AVVISO DI SEMINARIO
Giovedì 14 febbraio 2019 - ore 15:00
Dipartimento di Fisica - Largo B.Pontecorvo, 3
Aula 248 - primo piano - Ed. C
(Dipartimento di Fisica - Pisa)
Terrà un seminario dal titolo:
“Symmetry-Improved 2PI Effective Action”
Abstract: The 2PI effective action is a powerful theoretical tool that resums automatically infinite sets of perturbation-theory contributions, in a consistent and systematic way. A major obstacle to its application to a wide range of situations was that symmetries are not encoded properly in the formalism, giving rise, for instance, to massive Goldtsone bosons. We solved this long-standing problem, in the case of global symmetries, by developing the so-called Symmetry-Improved 2PI (SI2PI) Effective Action. I will discuss its satisfactory field-theoretical properties and its application to the recently pointed out issue of IR divergences of the Standard-Model effective potential due to Goldstone bosons. I will finally show that the SI2PI effective potential is exactly invariant under renormalization-group running, as opposed to the more familiar 1PI case, which is so only up to higher orders.