Carlo Rovelli

Carlo Rovelli was born in Verona, Italy, on 3 May 1956. He attended the Liceo Classico Scipione Maffei in Verona. In the 1970s, he participated in the student political movements in Italian universities. He was involved with the free political radio stations Radio Alice in Bologna and Radio Anguana in Verona, which he helped found. In conjunction with his political activity, he was charged, but later released, for crimes of opinion related to the book Fatti Nostri, which he co-authored with Enrico Palandri, Maurizio Torrealta, and Claudio Piersanti.

Rovelli has credited his occasional use of LSD at this time with an influence on his later interest in theoretical physics, saying of his experience: "it was an extraordinarily strong experience that touched me also intellectually... Among the strange phenomena was the sense of time stopping. Things were happening in my mind but the clock was not going ahead; the flow of time was not passing any more... And I thought: ‘Well, it's a chemical that is changing things in my brain. But how do I know that the usual perception is right, and this is wrong? If these two ways of perceiving are so different, what does it mean that one is the correct one?"

In 1981, Rovelli graduated with a BS/MS in physics from the University of Bologna, and in 1986 he obtained his PhD at the University of Padova, Italy. Rovelli refused military service, which was compulsory in Italy at the time, and was therefore briefly detained in 1977. He held postdoctoral positions at the University of Rome, the International School for Advanced Studies in Trieste, and Yale University. Rovelli was on the faculty of the University of Pittsburgh from 1990 to 2000, where he was also affiliated with the Department of History and Philosophy of Science. Since 2000 he has been a professor at the Centre de Physique Théorique de Luminy of Aix-Marseille University in France.

In 1988, Rovelli, Lee Smolin and Abhay Ashtekar introduced a theory of quantum gravity called loop quantum gravity. In 1995, Rovelli and Smolin obtained a basis of states of quantum gravity, labelled by Penrose's spin networks, and using this basis they were able to show that the theory predicts that area and volume are quantized. This result indicates the existence of a discrete structure of space on a very small scale. In 1997, Rovelli and Michael Reisenberger introduced a "sum over surfaces" formulation of the theory, which has since evolved into the currently covariant "spin foam" version of loop quantum gravity. In 2008, in collaboration with Jonathan Engle and Roberto Pereira, he has introduced the spin foam vertex amplitude which is the basis of the current definition of the loop quantum gravity covariant dynamics. Loop theory is today considered a candidate for a quantum theory of gravity. It finds applications in quantum cosmology, spinfoam cosmology and quantum black hole physics.

In his 2004 book, Quantum Gravity, Rovelli developed a formulation of classical and quantum mechanics that does not make explicit reference to the notion of time. The first step towards a theory of quantum gravity without a time variable is described by Wheeler–DeWitt equation. The timeless formalism is used to describe the world in the regimes where the quantum properties of the gravitational field cannot be disregarded. This is because the quantum fluctuation of spacetime itself makes the notion of time unsuitable for writing physical laws in the conventional form of evolution laws in time.

This position led him to face the following problem: if time is not part of the fundamental theory of the world, then how does time emerge? In 1993, in collaboration with Alain Connes, Rovelli proposed a solution to this problem called the thermal time hypothesis. According to this hypothesis, time emerges only in a thermodynamic or statistical context. If this is correct, the flow of time is not fundamental, deriving from the incompleteness of knowledge. …

Rovelli's first book was on the Italian student political movements in the 1970s. He later refused Italy's compulsory military draft and was briefly detained. In 2021, he coordinated the Global Peace Dividend, an open letter signed by more than 50 Nobel Laureates, including the Dalai Lama, calling for all countries to negotiate a balanced cut on their military spending by 2% a year for the next five years, and put half the saved money in a UN fund to combat pandemics, the climate crisis, and extreme poverty.

On 1 May 2023, Rovelli gave a political speech at the large Italian Labour Day concert in Rome, inviting the youth to engage politically for the environment, economical equality and peace, and criticizing the Italian Defence Minister Guido Crosetto for what he claims was his direct involvement with what he calls the industrial military complex. The speech raised a large controversy. As a consequence, his invitation to represent Italy at the 2024 Frankfurt Book Fair was cancelled; the cancellation itself was widely criticized, leading to his re-invitation, and the resignation of the Italian Commissary for the Buchmesse. Rovelli repeated his call for reduced military spending and improved international cooperation following the outbreak of the Gaza war. That same year, he was one of the signatories of the International Peace Conference manifesto, which accuses the United States, the European Union, and NATO of being a driving force behind the Russian invasion of Ukraine.

Rovelli has written more than 200 scientific articles published in international journals. He has published two monographs on loop quantum gravity and several popular science books. His book, Seven Brief Lessons on Physics, has been translated into 41 languages.