Laudatio
On the occasion of the Sigillum Magnum to Giorgio Parisi
Good evening, first of all thanks to the Magnificent Rector.
Thanks to all present: Authorities, Colleagues, Students, Ladies and Gentlemen.
Last year Giorgio Parisi received the Nobel Prize in Physics which was assigned to him "for the discovery of the relationship between disorder and fluctuations in physical systems from the scale of atoms to that of planets".
Parisi, even regardless of the Nobel, is a public figure of high stature and in this brief introduction I will try to outline a profile, far from being complete. I will build on my experience with him that begins when I was a student at University La Sapienza in Rome and continues with the collaborations and scientific interactions we have had.
Parisi is a theoretical physicist. He studied, worked and still works in Rome, was President of the Accademia dei Lincei and is now its Vice President. The Nobel came after a crescendo of prestigious awards, including the Boltzmann Medal and the Wolf Prize.
A theoretical physicist, incidentally, does a fascinating job: he is attentive to experimental results but moves guided by curiosity, follows principles of simplicity, logical coherence and uses that masterful language that is mathematics.
But who is really Giorgio Parisi? For many of the best physicists in the world and among his international colleagues, for his collaborators (over 300) and for the university students who have followed his courses, Giorgio is a scientist of the highest level, one of those who sits at that imaginary table with the giants of the history of physics.
In his long career as a scholar, Parisi has managed to do what very few physicists can do: he anticipated nature, he freely invented a physical theory, to use expressions dear to Einstein. At the end of the 70s the problem he was studying was neither fashionable nor showed relevant practical applications, but as another Nobel Prize winner for Physics, Philip Anderson, commented, it deserved to be studied because it represented a truly interesting mystery.
In short, Parisi laid the foundations for a new scientific theory, that of complex systems . To describe it in a colloquial way we use the effective metaphor of the introduction of his book with Mézard and Virasoro : let's think of a group of people arguing among themselves. If each of their interactions is cooperative, the group will surely and quickly find a shared agreement. The consensus reached will be satisfactory for all. If instead the interactions are disordered, some cooperative and some competitive, it will be impossible to find an agreement that satisfies all and the best compromises will be very difficult to reach. Trying again the results will be different test after test. But those compromises are not entirely random, among them Parisi has identified an admirable structure that keeps surprising us, a hierarchy with tree branches... and it would be nice to continue but here the metaphor stops, because to be more precise words are not enough but the blackboard is needed and that mathematical language we were talking about.
More than forty years have passed since its discovery and the conceptual framework underlying that theory has become a new paradigm of science. It represents an interpretative method for many phenomena, from the behavior of glassy materials to that of random lasers.
Furthermore, a very rare fact for a theory born in the field of theoretical physics, that same scheme has fertilized fields far from the hard sciences and opened new research horizons in biology, ecology, economics and finance.
Finally, artificial neural networks, which led to those marvels of modern artificial intelligence based on machine learning, are studied with the ideas, methods and techniques of Parisi's theory.
But how do you get to a Nobel? The question arises from two points of view, that of the individual and that of the prize.
Does the set of innate natural talents or the intellectual environment in which he grew up count for the individual? Certainly both things, artfully mixed according to a very secret recipe. In Giorgio's case, his natural intuition, his analytical skills and his curiosity found themselves immersed in that Italian school of physics that Amaldi had rebuilt after the war in Rome with Fermi's legacy. Among his masters, first of all the physicist Cabibbo, among his colleagues Altarelli, Maiani, Jona-Lasinio and Guerra.
And how does the assignment of such a prestigious award come about? Science is not measured in centimeters like heights. In a group you can always line up people and pick the tallest one but talent is an infinitely richer quality. In evaluating it, one is certainly based on the scientific contribution. But since science is also power and wealth for the country that hosts it, it is natural that factors such as political as well as personal factors intervene. Some countries in the world are well aware of this and when they have to present their candidate for an international prize, they silence internal tensions, choose their champion, and speak as one.
But ours is not one of those countries and a Nobel prize awarded to an Italian who works in Italy is a phenomenon that has followed a different process.
The Nobel to Parisi was a natural and unstoppable process of accumulation of scientific credit. This extraordinary scientist with a kind character, alien to conflicts and generous in sharing his ideas has unified the Italy of science! The international scientific environment together with the national one spontaneously accompanied him to the podium.
For his human characteristics as much as for the scientific ones, Prof. Parisi also enjoys a well-deserved heritage of trust from individuals and institutions. In fact, he has always dealt with the health of science in Italy, collaborating with the country's governments, pointing out our dramatic lack of investment in research which is still below the European average.
Finally, his commitment during the pandemic, in disseminating correct scientific information, in requesting data on infections, his role in international scientific diplomacy, all of this places him in a central position in our society .
I won't keep you any longer.
Today, in the oldest university in the world... the most recent and youngest Italian Nobel Prize winner: Giorgio Parisi!
Pierluigi Contucci, 28 November 2022.
