Carlo Rovelli

Carlo Rovelli (born May 3, 1956) is an Italian theoretical physicist and writer who has worked in Italy, the United States and, since 2000, in France.

He is also currently a Distinguished Visiting Research Chair at the Perimeter Institute, and core member of the Rotman Institute of Philosophy of Western University.

He works mainly in the field of quantum gravity and is a founder of loop quantum gravity theory.

He has also worked in the history and philosophy of science.

He collaborates with several Italian newspapers, including the cultural supplements of the Corriere della Sera, Il Sole 24 Ore and La Repubblica.

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 use of LSD at this time with sparking his 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?"

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.

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.

In 1988, Rovelli, Lee Smolin and Abhay Ashtekar introduced a theory of quantum gravity called loop quantum gravity.

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.

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.

Similar conclusions had been reached earlier in the context of nonequilibrium statistical mechanics, in particular in the work of Robert Zwanzig, and in Caldeira-Leggett models used in quantum dissipation.

In 1994, Rovelli introduced the relational interpretation of quantum mechanics, based on the idea that the quantum state of a system must always be interpreted relative to another physical system (like the "velocity of an object" is always relative to another object, in classical mechanics).

The idea has been developed and analyzed in particular by Bas van Fraassen and by Michel Bitbol.

Among other important consequences, it provides a solution of the EPR paradox that does not violate locality.

Rovelli has expressed the main idea of relational quantum mechanics in the popular book Helgoland.

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.

Since 2000 he has been a professor at the Centre de Physique Théorique de Luminy of Aix-Marseille University in France.

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 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.

Rovelli won the second prize in the 2013 FQXi contest "It From Bit or Bit From It?"

His popular science book, Seven Brief Lessons on Physics, was originally published in Italian in 2014.

It has been translated into 41 languages and has sold over a million copies worldwide.

In 2019, he was included by Foreign Policy magazine in a list of 100 most influential global thinkers.