Flowing in discrete gravity models and Ward identities: a review
Faculté des Sciences et Techniques (ICMPA-UNESCO Chair), Université d’Abomey-Calavi, 072 BP 50, Cotonou, Benin
2 Commissariat à l’Énergie Atomique (CEA, LIST), 8 Avenue de la Vauve, 91120, Palaiseau, France
Accepted: 30 July 2021
Published online: 29 September 2021
Ward–Takahashi identities are nonperturbative relations between correlation functions and arising from symmetries in quantum and statistical fields theories, as Noether currents conservation for classical theories. Since their historical origin, these identities were considered to prove the exact relation between counter-terms to all order of the perturbative expansion. Recently they have been considered in relation with nonperturbative renormalization group aspects for some classes of quantum field theories namely tensorial group field theories and matrix models, both characterized by a specific non-locality in their interactions, and expected to provide discrete models for quantum gravity. In this review, we summarize the state of the art, focusing on the conceptual aspects rather than technical subtleties, and provide a unified reflection on this novel and promising way of investigation. We attached great importance to the pedagogy and the self-consistency of the presentation.
© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2021