Ciclo di Conferenze dei corsi di Laurea in Fisica del Dipartimento di Matematica e Fisica
Edizione 2019
Andrea Marinucci
Dipartimento di Matematica e Fisica, Università Roma Tre
Not so close to the event horizon: latest results on circumnuclear matter in supermassive black holes
Link identifier #identifier__72422-1Locandina – 15 gennaio 2021, ore 15:00 Aula B
The circumnuclear medium of Active Galactic Nuclei (AGN) is a very complex environment, where several physical components (a corona of hot electrons, an accretion disk, a dusty ”torus”) are responsible of much of the observed properties in the X-rays. These regions extend from very close to the event horizon up to thousands of gravitational radii from the central supermassive black hole. I will review the observational progresses on some of the physical parameters of such structures obtained using NASA and ESA observatories (NuSTAR, Chandra and XMM-Newton) and discuss future prospects for constraining their geometries, in view of the launch in 2021 of the Imaging X-ray Polarimetry Explorer (IXPE).
Salvatore Capozziello
Department of Physics “Ettore Pancini” – University of Naples Federico II
Beyond Einstein: Dark Energy and Dark Matter as Curvature Effects
Link identifier #identifier__71345-2Locandina – 5 febbraio 2019, ore 15:00 Aula B
Extended Theories of Gravity have recently attracted a lot of interest as alternative candidates to explain the observed cosmic acceleration, the flatness of the rotation curves of spiral galaxies, the gravitational potential owhatf galaxy clusters, and other relevant astrophysical phenomena. Very likely, we call “dark matter” and “dark energy” are nothing else but signals of the breakdown of General Relativity at large scales and could be interpreted as a sort of “curvature effect”.
Furthermore, PPN-parameters deduced from Solar System experiments and strong field astrophysical phenomena (black holes, neutron stars, gravitational waves) do not exclude the possibility that such theories could give other observable effects. We review these results giving the basic ingredients of such an approach.
Alessandro Vichi
Institute of Physics, Ecole Polytechnique
Fédérale de Lausanne (EPFL)
The conformal bootstrap: strong dynamics under siege
Link identifier #identifier__142588-3Locandina – 5 marzo 2019, ore 15:00 Aula B
Originally formulated in the 70’s, the conformal bootstrap is the ambitious idea that one can use internal consistency conditions to carve out, and eventually solve, the space of conformal field theories. In this talk I will review recent developments in the field which boosted this program to a new level and led, for instance, to the most precise determination of the 3D Ising critical exponents.
I will describe how the bootstrap lets us address questions across theoretical physics, from boiling water to quantum gravity.
Philipp Roloff
CERN
Electron-positron collisions at the Compact Linear Collider
Link identifier #identifier__193432-4Locandina – 2 aprile 2019, ore 15:00 Aula B
An electron-positron collider is widely considered to be the next large international project in high-energy particle physics. An overview of proposed linear and circular collider options is given. The Compact Linear Collider (CLIC) is a mature option for a future electron-positron collider operating at centre-of-mass energies up to 3 TeV. Highlights from the R&D programs for the CLIC accelerator and detector are shown. The CLIC physics potential is best exploited in a staged construction and operation scenario. The first stage at 380 GeV is optimised for precision measurements of the Higgs boson and top quark. The higher energy stages, currently assumed to be at 1.5 and 3 TeV, significantly enhance the sensitivity to many new physics scenarios.
Angela Di Virgilio
INFN-Pisa
Ring Laser gyros, instruments to study the earth and the sky
Link identifier #identifier__83174-5Locandina – 7 maggio 2019, ore 15:00 Aula B
Ring Laser gyros are inertial sensors based on the Sagnac effect. They measure absolute angular rotation rates and at present are the most sensitive gyros for earth based apparatus. Sensitivity below prad/s has been already obtained.
As most of the very high sensitivity apparatus, they have a large range of applications: from the General Relativity test on Earth of the Lense-Thirring effect, to geodetic measurements, as polar motion, chandler wobbler, tides in general, and to seismology studies.
We have proposed the GINGER experiment, an array of ring laser gyros for the Lense Thirring effect with 1% accuracy. The GINGER apparatus will be outlined.
As a preparatory phase to develop GINGER, we have built the large ring laser gyro GINGERINO inside the Gran Sasso Laboratory. At present on the world, GINGERINO is the most sensitive ring laser based on the so called hetero-lithic mechanical structure, and it is the only one operative inside an important seismically active region.
Lucio Calcagnile
Department of Mathematics and Physics “Ennio De Giorgi” – University of Salento
Accelerator Mass Spectrometry at CEDAD – The first 15 years
Link identifier #identifier__37939-6Locandina – 4 giugno 2019, ore 15:00 Aula B
CEDAD – CEnter of Applied Physics, DAting and Diagnostics – is a research Center at the University of Salento established 15 years ago in the framework of a Coordinated Plan between the University of Catania and Lecce. The main goal of the project was to realize the first Italian Center for research and service for radiocarbon dating by Accelerator Mass Spectrometry (AMS). Over the years at CEDAD the 3 MV Tandetron accelerator has been continuously upgraded so that six beamlines and four ion sources have been designed and connected to the accelerator. CEDAD is nowadays a multidisciplinary facility for environmental, archaeological, geological and materials science studies with nuclear techniques such as AMS, RBS/Channeling, PIXEPIGE, Ion Implantation, and Nuclear microbeam.
Recently a new AMS beamline for rare isotopes other than 14C has been designed in collaboration with the Ion Beam Physics group at ETH in Zurich for the detection of rare isotopes such as 10Be, 26Al, 129I and uranium isotopes. In addition a new gas ion source for measuring 14C samples with masses less than 10 μg has been installed. The research activities will be mainly in the fields of Earth, Marine sciences and nuclear safeguards. In this seminar a brief history of the CEDAD and the AMS technique will be presented and the SIDART, BLU-ARCHEOSYS, IT@CHA, DICET and BOLAS projects will be described. It will be shown the potentialities of the integrated approach of the IBA and AMS techniques for performing with the same accelerator studies in many research fields. Moreover in the field of environmental monitoring an overview will be presented of research carried at CEDAD for monitoring the anthropogenic carbon dioxide emissions into the atmosphere and for the quantification of the biogenic fraction in carbon based products (plastics, resins, bio-fuels) and in industrial atmospheric emission such as flue gas from WTE (Waste to Energy Plants).
Pietro Gambardella
Department of Materials, ETH Zurich, CH – 8093 Zürich, Switzerland
The new spintronics:switching, sensing, and coupling nanomagnets enabled by the spin-orbit interaction
Link identifier #identifier__40565-7Locandina – 2 luglio 2019, ore 15:00 Aula B
The spintronics landscape has changed dramatically over the last ten years. Much of this change is due to a deeper understanding of the interactions and charge-spin conversion processes mediated by spin-orbit coupling in different classes of materials. In this talk, I will discuss new opportunities to sense and manipulate the magnetization of metallic and insulating nanomagnets. Illustrative examples will focus on unusual magnetoresistance effects [1-3], ultrafast switching of magnetic dots and tunnel junctions [4-7], as well as chirally coupled spin lattices, synthetic skyrmions, and antiferromagnets [8].
[1] C.O. Avci, J. Mendil, G.S.D. Beach, and P. Gambardella, Phys. Rev. Lett. 121, 087207 (2018). [2] C.O. Avci et al., Appl. Phys. Lett. 110, 203506 (2017). [3] C.O. Avci et al., Nat. Phys. 11, 570 (2015). [4] A. Manchon et al., Rev. Mod. Phys. (in press, arXiv:1801.09636). [5] M. Cubukcu et al., IEEE Trans. Magn. 54, 9300204 (2018). [6] M. Baumgartner et al., Nat. Nanotech 12, 980 (2017). [7] M. Miron et al., Nature 476, 189 (2011). [8] Z. Luo et al., Science 363, 1435 (2019).
Giorgio Arcadi
Dipartimento di Matematica e Fisica Università Roma Tre & INFN Sezione di Roma Tre
Particle Dark Matter: Theory and Detection
Link identifier #identifier__38675-8Locandina – 1 ottobre 2019, ore 15:00 Aula B
A large fraction of the High Energy community agrees on the conjecture that the Dark Matter Puzzle is solved through the existence of new particle states cosmologically stable and with suppressed interactions with ordinary matter.
I will give an overview of some popular DM candidates illustrating their production mechanism in the Early Universe and the showing the capability of current and next future experiments of probing particle Dark Matter theories.
Paolo Lenisa
Università di Ferrara and INFN
Search for the electric dipole moment of charged particles in storage ring
Link identifier #identifier__93352-9Locandina – 5 novembre 2019, ore 15:00 Aula B
The Electric Dipole Moment (EDM) of elementary particles, including hadrons, is considered as one of the most powerful tools to study CP-violation beyond the Standard Model. Such CP-violating mechanisms are searched for to explain the dominance of matter over anti-matter in our universe.
Up to now EDM experiments concentrated on neutral systems, namely neutron, atoms and molecules. Storage rings offer the possibility to measure EDMs of charged particles by observing the infuence of the EDM on the spin motion.
A step-wise approach to the measurement of the proton EDM, starting with a proof-of-principle experiment at the existing storage ring Cooler Synchrotron COSY at Forschungszentrum Jülich, followed by an electrostatic prototype ring allowing for a simultaneous operation of counter circulating beams in order to cancel systematic effects, to the design of a dedicated 500 m circumference storage ring will be presented
Luciano Burderi
University of Cagliari
GrailQuest & HERMES: Hunting for Gravitational Wave Electromagnetic Counterparts and Probing Space-Time Quantum Foam
Link identifier #identifier__35782-10Locandina – 3 dicembre 2019, ore 15:00 Aula B
GrailQuest (Gamma-ray Astronomy International Laboratory for Quantum Exploration of Space-Time) is an ambitious astrophysical mission concept that uses a fleet of small satellites, whose scientific objectives are discussed below. Within Quantum Gravity theories, different models for space-time quantisation predict an energy dependent speed for photons. Although the predicted discrepancies are minuscule, Gamma-Ray Bursts, occurring at cosmological distances, could be used to detect this signature of space-time granularity with a new concept of modular observatory of huge overall collecting area consisting in a fleet of small satellites in low orbits, with sub-microsecond time resolution and wide energy band (keV-MeV). The enormous number of collected photons will allow to effectively search these energy dependent delays. Moreover, GrailQuest will allow to perform temporal triangulation of high signal-to-noise impulsive events with arc-second positional accuracies: an extraordinary sensitive X-ray/Gamma all-sky monitor crucial for hunting the elusive electromagnetic counterparts of Gravitational Waves. A pathfinder of GrailQuest is already under development through the HERMES (High Energy Rapid Modular Ensemble of Satellites) project: a fleet of six 3U cube-sats, each hosting a 64 square cm area detector, to be launched by the end of 2021. In this context, the fleets of hundreds/thousands satellites in Low Earth Orbits, designed or under construction to provide Internet access from anywhere on Earth (e.g. Starlink or OneWeb) offer an unique opportunity to perform this experiment by placing the detectors as piggybacks on each satellite of the constellation. Within the payload constraints indicated to fit the Airbus-OneWeb small-sat platform capabilities, we propose to accomodate an upgraded version (few thousands of cm2 effective area) of the detectors designed for the HERMES project in order to reach an overall collecting area of few tens of square metres, sufficient to accomplish the compelling objectives described above.