Month: October 2021

On November 2 we will have a seminar by

Shota Komatsu (CERN)

Title: Three tales of de Sitter

Abstract:
I will discuss the fundamentals of quantum field theory on a rigid de Sitter space. First, I will show that the perturbative expansion of late-time correlation functions to all orders can be equivalently generated by a non-unitary Lagrangian on a Euclidean AdS geometry. This finding simplifies dramatically perturbative computations, as well as allows us to establish basic properties of these correlators, which comprise a Euclidean CFT. Second, I use this to infer the analytic structure of the spectral density that captures the conformal partial wave expansion of a late-time four-point function, to derive an OPE expansion, and to constrain the operator spectrum. Third, I will prove that unitarity of the de Sitter theory manifests itself as the positivity of the spectral density. This statement does not rely on the use of Euclidean AdS Lagrangians and holds non-perturbatively.

Meeting information:
November 2, 2021 @ 4:00PM Italian time (CET)
Zoom Meeting https://l.infn.it/stringwebseminar

You can watch the recording at the link https://pandora.infn.it/public/shota-komatsu.

On October 19 we will have a seminar by

Sergio Benvenuti (INFN Trieste – SISSA)

Title: Dualities from deconfinement

Abstract:
We prove dualities involving four dimensional N=1 gauge theories with rank-2 matter. We assume only elementary dualities, that is Seiberg and Intriligator-Pouliot dualities. The strategy is to use multiple times elementary S-confining dualities and elementary electric-magnetic dualities, until the desired dual theory is reached. As a first example, we derive the Wess-Zumino description of all S-confining single node quivers with rank-2 matter. As a second example, we derive a ‘fully deconfined’ dual of USp(2N) with an antisymmetric and 2F fundamental fields, then use it to prove a self-duality valid at F=4. These results are based on ongoing work with Stéphane Bajeot, and uplift 3d results obtained with Ivan Garozzo and Gabriele Lo Monaco.

Meeting information:
October 19, 2021 @ 4:00PM Italian time (CEST) [NOTE the different time wrt previous seminar]
Zoom Meeting https://l.infn.it/stringwebseminar

You can watch the recording at the link https://pandora.infn.it/public/sergio-benvenuti.

On October 5 we will have a seminar by

Lorenzo di Pietro (Università di Trieste)

Title: Conformal boundary conditions for free fields

Abstract:
I will discuss the problem of classifying (interacting) conformal boundary conditions for the simplest bulk conformal field theories: free fields. I will mention concrete examples based on perturbation theory, and then describe results using the numerical conformal bootstrap approach, specifically in the case of a scalar field in four and three bulk dimensions.

Meeting information:
October 5, 2021 @ 2:30PM Italian time (CEST)
Zoom Meeting https://l.infn.it/stringwebseminar

You can watch the recording at the link https://pandora.infn.it/public/lorenzo-dipietro.