Colloqui di Dipartimento / Physics Colloquia

412C (Room)



Stefania Vecchi (Istituto Nazionale di Fisica Nucleare)
    • 1
      GRB221009A, the brightest gamma-ray burst ever or: how I started worrying about cosmological explosions

      On October 9, 2022, the Earth was flashed for ten minutes by GRB221009A, the brightest and one of the longest gamma-ray bursts yet observed since the birth of gamma-ray astronomy 50 years ago. The gamma-ray (keV to MeV energy band) flux was so intense that it saturated almost all of the detectors aboard a number of space missions. Remarkably, it caused a sudden ionospheric disturbance in the lower layers of the Earth's sunlit ionosphere (60-100 km in altitude): this is exceptional for a source that lies two billion light-years away from us. Had it gone off in the centre of our Galaxy (at ~30 thousand light-years from us), it would have probably caused a mass extinction on Earth. The exceptional nature of this event was the result of two rare properties: (i) intrinsically very luminous and energetic (among the top 1% of all times) and (ii) relatively close to us (among the 4% nearest ones out of ~600 events with measured distance). The estimated rate of comparably bright bursts is about one in a few (1 to 5) centuries. The gamma-rays were produced by a massive star, whose core collapsed to a black hole, which in turn developed a relativistic jet pointed towards us, and whose energy was (partly) dissipated into the gamma-rays that flashed us two billion years later. Many very-high energy photons (>100 MeV) were detected from GRB221009A, with >5000 photons with energy beyond 500 GeV all the way up to the most energetic photon yet observed from a GRB with an energy of 18 TeV half an hour after the GRB. These observations set important constraints on the extreme acceleration processes produced by these relativistic shocks. In addition, the observation of a 18-TeV photon from a source at cosmological distance, thus escaping pair creation along the way, sets important constraints on the diffuse background light and on possible new physics. In this talk I explain how the study of this event can help shed light on the secrets of these mind-boggling cosmological explosions that are still shrouded in mystery and whether gamma-ray bursts might be a source of concern for us.

      Speaker: Prof. Cristiano Guidorzi (UniFe )
    • 2
      Silk/magnetic nanostructures hybrid materials: applications in flexible elctronics and nanomedicine. nature inspires technology

      Hybrid materials, combining inorganic and organic components, are the subject of an intense research activity, in particular for their technological potential. They display novel properties (e.g. mechanical, magnetic, or bioactive), which stem from the synergy between their constituent phases. In this intriguing research field, an original group of hybrid materials is represented by those made of magnetic nanostructures interfaced/mixed with bio-inspired matrices. In this contribution, two different hybrid systems are presented and discussed.
      They are based on silk, a natural biopolymer made of protein (i.e. fibroin) fibers highly biocompatible, elastic and tougher than steel.
      The first material was prepared for the field of flexible electronics, it was obtained from spider silk threads, and our analysis show that it represents a prototype with potential applications in the field of soft robotics. The second hybrid system was based on silkworm silk and was intended for the field of regenerative medicine. Our results prove that it can be used for biomedical applications, for instance as bio-active coating of orthopedic implants.

      Speaker: Dr Federico Spizzo (UniFe)
    • 3
      Stranger things ….. a new ``season’’ of stars?

      In 1984 Edward Witten, in a famous paper, formulated the hypothesis that the absolute ground state of matter is not 56Fe, but a cluster of up, down and strange quarks, an idea which became known as the “strange quark matter hypothesis”. In that seminal paper he also speculated that strange quark matter can constitute dark matter and that it can exist in chunks of all sizes, from small ones containing maybe just a few hundred quarks up to objects having the mass of the Sun and called strange quark stars.

      After almost 40 years we are still investigating Witten’s hypothesis, which, if true, would have consequences in nuclear physics, in astrophysics, in cosmology and, potentially, could even open a new path to producing energy.

      I will clarify what Witten’s hypothesis is and how it relates to a variety of observables, ranging from properties of compact stars, to features of explosive astrophysical processes, to properties of dark matter and I will discuss how strange quark matter can be searched for.

      In the last years a few observations have suggested that some specific objects can be identified as strange quark stars. In particular, one of the two objects in the merger GW190814 has a mass too large to be an ordinary neutron star [1,2], while the masses of SAX1808.4-3658 [3] and of HESS J1731-347 [4] are too small. We have shown instead that all of those objects can easily be interpreted as strange quark stars [5,6,7].

      [1] Abbott et al. ApJ 896:L44 (2020)
      [2] F. J. Fattoyev et al., Phys. Rev. C 102, 065805
      [3] T. Di Salvo et al., MNRAS 483, 767–779 (2019)
      [4] G.Pühlhofer & A. Santangelo, Nature Astronomy
      [5] I. Bombaci, A. Drago, D. Logoteta, G. Pagliara and I. Vidaña, PRL 126, 162702 (2021)
      [6] F. Di Clemente, A. Drago, P. Char, G. Pagliara, 2207.08704
      [7] F. Di Clemente, A. Drago, G. Pagliara, 2211.07485

      Speaker: Prof. Alessandro Drago (UniFe & INFN Ferrara)
    • 4
      Seeing Through Matter: innovation in biomedical imaging through X-rays energy and phase

      On November 8th, 1895, W. C. Roentgen serendipitously discovered X-rays, which have since become a fundamental tool for investigating the inner structure of matter in a non-destructive way. While significant progress has been made in the engineering of radiographic systems, the basic operating principles have remained unchanged to this day. In recent years, technological advancements in photon detection and radiation production have paved the way for innovative techniques beyond conventional radiography, such as spectral and phase-sensitive X-ray imaging. These techniques provide a more detailed and accurate evaluation of the composition and structure of the materials, aiming to achieve a better diagnostic power or reduce the radiation dose.
      This seminar will explore the evolution and applications of X-ray technology, reviewing recent research by our medical physics group, to address present challenges and future perspectives in biomedical X-ray imaging.

      Speaker: Dr Paolo Cardarelli (INFN Sezione di Ferrara)
    • 5
      Lithium ion batteries: the latest results on the germanium anodes developed by UNIFE

      Energy storage systems have undergone a true revolution since the beginning of the 90s thanks to lithium ion batteries, enabling the technology breakthrough that led to smartphones, laptops and, most recently to the electric mobility. However, the current challenges cannot be met by the traditional storage technology, and new materials are required that could be capable of storing more charge and energy per unit of mass of the battery system. In this context, the photovoltaic laboratory of the University of Ferrara is developing a new anodic material, based on germanium, to push forward the limits of this storage system.
      The electrodes are fabricated thanks to a two-step process: firstly, a thin germanium layer is realized by means of a chemical vapor deposition assisted by a plasma. This thin layer can’t be directly used as anodic material, due a huge volumetric variation during lithium exchange in the battery. For this reason, a nano-structuration step is performed to remove part of the germanium film by means of electrochemical etching with hydrofluoric acid. The resulting electrodes revealed a capacity over three times higher than standard graphite and an impressive stability over cycling, throughout hundreds of cycles. This presentation will give an overview of the fabrication process, and of the most recent and interesting results.

      Speaker: Donato Vincenzi (UniFe)
    • 6
      Quantum Computing, or: How I learned to Stop Worrying and Love the Qubit

      The technology to build computing devices using quantum-mechanical effects has seen a tremendous acceleration in the past few years. The advantage of quantum computers over classical devices lies in the possibility of using quantum superposition and entanglement of qubits to perform exponentially growing computations in parallel. This effect makes it possible to reduce the computational complexity of certain classes of problems, such as optimisation, sampling, combinatorial or factorisation problems.
      Research in High-Energy Physics is becoming more and more constrained by computing resources. Increasing dataset sizes and complexity call for a change of paradigm that could be met by quantum computation. Quantum algorithms have been proposed that require large scale fault-tolerant quantum computers. In contrast, today, we have access to the Noisy Intermediate-Scale Quantum (NISQ) hardware dominated by short coherence time (noise), a small number of qubits (from a few tens up to few thousands, in the case of quantum annealers) and limited connectivity.
      These limitations led to numerous investigations towards the design and optimisation of NISQ algorithms to demonstrate their viability and a possible quantum advantage over the current hardware.
      Some examples of potentially promising HEP applications are given.

      Speaker: Concezio Bozzi (Istituto Nazionale di Fisica Nucleare)
    • 7
      HPC for Computational Physics

      High Performance Computing (HPC) systems, as the name explains, are what computer
      technology is capable of building more powerful than conventional computers.
      For over 50 years, their extreme capabilities have led to considerable progress in academic and industry research, enabling numerical simulations to model several
      physical phenomena at any scale, and making it possible to understand
      their behavior and predict the evolution.
      Digital simulations, together with the newest paradigms of artificial intelligence, are going to be more and more at the base of any technological innovation, but also of social progress, making improvements in crucial fields such as health,
      food, energy transition and monitoring of climate changes.
      These "Formula 1" computers allow researchers trained to use their exceptional
      computational capabilities to achieve otherwise unachievable results.
      In this talk we discuss the architecture of most recent HPC systems, and the issues to
      unleash their computational power, and some results.

      Speaker: Sebastiano Fabio Schifano (Department of Environmental and Prevention Sciences Ferrara University and INFN)
    • 8
      The Strong Crystalline Field: or how to play with particle beams using tiny crystals!

      Exploring the interaction between particles and crystalline structures offers intriguing insights at the intersection of particle and solid state physics, with significant applications.

      Crystals present a distinctively simple environment for the investigation of strong electromagnetic fields. When energetic particles interact with crystals near their major crystallographic directions, the crystal lattice's coherence can induce extremely strong electric fields in the particle's rest frame, potentially surpassing the so-called Schwinger field or quantum critical field.

      This Strong Crystalline Field yields a host of applications for particle accelerators, ranging from generating intense radiation sources and steering particle beams. These applications extend across a broad spectrum of fields, including particle physics at major facilities like the CERN and Fermilab, as well as material science and nuclear medicine.

      Moreover, Strong Crystalline Fields are integral to the advancement of innovative ultra-compact detectors, specifically tailored for the precise detection of high-energy gamma rays. These new detectors find application in accelerator and satellite experiments, mainly for research into physics Beyond the Standard Model and the indirect detection of Dark Matter.

      Speaker: LAURA BANDIERA (Istituto Nazionale di Fisica Nucleare)
    • 9
      The left hand of lightness: how we get to understand neutrinos (and other particles) by hunting for the most ancient light in the Universe

      Neutrinos are copiously produced in the early stages of the Universe history. They are the second most abundant species after cosmic photons to been wandering through the cosmic web for billions of years. They are also the most puzzling particles within the standard model of particle physics. Many of their properties - and the physical origin of these properties - are still mysterious. We have never measured their total mass (but we know for sure they have mass), we cannot explain where it comes from, we do not know whether neutrinos are their own antiparticles. However, we do know that neutrinos played - and still play - an important role in shaping the Universe as we observe it today.
      In this colloquium, we will discover how the observation of the cosmic microwave background (CMB) - the relic radiation from the Big Bang - can unveil the mysteries of neutrinos. On top of this, throughout its long history, the Universe may have seen the birth of new relic particles still to be discovered, or even the manifestation of exotic properties of known particles still to be detected. We will learn how cosmology promises to open the window to the beyond-the-standard-model landscape that physicists have been longing for.

      Speaker: Martina Gerbino (Istituto Nazionale di Fisica Nucleare)