I am a PhD student in mathematics at the University of Lille under the supervision of Alexis Virelizier since September 2023. I used to go by the name Matthew Jackson.
Cité Scientifique, M3
59650 Villeneuve-d'Ascq, France
Office: M3-236 ("Bureau quantique")
Telephone: +33 (0)3 20 43 48 69
Email: matthew.cellot[at]univ-lille.fr
My research concerns algebraic and quantum topology. In particular, I focus on 4-dimensional homotopy quantum field theories (a generalization of topological quantum field theories) and homotopy 3-types.
Quantum topology is a field that came about in the 1980s following remarkable discoveries by Jones, Drinfeld and Witten whose work (recognized by Fields medals awarded to each of them in 1990) dramatically renewed topology, in particular in low dimension. A fundamental notion in quantum topology is that of topological quantum field theory (TQFT) formulated by Witten. This notion originates in ideas from quantum physics and constitutes a framework that organizes certain topological invariants of manifolds, called quantum invariants, which are defined by means of quantum groups. Homotopy quantum field theories (HQFTs) are a generalization of TQFTs. The idea is to use TQFT techniques to study principal bundles over manifolds and, more generally, homotopy classes of maps from manifolds to a topological space X.
Turaev and Virelizier have constructed 3-dimensional HQFTs (by state-sum) when the space X is aspherical (i.e. its n-th homotopy groups of X are trivial for n>1) and Sözer and Virelizier have constructed 3-dimensional HQFTs when X is a 2-type (i.e. its n-th homotopy groups are trivial for n>2). Using state sum techniques, Douglas and Reutter constructed 4-dimensional TQFTs from spherical fusion 2-categories. The aim of this PhD project is to generalize these constructions (both from the topological and the algebraic viewpoint) to the case of 4-dimensional HQFTs with target a 3-type. In this case, the relevant algebraic structures for constructing such HQFTs should be spherical fusion 2-categories graded by a 2-crossed module.
"Higher path groupoids and the holonomy of formal power series connections", June 2025, arXiv:2506.23880 (submitted)
"Graded-fusion 2-categories and quantum homotopy invariants of 4-manifolds"
"4-dimensional homotopy quantum field theories and homotopy 3-types"
(future) Feb 2026 - Algebraic Topology seminar, UCLouvain
(future) Feb 2026 - Topology seminar, Université de Lille
Nov 2025 - Quantum Universe Attract. Workshop, Universität Hamburg
Sep 2025 - Higher Structures: Recent developments and applications, Universität Hamburg (see slides)
May 2025 - Algebraic Approaches to Mapping Class Groups of Surfaces, The University of Tokyo
May 2025 - FJ-LMI Seminar, The University of Tokyo (see slides)
Apr 2025 - Journées de Jeunes Chercheuses et Chercheurs en Topologie, Université Picardie Jules Verne
Nov 2024 - Séminaire des doctorants et post-doctorants, Université de Lille (see slides in French)
Jan 2024 - Topology seminar, University of Louisiana at Lafayette (see slides)
Sep 2023 - Topology seminar, Université de Lille
(future) Mar 2026 - Journées de topologie algébrique, géométrique et quantique en Picardie III, Université Picardie Jules Verne
(future) Mar 2026 - Winter braids XV, Aix-Marseille Université
Oct 2025 - Journée de topologie quantique, Université Paris-Cité
Sep 2025 - Higher Structures: Recent developments and applications, Universität Hamburg
May 2025 - Algebraic approaches to mapping class groups of surfaces, The University of Tokyo
Apr 2025 - Journées de Jeunes Chercheuses et Chercheurs en Topologie, Université Picardie Jules Verne
Mar 2025 - Journées de topologie algébrique, géométrique et quantique en Picardie II, Université Picardie Jules Verne
Feb 2025 - Winter braids XIV, Université de Bordeaux
Dec 2024 - Skein days, Journées thématiques de Cergy-Pontoise, CY Cergy Paris Université
Nov 2024 - Journée de topologie quantique, Université Paris-Cité
Oct 2024 - Séminaire itinérant de catégories, Université Paris-Cité
Oct 2024 - Higher structures in Noncommutative Geometry and Quantum Algebra, Université de Lille
Sep 2024 - Scottish Talbot on Algebra and Topology, Cairngorm Lodge, Glenmore, Scotland
Apr 2024 - Séminaire itinérant de catégories, Université de Lille
Mar 2024 - Journées de topologie algébrique, géométrique et quantique en Picardie, Université Picardie Jules Verne
Mar 2024 - Journée de topologie quantique, Université Paris-Cité
Feb 2024 - Winter braids XIII, Université de Montpellier
Oct 2023 - Conférence du GDR Théorie de l'Homotopie et Applications, Université de Lille
Oct 2023 - Séminaire itinérant de catégories, Université du Littoral à Calais
Mar 2023 - Building-up differential homotopy theory at Aizu, The University of Aizu
Feb 2023 - 18th East Asian Conference on Geometric Topology, online
Nov 2022 - International conference on "Topology and its Applications to Engineering and Life Science", online
Mathématiques et biostatistiques (24h TD) L2 Sciences et la vie
Algèbre et analyse élémentaires 2 (36h TD) L1 Physique
Tutorat (24h TD) L1-L2-L3 Mathématiques
Algèbre et analyse élémentaires 2 (36h TD) L1 Physique
Internship supervisor for Valentin Gianesello, L1 Physique
"Constructions of 2-holonomy functors", ARPE report, 2023, under the supervision of Toshitake Kohno
"Sur la topologie des surfaces algébriques réelles non singulières de degré au plus 5 dans RP^3", master's thesis, 2022 (in French), under the supervision of Ilia Itenberg
"The invariance of knot lattice homology", first year master's project, 2021
"Contrefaçon d'une œuvre musicale : comment déterminer le plagiat ?", research project in law and mathematics, 2023, with Thomas Hum (see poster)