[Zoom Seminar] Perturbative and non-perturbative studies in QFTs | Dr. Giacomo Sberveglieri (University of Bern)

The speaker: Dr. Giacomo Sberveglieri (University of Bern)

Title:  Perturbative and non-perturbative studies in QFTs

Abstract:

Quantum field theory has produced many high-precision results. However, despite extensive research, analytical methods face significant challenges in addressing strongly coupled regimes of QFT. In this talk, I will present how, during my research, I aim to provide insights into these regions. I will start with an introduction on the nature of perturbative series and their relation with non-perturbative effects. Then, I will focus on N-components φ^4 theory in two and three dimensions. By means of the perturbative series of various observables that we have computed up to order eight, we investigated the critical regime and phase diagrams of these theories and their dependence on the choice of scheme. We observed a rich structure of dualities and provided a comprehensive collection of our perturbative results. Later, I will move to models in which singularities in the Borel plane are obstructing the standard Borel resummation. I'm going to discuss the interplay between resurgent properties and the 1/N expansion in various integrable field theories with renormalons. Direct QFT calculation, analytical and numerical techniques on the Thermodynamic Bethe Ansatz equations allowed us to answer several questions, finding different outcomes. Lastly, I will concentrate on conformal field theories in sectors of large global charge. After a brief and pedagogical introduction to the large quantum number expansion, I will present concrete examples (of CFTs and defect CFTs) that are objects of my past, present, and future research.

Date and time: 14th January Tuesday at 17:30

Location: L4F15