnon coupling phenomena in a canted antiferromagnet. These results demonstrate a route to inducing desirable energy transfer pathways between coherent magnons in solids and pave the way for a new era in the development of ultrafast control of magnetism.

Understanding how complex ecological communities function, persist, and adapt is one of the grand challenges of contemporary science. Ecosystems involve interactions among countless organisms, each responding to a constantly changing environment. Yet, despite this apparent complexity, ecological systems often display strikingly regular, robust, and universal patterns.
This talk discusses how tools from statistical physics, complex systems theory, and effective modelling enable us to uncover the emergent properties of ecological communities and to bridge the gap between microscopic dynamics and macroscopic phenomena. The aim of the talk is to convey how a physics perspective can provide unifying principles for ecology, and how theoretical insights, when combined with data, can deepen our understanding on diversity and dynamics of ecological systems.

We will speculate on the novel concept of mereological quantum phase transition (m-QPTs). Our framework is based on generalized tensor product structures (g-TPS), a parameter-dependent Hamiltonian, and a quantum scrambling functional. By minimizing the scrambling functional, one selects a g-TPS, enabling a pullback of the natural information-geometric metric on the g-TPS manifold to the parameter space. The singularities of this induced metric in the thermodynamic limit characterize the m-QPTs. We will illustrate this framework through analytical examples involving quantum coherence and operator entanglement Ref: https://arxiv.org/abs/2510.06389 <https://arxiv.org/abs/2510.06389>

The intersection between Nuclear and Particle Physics and Medical Diagnosis and Therapy represents one of the most significant areas of innovation in applied science. While often unseen by the patient, technology based on nuclear phenomena is a crucial component of modern medicine.
This seminar will explore the essential and dynamic role of nuclear physics within the hospital environment. We will address fundamental questions that connect basic research to clinical applications: In what ways do radiations emitted by unstable nuclei facilitate the diagnosis of complex pathologies? What is the function of antimatter in modern imaging methods (such as PET)? How can nuclear decays and the use of heavy ion beams (hadron therapy) be engineered for the targeted treatment of tumors, improving therapeutic efficacy while reducing damage to healthy tissues?
The colloquium aims to unveil this scientific connection, often overlooked, between the world of fundamental physics research and the clinical infrastructure, tracing a path from the accelerator laboratory to the delivery of advanced therapies in oncological treatment centres.

No experiment today provides evidence that gravity requires a quantum description. The growing ability to achieve quantum optical control over massive solid-state objects may change that situation -- by enabling experiments that directly probe the phenomenology of quantum states of gravitational source masses.
This can lead to experimental outcomes that are inconsistent with the predictions of a purely classical field theory of gravity. Such “quantum Cavendish” experiments require to explore extreme regimes of both quantum and gravity phenomena, specifically: delocalised motional quantum states of sufficiently massive objects, as well as gravity experiments on the microscopic scale. This seminar reviews the current status in the lab and the challenges to be overcome for future experiments.

Looking at the starry sky, several questions come to our mind, such as "What is the Universe made of?", "How was it created?", "What, if anything, happened before the Big Bang?", "How does the Universe evolve and what is its ultimate fate?". To address these puzzling questions, we need a blend of theoretical developments and observational data. This seminar will discuss the observational and experimental tools we have at our disposal, as well as the two pillars of theoretical physics, namely General Relativity and Quantum Mechanics. Our current understanding of the early universe will be discussed, and the need for a fundamental theory, dubbed Quantum Gravity, will be highlighted, in order to resolve the remaining open questions.

International security and peace are very serious concerns in these days full of conflicts and marked by unpredictable political, economic and social changes. The role science can play in such a tensed global scenario is a complex one. Beside the contribution it can give to promoting dialogue and peace, it can also make available knowledge and instruments that may be used to offend, ranging from application of AI for new kinds of armaments to the development of even more destructive nuclear weapons. Since its creation the Pugwash institution, which earned the Nobel Peace Prize in 1995, is very active to “develop and support the use of scientific, evidence-based policymaking, focusing on areas where nuclear and mass destruction weapons risks are present”. Participating remotely via videoconference, Karen Hallberg, the present Secretary General of Pugwash, will present an overview of Pugwash’s action, with focus on the most critical topics the organization is presently dealing with and on the solutions it proposes to reduce global security threats and the danger of armed conflicts. The presentation is in the context of the course “Sciences, diplomacy and policymaking for a sustainable future” given by Maurizio Bona, who will initiate and moderate a dialogue with Karen Hallberg after her presentation, with the participation of the audience.

The study of habitable worlds has become a central focus in modern astrophysics, propelled by the discovery of exoplanets, the search for life beyond Earth, and the quest to understand the conditions necessary for supporting life. This colloquium will provide an overview of the current state of the art in this highly interdisciplinary field, emphasising the intricate balance of factors that determine planetary habitability. Key physical principles such as stellar properties, atmospheric composition, climate dynamics, and the influence of galactic environments will be discussed, along with the methods used to assess and characterize these conditions across a range of exoplanets.