Normalizing renormalization (2)

Sophie Mutzel

Date(s) : 22/06/2023   iCal
17 h 00 min - 18 h 00 min

Renormalization is one of the most powerful conceptual frameworks in theoretical physics. Renormalization was first introduced as a systematic tool for subtracting ultraviolet divergences in perturbative quantum field theory at the end of the 1940s. The pioneering work of Kenneth Wilson gave it a physical meaning and tied the relation to statistical physics. His work dramatically changed the way we think about quantum field theories and earned him the Nobel Prize in 1982. The key idea of the renormalization group (RG) is that phenomena at different scales relate to one another. The theoretical framework often causes confusion among students attending quantum field theory classes (including myself). In this second part of my attempt to “normalize renormalization” I will recall how the algorithm of “doing physics” (which we apply to quantum field theories) leads us to the RG equations. We will then try to formalize this abstract picture by focussing on a specific regularization scheme, namely lattice regularization, which naturally provides a momentum cutoff. Performing RG transformations can be described by a flow in theory space. This flow can exhibit fixed points and we will see how the universal behaviour near fixed points helps us understand why our algorithm of doing physics works so well!



Le séminaire des doctorant⋅es de l’I2M et du CPT à Luminy regroupe chaque semaine les doctorant⋅es du site autour d’un exposé plus ou moins (in)formel, dans un cadre convivial. Il est évidemment ouvert aux étudiant⋅es de master et aux doctorant⋅es d’autres laboratoires.

C’est au rez-de-chaussée du bâtiment de « l’ancienne BU », dans la salle « Séminaire 2 » (au fond à gauche en sortant de l’escalier si vous venez de l’étage, au fond à droite si vous entrez par le rez-de-chaussée). Attention : l’entrée dans le labo nécessite un badge. En cas de souci (de type : être bloqué⋅e dehors), appeler le 04 91 26 95 91.

Salle Séminaire2 (RdC) Ancienne BU Luminy Site Sud


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