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

He has also worked in the history and philosophy of science, formulating the Relational quantum mechanics and the notion of Thermal Time.

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

[8] 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.

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.

In 1993, in collaboration with Alain Connes, Rovelli proposed a solution to this problem called the thermal time hypothesis.

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.

"[20] In 2017, Rovelli elaborated further upon the subject of relative information, writing that: In nature, variables are not independent; for instance, in any magnet, the two ends have opposite polarities.

Before “energy,” “matter,” or even “entity.”[21]Rovelli has written a book on the Greek philosopher Anaximander, published in France, Italy, US[22] and Brazil.

The book analyses the main aspects of scientific thinking and articulates Rovelli's views on science.

[24] The foundation of science, therefore, is not certainty but the very opposite, a radical uncertainty about our own knowledge, or equivalently, an acute awareness of the extent of our ignorance.

He argues that the conflict between rational/scientific thinking and structured religion may find periods of truce ("there is no contradiction between solving Maxwell's equations and believing that God created Heaven and Earth"),[26] but it is ultimately unsolvable, because most religions demand the acceptance of some unquestionable truths, while scientific thinking is based on the continuous questioning of any truth.

In 2021, he coordinated the Global Peace Dividend, an open letter signed by more that 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.

[28] 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 his direct involvement with the industrial military complex.

[31] Rovelli repeated his call for reduced military spending and improved international cooperation following the outbreak of the 2023 Israel–Hamas war.