The top-quark mass: interpretation of the measurements and theoretical uncertainties

The top-quark mass is a fundamental parameter of the Standard Model, which, together with the mass of the W boson, constrained the Higgs-boson mass even before its discovery. The talk will discuss the interpretation of the top-quark mass measurements at the LHC: in particular, the relation between the reconstructed mass, relying on analyses based on Monte Carlo event generators, and theoretical definitions, such as the pole mass, will be investigated. More generally, the sources of theoretical uncertainties will be reviewed, taking particular care about the impact of the hadronization of bottom quarks in top decays.

Friday, 12 February 2016, ore 14:30 — Sala Wataghin

The "Human Brain Project": the INFN contribution

Novel experimental techniques enable the quantitative exploration of the system architecture of the Brain. Large-scale simulations are moving to the status of predictive models of the Brain behavior. Indeed, Computational Neuroscience is an emerging quantitative discipline: it brings together experimental results, numerical simulations and theoretical models of the Brain, at different levels of abstraction. The translational challenge is to improve the therapies of brain diseases and trauma. In Europe the yearly cost of brain disorders and trauma is estimated at 798 billion/year (increasing, due to population aging). Therefore, the EU Commission launched the Human Brain Project (HBP) flagship project funded with approximately 90M/year until 2023. INFN will enter the HBP project in April 2016, leading the WaveScalES team. We will observe the cortical slow wave activity and the cortical response to localized impulses and we will attempt to match experimental observation with large scale simulationsof cortical activity.

Friday, 29 January 2016, ore 14:30 — Aula Magna

Learning from the Big-Bang about the litte-bangs and viceversa

While the physics underlying cosmology and heavy-ion collisions is very different, of course, the theoretical challenges for understanding the dynamics of both systems show remarkable commonalities. In this colloquium, I explain on the one hand how the modern description of the expansion dynamics of heavy-ion collisions parallels developments in cosmology. On the other hand, I discuss examples for how concepts widely used in heavy-ion phenomenology may be employed to shed light on two central topics in cosmology, namely large-scale structure formation and the nature of dark matter.

Thursday, 15 January 2016, ore 14:30 — Aula Magna

The decay-law in Quantum Mechanics and Quantum Field Theory

The exponential decay law of quantum unstable particles is not exact: deviations at short and long times occur. We review the theoretical origin of these deviations as well as their experimental verification. A related concept is the quantum Zeno effect, i.e. the increase of the lifetime due to frequent observations. This peculiar quantum phenomenon has been also confirmed experimentally. Then, we study the theory of the decay law for a moving unstable particle and show some unexpected features of the latter.

Friday, 11 December 2015, ore 14:30 — Aula Magna

100 years of General Relativity

General Relativity is at the same time a concrete and so far verified Physical Theory and a Philosophical Paradigm that has deeply influenced the whole development of Fundamental Science in the XX century. The conceptual history of GR is reviewed from its roots in XIX century Mathematics up to the present. Its exceptional relevance in directing Physical Thinking of the XX century and in framing Cosmology, Astrophysics and the theoretical quest for the Fundamental Laws of Nature is emphasized. Black Holes constitute one of the most striking implications of GR that are observed in Astrophysics and provide deep connections with Quantum Physics, current development of Unified Theories and Philosophy. Gravitational waves, the intrinsic most fundamental prediction of GR, have not yet been directly detected, but their existence is indirectly verified through the slowing down of rotation periods in binary systems of compact stars. G-wave Astronomy is expected to be born very soon, with the help of upgraded interferometers. It will provide an entire new picture of the Universe, giving GR an even stronger place in the Physical Research and Thought of the XXI century.

Wednesday, 9 December 2015, ore 15:30 — Aula Magna

The Dark Universe after Planck

The cosmic microwave background radiation allows us to test the evolution and content of the Universe. After an introduction, I will review the latest findings of the ESA Planck satellite on the 'dark' content of the universe and the possibility to test gravity and general relativity at cosmological scales.

Friday, 27 November 2015, ore 14:30 — Sala Wataghin

The temperature of the Quark-Gluon Plasma

The theory of strong interactions predicts that at high temperatures strongly interacting matter will form a new state of matter, a plasma of unbound quarks and gluons. During the first ten microseconds after the Big Bang, our universe consisted of such a plasma, and present experiments at CERN and Brookhaven attempt to recreate this primordial state in the laboratory. I discuss how such studies can be carried out and consider in particular how the temperature of the plasma can be measured.

Friday, 20 November 2015, ore 14:30 — Aula Magna

Dall'infinitamente piccolo all'infinitamente grande

Due grandi rivoluzioni (incompiute) si sono prodotte nella fisica del 900: da un lato la Meccanica Quantistica che presiede ai fenomeni del mondo submicroscopico e dall'altra la Relatività Generale che governa i fenomeni cosmici. Ci sfugge per ora la compatibilità di queste due teorie che, si ritiene, ci permetterà di capire la maggior parte dei fenomeni che tuttora permangono misteriose come energia del vuoto, materia oscura ecc.

Friday, 30 October 2015, ore 14:30 — Aula D

Poincaré symmetry and thermal field theories

The analytic continuation to an imaginary velocity of the canonical partition function of a thermal system expressed in a moving frame has a natural implementation in the Euclidean path-integral formulation in terms of shifted boundary conditions. The Poincare' invariance underlying a relativistic theory implies a dependence of the free-energy on the compact length L0 and the shift xi only through the combination beta=L0(1+xi^2)^(1/2). This in turn implies a set of Ward identities among the correlators of the energy-momentum tensor which have also interesting applications in lattice field theory. In particular, they offer identities to renormalize non-perturbatively the energy-momentum tensor and novel ways to compute thermodynamic potentials. I will present numerical results for the renormalization constants of the traceless components of the energy-momentum tensor obtained with a precision of roughly half a percent for values of the bare coupling constant in the range 0<=g^2<=1. Results for the equation of state of the SU(3) Yang-Mills theory obtained by implementing these ideas will be also discussed.

Friday, 23 October 2015, ore 14:30 — Aula Magna

Translating evolution into technology: from artificial antibodies to humanoids

    Humano-centric technologies (impacting on health care, welfare, disaster recovery, sustainable materials, life expectancy etc..) are being developed along a pathway inspired by evolution. The natural development of intelligent and optimized living systems, from molecular level to mammalians, is imitated by a blend of nanotechnology, life science, cognition and engineering which results in a number of bio-inspired technologies. A few representative examples will be discussed, including:
  • Artificial antibodies for intelligent drug delivery and ultra-high sensitive diagnostics - Smart materials based on natural fibers
  • Robotic plants (plantoids)
  • Robotic animals (animaloids)
  • Humanoids.
    • Several applications of those technologies will be briefly addressed during the presentation.

Friday, 9 October 2015, ore 14:30 — Aula A