Mathematical Physics Group

The seminars begin at 2.30pm unless otherwise stated.

Oct 1th: Robinson Mancilla (ULB) - Aula S

Title: Quantum corrections to the near-extremal thermodynamics of (warped) BTZ black holes

Abstract: We study one-loop effects in BTZ and warped BTZ black holes, focusing on eigenmodes that become zero modes in the extremal throat. Our analysis is formulated in three-dimensional Topologically Massive Gravity. We compare the near-horizon and full-geometry eigenvalue problems and determine how the Schwarzian and rotational sectors are lifted at small temperature. By generalizing perturbation theory, we resolve a mismatch between the near-horizon and full-geometry rotational sectors previously reported in the literature. We show that rotational modes probe the throat as an open system, so their contribution cannot be determined from the throat alone but depends on boundary conditions in the full geometry.

Oct 22nd: Domenico Seminara (U. of Florence) - Aula S

Title: Quantum JT gravity in a box as a Pöschl–Teller scattering problem 

Abstract: I will discuss Jackiw–Teitelboim gravity with a Dirichlet wall at finite distance, the two-dimensional setting of finite-cutoff holography, and the TT̄ deformation. Quantizing the finite-cutoff phase space directly turns the theory into a Pöschl–Teller scattering problem for the geodesic length between the walls, and the disk partition function can be computed exactly. The energies are TT̄-deformed, but the density of states acquires non-perturbative corrections that are invisible near the asymptotic boundary and smooth the TT̄ truncation of the spectrum over a Planckian window where the horizon approaches the wall. I will discuss their geometric origin, the consistency checks (semiclassical action, one-loop, entropy, Wheeler–DeWitt), matter correlators, and what happens when the wall crosses the horizon. Based on arXiv:2607.01385. 

Nov 12th: Lorenzo Foscolo (Sapienza) - Aula S

Title: Special metrics on non-compact Calabi-Yau 3-folds 

Abstract: We present the construction of infinitely many examples of distinguished non-Kähler Hermitian metrics on non-compact Calabi-Yau 3-folds. These metrics solve a system of first-order PDEs which arises in theoretical physics as the common NS-NS sector of String Theory and is related to recent attempts to define notions of "canonical" metrics on non-Kähler Calabi-Yau manifolds. The examples we construct include infinitely many complete metrics obtained by deforming an asymptotically conical Kähler Ricci-flat metric in the direction of a non-trivial Äppli class and families of solutions on the ordinary double point and its smoothing that enjoy a cohomogeneity one symmetry (i.e. there is a symmetry group that acts with 1-dimensional orbit space). The talk is based on joint work with Mario Garcia-Fernandez. 

Nov 19nd: Pieter Bomans (DESY) - Aula Lagrange

Title: TBA

Abstract: TBA

Nov 26th (11:00 AM): Nikolay Bobev (KU Leuven) - Aula Monod

Title: TBA

Abstract: TBA

Dec 1st: Elisa Marieni (University of Southampton) - Aula Monod

Title: TBA

Abstract: TBA

Dec 3rd: Mario de Marco (ULB) - Aula Lagrange

Title: TBA

Abstract: TBA

Dec 10th: Jieming Lin (Imperial College)

Title: A Geometric Formulation of a-Maximisation

Abstract: In four-dimensional $\mathcal N=1$ superconformal field theories, $a$-maximisation determines the exact superconformal R-symmetry. In this talk, I will discuss its geometric formulation on the dual supergravity side using exceptional generalised geometry. This framework accommodates general supersymmetric backgrounds with non-trivial fluxes, while its vector- and hypermultiplet structures provide a direct link to the dual CFT and its deformations. The extremisation incorporates both mesonic and baryonic symmetries. After performing the baryonic extremisation, we can construct equivariant polyforms and use equivariant localisation to carry out the mesonic extremisation. If time permits, I will also discuss the mathematical connection between holographic $a$-maximisation and slope extremisation in Hesselink stratification.

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