Mathematical physics seminar
Date: Tuesdays 11:15-12:45 Uhr
Venue: 1.023 (BMS Room, Haus 1, ground floor), Rudower Chaussee 25, Adlershof, 12489 Berlin
Organiser: Gaëtan Borot
Wintersemester 2025-26
21. Oktober 2025
Matijn Francois (University of Geneva)
On the open topological strings/spectral theory correspondence
The topological string/spectral theory correspondence establishes a precise, non-perturbative duality between topological strings on local Calabi–Yau threefolds and the spectral theory of quantized mirror curves. This duality has been rigorously formulated for the closed string sector, but the open string sector is less understood. In this talk, I will explain how one can use open-string partition functions to construct true eigenfunctions for the quantized mirror curve of local F₀. We will then discuss the four-dimensional limit, underlining the implications of the topological string/spectral theory correspondence for spectral problems relating four-dimensional supersymmetric gauge theories to the quantization of their Seiberg–Witten curves.
28. Oktober 2025
Lasse Merkens (HU)
Renormalization group flows from defects in N = 1 minimal models
Leveraging the structure of non-invertible symmetries, we construct a family of
renormalization group flows connecting N = 1 superconformal minimal models:
SM(p, kp + I) → SM(p, kp − I). The triggering operator is G−1/2ϕ(1,2k+1). A key ele-
ment of our argument is that the topological defect lines of the bosonic coset theory
persist in the fermionic case. These flows represent a supersymmetric generalization
of the Virasoro flows discovered by Tanaka and Nakayama and include the previ-
ously known unitary flows (Pogossyan, k = 1, I = 2) as a special case. Furthermore,
we demonstrate the completeness of this family; any flow between models SM(p, q)
and SM(p, q′) can be obtained by composing these fundamental flows.
4. November 2025
Xavier Blot (Unversiteit van Amsterdam)
On the DR-DZ equivalence, and beyond
Witten’s conjecture, proved by Kontsevich, predicted that the Gromov–Witten invariants of a point are governed by the KdV hierarchy. In this talk, I will explain how the DR–DZ equivalence extends this result by constructing the Dubrovin–Zhang (DZ) hierarchy, which governs the Gromov–Witten invariants of any smooth projective variety (and more generally, any cohomological field theory). I will also discuss the equivalence between the DZ and Double Ramification (DR) hierarchies, and, if time allows, their equivalence to new hierarchies associated with the Chiodo class.
This is based on joint works with Danilo Lewanski, Adrien Sauvaget and Sergey Shadrin.
11. November 2025
Taro Kimura (Université Bourgogne Europe)
Non-perturbative Schwinger-Dyson equation for DT/PT vertices
Non-perturbative Schwinger-Dyson (SD) equation is a discrete analog of the loop equation appearing in matrix models and related models. It was initially discussed for the gauge theory partition function and, as in the case of the matrix models, it has a close relation to the underlying infinite-dimensional symmetry of the system. In this talk, I'd like to discuss the non-perturbative SD equation for the higher-dimensional gauge theory partition function, interpreted as the generating function of the DT and PT invariants (DT/PT vertices) for CY3 and CY4 varieties, and address its underlying quantum algebraic structure, which is a consequence of geometric representation theory of the corresponding algebra.
18. November 2025
Piotr Sulkowski (Warsaw University)
Wall-crossing, Schur indices and symmetric quivers
I will show that symmetric quivers encode various
observables of 4d N=2 theories related to wall-crossing phenomena. The
observables in question include (wild) Donaldson-Thomas invariants, as
well as Schur indices, which at the same time are known to reproduce
characters of 2d conformal field theories. Furthermore, symmetric
quivers of our interest encode 3d N=2 theories, therefore all these
relations can be interpreted as a web of dualities between 2d, 3d, and
4d systems.
25. November 2025
Gaëtan Borot (HU Berlin) - (date could be moved!)
Panorama of matrix models and topological recursion I
This is crash course which aims at explaning various aspects of: random matrix ensembles and Coulomb gases, loop equations, spectral curves, topological recursion, maps, free probability, how they fit together and pose some open problems.
2. Dezember 2025
Nikolay Barashkov (MiS Leipzig)
Small deviations of Gaussian multiplicative chaos and the free energy of
the two-dimensional massless Sinh-Gordon model
We derive a bound on the probability that the total mass of Gaussian multiplicative
chaos measure obtained from a Gaussian field with zero spatial average, is small. We also give the probabilistic path integral formulation of the massless Sinh-Gordon model on a torus of side length R, and study its partition function R tends to infinity. We apply the small deviation bounds for Gaussian multiplicative chaos to obtain lower and upper bounds for the logarithm of the partition function, leading to the existence of a non-zero and finite subsequential infinite volume limit for the free energy.
9. Dezember 2025
Gaëtan Borot (HU Berlin) - (date could be moved!)
Panorama of matrix models and topological recursion II
This is crash course which aims at explaning various aspects of: random matrix ensembles and Coulomb gases, loop equations, spectral curves, topological recursion, maps, free probability, how they fit together and pose some open problems.
16. Dezember 2025
Dang Dang (HU Berlin)
Koszul duality in twisted QFTs
This talk gives an introduction to twisting procedures in supersymmetric field theories, with an emphasis on their modern mathematical formulation. We will then review the notion of Koszul duality, explaining how it captures dual descriptions of local operators and boundary conditions in twisted quantum field theories. Finally, we illustrate these ideas in the case of the B-twist of a two-dimensional N=(2,2) theory, where the resulting topological model leads to a familiar differential graded algebra of polyvector fields and its Koszul dual.
6. Januar 2026
Gaëtan Borot (HU Berlin) - (date could be moved!)
Panorama of matrix models and topological recursion III
This is crash course which aims at explaning various aspects of: random matrix ensembles and Coulomb gases, loop equations, spectral curves, topological recursion, maps, free probability, how they fit together and pose some open problems.
13. Januar 2026
Kein Seminar
20. Januar 2026
Cancelled
27. Januar 2026
Maciej Dolega (Institute of Mathematics, Polish Academy of Sciences)
Discrete N-particle systems at high temperature through Jack generating functions
We discuss random discrete N-particle systems with the deformation (inverse temperature) parameter θ. We find necessary and sufficient conditions for the Law of Large Numbers as their size N tends to infinity simultaneously with the inverse temperature going to zero. We apply the general framework to obtain the LLN for a large class of Markov chains of N nonintersecting particles with interaction of log-gas type, and the LLN for the multiplication of Jack polynomials, as the inverse temperature tends to zero. We express the answer in terms of novel one-parameter deformations of cumulants and discuss their relation to quantized free probability and continuous log-gas systems. If time permits, we will discuss a crystallization phenomenon observed in this regime and describe it in terms of the real-rootedness of certain special functions. Based on joint work with Cesar Cuenca.
3. Februar 2026
Cancelled
10. Februar 2026
Andrea Brini (Sheffield University)
On the conifold gap for the local projective plane
The conifold gap conjecture asserts that the polar part of the Gromov-Witten potential of a Calabi-Yau threefold near its conifold locus has a universal expression described by the logarithm of the Barnes G-function. In this talk I will describe a proof of the conifold gap conjecture for the local projective plane, whereby the higher genus conifold Gromov-Witten generating series of local P2 are related to the thermodynamics of a certain statistical mechanical ensemble of repulsive particles on the positive half-line. As a corollary, this establishes the all-genus mirror principle for local P2 through the direct integration of the BCOV holomorphic anomaly equations.
Semesterpause
Sommersemester 2026
21. April 2026
Pierrick Bousseau (Oxford University)
TBA
28. April 2026
TBA
5. Mai 2026
Damien Simon (Sorbonne Universite)
TBA
12. Mai 2026
TBA
19. Mai 2026
TBA
26. Mai 2026
Nikolai Kuchumov (Abo Akademi)
TBA
2. Juni 2026
TBA
9. Juni 2026
TBA
16. Juni 2026
Bertrand Eynard (IPhT CEA Saclay)
TBA
23. Juni 2026
Anna Hartkopf (FU Berlin, MIP.labor)
TBA
30. Juni 2026
TBA
7. Juli 2026
Alexander Alexandrov (IBS Pohang)
TBA
14. Juli 2026
TBA