Giorgio Parisi, Nobel Prize and Beyond
"Parisi is right" says the Italian Prime Minister Mario Draghi "our research funding is way lower than that of the countries around us and the government is determined to bridge this gap as much as possible, both for basic research funds and for funds toward applied research "
On October 5th 2021, the Swedish Royal Academy of Sciences announced that Giorgio Parisi is one of the Nobel Prize winners in physics. Parisi is a theoretical physicist who has been trained, has worked and works in Rome, and for the past three years he has been the President of the Accademia Nazionale dei Lincei. After a crescendo of prestigious awards, including the Boltzmann Medal and the Wolf Prize, he received the Nobel "for the discovery of the interplay of disorder and fluctuations in physical systems from atomic to planetary scales".For most of the best physicists in the world, for many international colleagues, for his collaborators and for the students of the Sapienza University who have attended his courses, Giorgio is a scientist of supreme level, one of those sitting at that imaginary table with the giants of the history of physics, from the Hellenistic period to the present day.
But what do physicists really do? Theorists have a fascinating job: they describe the world by grasping its essence and do it so well that with their methods one can often make accurate predictions or, some other times, one can understand why predictions are partial or impossible. From those methods derives our ability to build prodigious machines like those that drove the industrial revolution with all its branches and those that will drive the next ones. To do this, physicists use, in the Galilean tradition, that extraordinary quantitative language which is mathematics. Of course the part of the world that can be described with physics is very limited but, trying and trying again, it gradually widens as the research progresses.
This year the Nobel was awarded for the understanding of complex physical systems and, in the case of Parisi, mostly for his statistical physics theory that links disorder and fluctuations. To describe it in a colloquial way, one can draw inspiration from the same effective metaphor used in the introduction of the text by Mézard, Parisi and Virasoro: consider a system composed by many particles - imagine them as a group of people. If each of their interactions is cooperative, the system will soon find a shared agreement and the consensus reached will be certain and satisfactory for everyone. If, on the other hand, the interactions are disordered, some cooperative and others competitive, an agreement will not be found that satisfies everyone and the best compromises will be very difficult to reach. In this second case, the agreement obtained will be intrinsically fluctuating. Moreover, from the nature of those fluctuations Parisi's theory is able to obtain the main properties of those systems.
When Parisi approached these themes in the late 1970s, they were not fashionable and had no relevant practical applications. Their understanding, as the American physicist who proposed them to the community (PW Anderson, Nobel Prize for Physics in 1977) said, deserved nevertheless a thorough study for the simple fact that they represented an authentic scientific mystery.
The Nobel Prize to Parisi was therefore awarded for a theoretical result that anticipated many of the subsequent experiments, a freely invented theory as Einstein liked to say, one that the pen deposits on the white paper, and which, over time, becomes essential to understand a whole series of real phenomena. There was, however, a somehow experimental side that accompanied his work, provided by the virtual environment of computer simulations. Using his legendary familiarity with the computer as early as in the 80s, when most considered it a hellish contraption, Giorgio has always compared his theory with the data produced by the machine in a sort of meta-experiment, receiving feedback and confirmation.
More than forty years after its discovery, the conceptual scheme underlying that theory, and developed through the very rich collaborations that the author has had, has become a new paradigm of science. It represents an interpretative method with applications to the behavior of glassy materials and that of random lasers, to name just a couple. But not only that, an uncommon fact for a theory born in the bed of theoretical physics, is that the same scheme has fertilised fields distant from the hard sciences and opened new horizons such as biological systems - for the immune system, for mechanisms describing the associative memory in the brain- and ecological, economic, financial systems etc. Finally, the neural networks, which led to those marvels of modern artificial intelligence based on machine learning, are studied with ideas, methods and techniques of Parisi's theory.
But how does a Nobel winner come out? Is it a matter of nature or nurture ? A set of innate natural gifts or the intellectual environment in which he grew up? Certainly it is an artfully mixed combination of the two, according to a very secret recipe. Giorgio's natural intuition, his analytical skills and his curiosity found themselves immersed in that school of Italian physics founded by Enrico Fermi, that Amaldi had gathered in Rome after WWII. Among his mentors, first and foremost the physicist Cabibbo, among his colleagues Altarelli, Maiani, Jona Lasinio and Francesco Guerra. To the latter we owe some of the best ideas that led to the slow metamorphosis, still in progress, of that brilliant theory of Parisi into a mathematically rigorous construct deducible from the principles of thermodynamics, a transformation that allowed mathematicians to approach the study of disordered systems. The scientific environment in Rome, in Giorgio's time, has become the country's school of excellence, the one that attracts at the same time the best students, the best researchers and the best international visitors. In fact, a remarkable and counter-trend phenomenon manifests itself at conferences on disordered systems: during discussions in small groups or coffee breaks, whether they take place in Paris, in Kyoto or in New York, many non-natives speak Italian with Italians and not infrequently among themselves as they did in Rome at Giorgio's school.
And how does the assignment of a prestigious award come about? Science is not measured in inches like heights. In a group you can always line up people and choose the highest one but talent is an infinitely richer quality.Its evaluation is essentially based on the impact of the scientific contribution but since science is also power and wealth for the host country it is natural that political as well as personal factors play a role.It is natural I say, but it is not obvious. Certainly some countries in the world are well aware of this and when it is necessary to present their candidate for a prestigious international award they silence internal tensions, choose their champion, and express themselves unanimously. A deserving scientist working in those countries where science has the consideration it deserves will have his honest chance of receiving the awards he can aspire to. But Italy does not always have the awareness of being a country, it is too busy chasing the financial bills as if they were balloons rolling down the stairs, staging and enjoying talk shows where influencers, extras and improvised politicians discuss everything and more, especially in the fields of competence of others. And so it happens that the Italians who receive awards work more often abroad after being trained in Italy, assisted by an organization that we are no longer able to express after having invented it during the Roman Empire.
A Nobel Prize that reaches an Italian who works in Italy is therefore a different phenomenon, which has followed a different path. The Nobel Prize to Parisi was a natural and unstoppable process of accumulating scientific credit, aided by the collaborations and admiration that surrounded him. The Italian scientific environment together with the international one spontaneously united around this extraordinary scientist with a kind character, alien to conflicts and generous in sharing his ideas and accompanied him to the podium. It goes without saying, as Giorgio himself often complains, that many Italian researchers have not received the recognition they deserved.
Parisi has always been concerned about the health of science in Italy, its dramatic needs, first of all the lack of investment. It is neither a mystery nor a surprise that his appeals have been systematically ignored despite promises made by politics. Prime Minister Draghi’s words and tones are therefore welcomed, perhaps it is the right time to make a change by taking the opportunity of the The National Recovery and Resilience Plan. Parisi, however, accepted with great caution the optimism of the minister of university and research on the evening of the celebrations in the great hall of the Sapienza University.
Five years ago he summarized his appeals as follows: "In a world dominated by the knowledge economy, a country that does not invest in research, development and culture has no future". Now that this has become the appeal of a Nobel prize winner, who knows if it will be enough to convince the government that a future would be useful.
