I am a French mathematician, Full Professor of Mathematics at Université Paris-Saclay (Laboratoire de Mathématique d’Orsay). I am also a writer. My first novel Éducation tropicale (Editions Gallimard) was published in 2018 and was awarded the Albert Bernard prize.
Latest news:
- 26/01/26: My book Microlocal analysis in Hyperbolic Dynamics and Geometry (Cours spécialisés de la SMF, 2025) is officially out! It can be purchased from the SMF online bookshop here.
- 09/01/26: Open two-year postdoc position, starting September 26, see MathJobs for more information. Deadline for application: February 1, 2026.
EDIT: Due to a technical issue with the Paris-Saclay MathsJobs account, it is currently no longer possible to apply through MathsJobs. We are working to resolve this issue as soon as possible. For this reason, the application deadline has been postponed by a week, until February 8. In the meantime, applications (and reference letters) can be sent to me directly by email (thibault dot lefeuvre1 at universite-paris-saclay dot fr). - 09/01/26: I have posted on the arXiv a review of my recent work with A. Chabert and L. Charles on the magnetic Laplacian over hyperbolic surfaces. This is to be published in the Proceedings of the Journées Equations aux Dérivées Partielles.
2025
- 19/11/25: With Mihajlo Cekić, Andrei Moroianu and Uwe Semmelmann, we have posted on the arXiv a new paper establishing the Pestov identity on the frame bundle of a Riemannian manifold. We show that all previously known Pestov identities on associated homogeneous fibrations (such as the unit tangent bundle) can be derived from this general result. This provides a conceptual framework for establishing general Pestov-type identities and will have further applications in forthcoming work by Louis Beaufort and Sebastián Muñoz-Thon on the magnetic X-ray transform.
- 14/10/25: We have just posted on the arXiv a new paper with Karen Butt, Alena Erchenko, Tristan Humbert and Amie Wilkinson. We study a new invariant of closed negatively curved manifolds that we call the marked Poincaré determinant: it is the data of the determinant of the unstable Poincaré map along each closed geodesic, marked by the free homotopy classes of the manifold. We prove that, near hyperbolic metrics in dimension 3, this invariant determines the metric up to homothety. The key ingredient of the proof is the injectivity of the Lichnerowicz Laplacian on trace-free diverge-free symmetric 2-tensors at a hyperbolic metric in dimension 3, which is of independent interest.
- 20/05/25: I am thrilled to announce that the final version of my book on Microlocal Analysis in Hyperbolic Dynamics and Geometry is now complete. The book is to be published this year by the Société Mathématique de France.
- 14/05/25: We have just uploaded our new paper on the arXiv with Laurent Charles on semiclassical defect measures of magnetic Laplacians on hyperbolic surfaces. In this work, we study quantum limits of eigenstates of the magnetic Laplacians and show that three distinct regimes appear, depending on the value of the energy (low energy, critical energy, high energy). The underlying classical motion—the magnetic flow— is either conjugate to a rotation flow, the horoyclic flow, or the (Anosov) geodesic flow at these energies. In particular, at the critical energy, we prove Quantum Unique Ergodicity along with a quantitative rate of convergence of eigenstates to the Liouville measure.
- 04/11/24: I am co-organizing with Andrei Moroianu a workshop on Special structures in dynamics and geometry at Jussieu (Paris) from January 8 to 10, 2025. It is funded by my grant EMERGENCE from Sorbonne Université. See here for details. You can register to the workshop by emailing me or Andrei.
- 25/10/24: Open two-year postdoc position at Jussieu (Paris), starting in September 2025. See here for details.
- 05/09/24: I am the laureate of the ERC Starting Grant ADG (Analytic methods for Dynamical systems and Geometry)!
THIBAULT LEFEUVRE 