Carlo Rovelli is an Italian physicist who has worked in Italy, the USA, and France. His work is mainly in the field of quantum gravity. He is among he founders of the Loop Quantum Gravity theory.
Carlo Rovelli was born in Verona, Italy in 1956. In the 70' he actively participated to the student's political upraising in the Italian universities. He was involved with the free political radios Radio Alice in Bologna and Radio Anguana in Verona, which he contributed to found. In conjunction to his political activity, he was charged, and later discharged, for crimes of opinon related to the book "Fatti Nostri", which he co-authored with Enrico Palandri, Maurizio Torrealta and Claudio Piersanti. In 1981 he graduated with a BS/MS in Physics at the University of Bologna and in 1986 he obtained his PhD at the University of Padova, Italy. He refused to the serve in the military service, which was compulsory in Italy at the time, and was briefly detained in 1987 for this reason. He held postdoctoral positions at the Universities of Rome and Yale. He was then in the faculty of University of Pittsburgh from 1990 to 2000. He is currently at the Université de la Méditerranée, in the Centre de Physique Théorique, in Marseille, France. He has also long been affiliated Professor in the Department of History and Philosophy of Science of the University of Pittsburgh, USA.
In 1988 Carlo Rovelli, Lee Smolin and Abhay Ashtekar introduced a theory of quantum gravity denoted loop quantum gravity. In 1995 Rovelli and Smolin obtained an explicit 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 at the very small scale. In 1997, Carlo Rovelli and Michael Reisenberger have introduced a "sum over surfaces" formulation of theory, which has since evolved into the currently popular covariant "spinfoam" version of loop quantum gravity. The theory is today considered a leading candidate for a quantum theory of gravity, and finds tentative applications in areas such as quantum cosmology and quantum black hole physics.
In his 2004 book "Quantum Gravity", Rovelli has developed a formulation of classical and quantum mechanics that does not make any explicit reference to the notion of "time". Rovelli defends the idea that such a timeless formalism is needed 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 make the notion of time unsuitable for writing physical laws in the conventional form of evolution laws in time.
This position has lead 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 has proposed a solution to this problem called the thermal time hypothesis. According to this hypothesis, time emerges only in a thermodynamical or statistical context. If this were correct the flow of time would be an illusion, deriving from the incompleteness of knowledge.
In 1994 Rovelli introduced the relational interpretation of quantum mechanics, based on the idea that the quantum state of a system must always to be interpreted as 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.
Rovelli has also worked in the history and philosophy of science. He has written a book on the Greek philosopher Anaximander which was published in France in June 2009 and is being translated in English and Greek. It is expected to be published in the US, Greece and Italy during 2011. The book analyses the main aspects of scientific thinking, and articulates Rovelli's views on science, using the historical figure of Anaximander as a starting point. Anaximander is presented in the book as a main initiator of scientific thinking. For Rovelli, science is continuous process of exploring novel possible views of the world; this happens via a "learned rebellion", which always builds and relies on previous knowledge, but at the same time does not hesitate continuously questioning aspects of the received knowledge. Therefore the foundation of science is not certainty, but, to the very opposite, a radical uncertainty about our own knowledge, or equivalently, an acute awareness of the extent of our ignorance.
Rovelli discusses his religious views in his book on Anaximander. He is clearly an atheist. He argues that the conflict between rational/scientific thinking and structured religion may find periods of truces (because "there is no contradiction between solving the Maxwell equations and believing that God created Heavens and Earth"), but is ultimately unsolvable, because (most) religions demands the acceptance of some unquestionable Truths, while scientific thinking is based on the continuous questioning of any truth. Thus, for Rovelli the source of the conflict is not the pretense of science to give answers (the universe, for Rovelli, is full of mystery, and a source of awe and emotions), but, to the very opposite, the source of the conflict is the acceptance of our ignorance at the foundation of science, with clashes with the pretense of (most) religious institutions to be depositaries of knowledge.
