Giorgio Parisi (born 4 August 1948) is an Italian theoretical physicist, whose research has focused on quantum field theory, statistical mechanics and complex systems. His best known contributions are the QCD evolution equations for parton densities, obtained with Guido Altarelli, known as the Altarelli–Parisi or DGLAP equations, the exact solution of the Sherrington–Kirkpatrick model of spin glasses, the Kardar–Parisi–Zhang equation describing dynamic scaling of growing interfaces, and the study of whirling flocks of birds. He was awarded the 2021 Nobel Prize in Physics jointly with Klaus Hasselmann and Syukuro Manabe for groundbreaking contributions to theory of complex systems, in particular "for the discovery of the interplay of disorder and fluctuations in physical systems from atomic to planetary scales".

Early life and education

Giorgio Parisi received his degree from the University of Rome La Sapienza in 1970 under the supervision of Nicola Cabibbo.

Career

He was a researcher at the Laboratori Nazionali di Frascati (1971–1981) and a visiting scientist at the Columbia University (1973–1974), Institut des Hautes Études Scientifiques (1976–1977), and École Normale Supérieure (1977–1978). From 1981 until 1992 he was a full professor of Theoretical Physics at the University of Rome Tor Vergata and he is now professor of Quantum Theories at the Sapienza University of Rome. He is a member of the Simons Collaboration "Cracking the Glass Problem". From 2018 until 2021 he was the president of the Accademia dei Lincei and in 2023 he was elected Fellow of The World Academy of Sciences.

Research

Parisi's research interests are broad and cover statistical physics, field theory, dynamical systems, mathematical physics and condensed matter physics, where he is particularly known for his work on spin glasses and related statistical mechanics models originating in optimization theory and biology. In particular, he made significant contributions in terms of systematic applications of the replica method to disordered systems, even though the replica method itself was originally discovered in 1971 by Sir Sam Edwards. He has also contributed to the field of elementary particle physics, in particular to quantum chromodynamics and string theory. Together with Guido Altarelli, he introduced the so-called Dokshitzer–Gribov–Lipatov–Altarelli–Parisi equations. In the field of fluid dynamics he is known for having introduced, together with Uriel Frisch, multifractal models to describe the phenomenon of intermittency in turbulent flows. He is also known for the Kardar–Parisi–Zhang equation modelling stochastic aggregation. From the point of view of complex systems, he worked on the collective motion of animals (such as swarms and flocks). He also introduced, together with other Italian physicists, the concept of stochastic resonance in the study of climate change.

Honors and awards

Giorgio Parisi is a foreign member of the French Academy of Sciences, the American Philosophical Society, and the United States National Academy of Sciences.

Activism

Since 2016, Giorgio Parisi has been leading the movement "Salviamo la Ricerca Italiana" to put pressure on the Italian and European governments to start funding basic research above the subsistence level.

Selected publications