Séminaires : Séminaire de Topologie

Equipe(s) : tga,
Responsables :Catherine Gille et Najib Idrissi
Email des responsables :
Salle : 1016
Adresse :Sophie Germain
Description

Un plan d’accès est disponible ici. Pour vous inscrire à la liste de diffusion du séminaire, veuillez vous rendre à cette adresse.

Le séminaire de topologie évolue. Des après-midi de topologie seront organisées tout au long de l'année (en collaboration avec USPN) et nous vous en tiendrons informé(e)s sur cette liste de diffusion.


Orateur(s) David Reutter - ,
Titre Semisimple topological quantum field theories and exotic smooth structure
Date01/12/2020
Horaire10:45 à 11:45
Diffusion
RésumeA major open problem in quantum topology is the construction of an oriented 4-dimensional topological quantum field theory (TQFT) in the sense of Atiyah-Segal which is sensitive to smooth structure. In this talk, I will sketch a proof that no semisimple field theory can achieve this goal and that such field theories are only sensitive to the homotopy types of simply connected 4-manifolds. In this context, 'semisimplicity' is a certain algebraic condition applying to all currently known examples of vector-space-valued oriented 4-dimensional TQFTs, including 'unitary field theories' and 'once-extended field theories' which assign algebras or linear categories to 2-manifolds. If time permits, I will give a concrete expression for the value of a semisimple TQFT on a simply connected 4-manifold and explain how the presence of `emergent fermions’ in a field theory can make it sensitive to more than the homotopy type of a non-simply connected 4-manifold. This is mainly based on arXiv:2001.02288.
Sallehttps://bbb-front.math.univ-paris-diderot.fr/recherche/naj-jfp-o52-viy
AdresseSophie Germain
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