PIRSA:21100048

Aspects of ghost-free nonlocal field theories

Buoninfante, L. (2021). Aspects of ghost-free nonlocal field theories. Perimeter Institute. https://pirsa.org/21100048

Buoninfante, Luca. Aspects of ghost-free nonlocal field theories. Perimeter Institute, Oct. 28, 2021, https://pirsa.org/21100048 

          @misc{ pirsa_PIRSA:21100048,
            doi = {10.48660/21100048},
            url = {https://pirsa.org/21100048},
            author = {Buoninfante, Luca},
            keywords = {Quantum Gravity},
            language = {en},
            title = {Aspects of ghost-free nonlocal field theories},
            publisher = {Perimeter Institute},
            year = {2021},
            month = {oct},
            note = {PIRSA:21100048 see, \url{https://pirsa.org}}
          }

Luca Buoninfante Nordita - Nordic Institute for Theoretical Physics

DOI 10.48660/21100048
Collection
Talk Type Scientific Series
Subject

Abstract

In this talk I introduce nonlocal (infinite derivative) field theories. First of all, I discuss how and which principles of quantum field theory are affected when higher-order derivative operators are taken into account in a Lagrangian. In particular, I focus on the issue of unitarity and on how to make higher-derivative theories healthy by means of non-polynomial differential operators. I extend the treatment to the gravity sector and consider nonlocal theories whose graviton propagators are ghost-free, and explore the possibility of regularizing singularities. Next, I discuss some recent progress in proving perturbative unitarity for a very general class of nonlocal field theories. Finally, I will make some remarks on nonlocality and quantum gravity.