Spinfoams and the discreteness of time

          @misc{ scivideos_PIRSA:25060063,
            doi = {10.48660/25060063},
            url = {https://pirsa.org/25060063},
            author = {Vidotto, Francesca},
            keywords = {},
            language = {en},
            title = {Spinfoams and the discreteness of time},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2025},
            month = {jun},
            note = {PIRSA:25060063 see, \url{https://scivideos.org/index.php/pirsa/25060063}}
          }
          

Abstract

The covariant dynamics of Loop Quantum Gravity answers the question of what we can in principle predict and observe in quantum gravity. It features a characteristic discrete quantum evolution, as proposed in a seminal paper by Smolin and Markoupoulou in 1997. Spinfoam transition amplitudes are local exactly thanks to this form of discreteness. Another property of the amplitudes is to be exactly finite when their formulation includes a cosmological constant: this adds further to the fundamental discreteness of spacetime quanta, and again it is a feature rooted in Lee’s Smolin seminal works.