Homepage of Matthias Ludewig

Projects

On this page, I give an overview over research projects that I currently work on or that I have been working on in the past. If you are interested in learning more about these projects, do not hesitate to contact me.


String Geometry and Functorial Field Theory



Talks given about this project


Video The spinor bundle on loop space and its fusion product
Center for Quantum and Topological Systems at NYU Abu Dhabi
Video The stringor bundle of a string manifold
Mid-South Algebraic Topology and Geometry Workshop
Video The stringor bundle (by Konrad Waldorf)
"QFT and Cobordism" @ Center for Quantum and Topological Systems at NYU Abu Dhabi
Video The stringor bundle (by Konrad Waldorf)
Galileo Galilei Institute
Video Approaching string geometry through loop spaces (by Peter Kristel)
Mid-South Algebraic Topology and Geometry Workshop

Publications relevant to this project


arXiv A representation of the string 2-group, with Peter Kristel and Konrad Waldorf.
arXiv preprint
arXiv The spinor bundle on loop space.
arXiv preprint
arXiv The stringor bundle, with Peter Kristel and Konrad Waldorf.
arXiv preprint
arXiv The insidious bicategory of algebra bundles, with Peter Kristel and Konrad Waldorf.
arXiv preprint
arXiv Journal Lie 2-groups from loop group extensions, with Konrad Waldorf.
J. of Homotopy and Rel. Structures 19, pp 597-633, 2024
arXiv Journal Categories of Lagrangian Correspondences in Super Hilbert Spaces and Fermionic Functorial Field Theory.
SIGMA 20, paper no. 036, 2024
arXiv Journal The Clifford algebra bundle on loop space.
SIGMA 20, paper no. 020, 2024
arXiv 2-vector bundles, with Peter Kristel and Konrad Waldorf.
Accepted for publication in Higher Structures
arXiv Journal A framework for geometric field theories and their classification in dimension one, with Augusto Stoffel.
SIGMA 17, paper no. 072, 2021
arXiv Journal The Chiral Anomaly of the Free Fermion in Functorial Field Theory, with Saskia Roos.
Ann. Henry Poincaré 21, pp 1191-1233, 2020


Mathematics of Topological Insulators



Talks given about this project


Video Spectral aspects of topological matter with an eye on strings (by Guo Chuan Thiang)
Au & NZ Geometry Strings Fields Seminar
Video What is a Coarse Index, physically? (by Guo Chuan Thiang)
Global Noncommutative Geometry Seminar,

Publications relevant to this project


arXiv Coronas and Callias type operators in coarse geometry, with Ulrich Bunke.
arXiv preprint
arXiv Quantization of conductance and the coarse cohomology of partitions, with Guo Chuan Thiang.
arXiv preprint
arXiv Journal Coarse geometric approach to topological phases: Invariants from real-space representations, with Christoph Setescak and Caio Lewenkopf.
Phys. Rev. B 111, paper no. 104207, 2025
arXiv Book Coarse geometry and its applications in solid state physics.
Encyclopedia of Mathematical Physics, 2nd Edition, Editors: Emile Prodan, Elsevier
arXiv Journal Large-scale geometry obstructs localization, with Guo Chuan Thiang.
J. Math. Phys. 63, paper no. 91902, 2022
arXiv Journal Delocalized spectra of Landau operators on helical surfaces, with Yosuke Kubota and Guo Chuan Thiang.
Comm. Math. Phys. 395, pp 1211-1242, 2022
arXiv Journal Breaking symmetries for equivariant coarse homology theories, with Ulrich Bunke.
J. Geom. Phys. 201, paper no. 105214, 2024
arXiv Journal Gaplessness of Landau Hamiltonians on hyperbolic half-planes via coarse geometry, with Guo Chuan Thiang.
Comm. Math. Phys. 386, pp 87-106, 2021
arXiv Journal Cobordism invariance of topological edge-following states, with Guo Chuan Thiang.
Adv. Theor. Math. Phys. 26(3), pp 673-710, 2022
arXiv Journal Good Wannier bases in Hilbert modules associated to topological insulators, with Guo Chuan Thiang.
J. Math. Phys. 61, paper no. 061902, 2020


Path Integrals in Geometry and Physics



Publications relevant to this project


arXiv Journal A Short Proof of the Localization Formula for the Loop Space Chern Character of Spin Manifolds, with Zelin Yi.
J. Noncommut. Geom. 17(1), pp 189-210, 2023
arXiv Book Construction of the Supersymmetric Path Integral: A Survey.
Differential Geometry in the Large, Editors: Owen Dearricott, Wilderich Tuschmann, Yuri Nikolayevsky, Thomas Leistner, Diarmuid Crowley, Cambridge University Press
arXiv Journal The Chern Character of theta-summable Fredholm Modules over dg Algebras and the Supersymmetric Path Integral, with Batu Güneysu.
Adv. Math. 395, paper no. 108143, 2021
arXiv Book Heat Kernels as Path Integrals.
Space – Time – Matter, Editors: Jochen Brüning and Matthias Staudacher, de Gruyther
arXiv Journal The Fermionic integral on loop space and the Pfaffian line bundle, with Florian Hanisch.
J. Math. Phys 63, paper no. 123502, 2022
arXiv Journal A Rigorous Construction of the Supersymmetric Path Integral Associated to a Compact Spin Manifold, with Florian Hanisch.
Comm. Math. Phys 391, pp 1209-1239, 2022
arXiv Journal Heat kernel asymptotics, path integrals and infinite-dimensional determinants.
J. Geom. Phys. 131, pp 66-88, 2018
arXiv Journal Path Integrals on Manifolds with Boundary.
Comm. in Math. Phys. 354, pp 621-640, 2017


Heat Kernels and Geometric Invariants



Publications relevant to this project


arXiv Journal The Trace and the Mass of subcritical GJMS Operators.
Diff. Geom. Appl. 56, pp 95-109, 2018
arXiv Journal Asymptotic Expansions and Conformal Covariance of the Mass of Conformal Differential Operators.
Ann. Global Anal. and Geom. 52, pp 237-268, 2017
arXiv Journal Strong short-time asymptotics and convolution approximation of the heat kernel.
Ann. Global Anal. Geom. 55, pp 371-394, 2019