Mardi 2 Décembre 2025, 11:00 à DPT-PHYS-ENS, amphi Jaurès - 29 reu d'Ulm 75005 PARIS	COLLOQUIUM-ENS (Colloquium of the Physics Department of ENS)	physics
Hugo Duminil-Copin ( Université de Genève et IHES, lauréat de la médaille Fields 2022 )	Large-scale behaviour of the four-dimensional φ⁴ model
Abstract:	In this talk, we will discuss the scaling limits of spin fluctuations in four-dimensional Ising-type models with nearest-neighbor ferromagnetic interaction at or near the critical point are Gaussian and its implications from the point of view of Euclidean Field Theory.

Mardi 2 Décembre 2025, 11:00 à LPTHE, LPTHE library	SEM-LPTHE (Séminaire du LPTHE)	hep-th
Godwin Martin ( ICTS Bengaluru )	An Exterior Field Theory for Hawking Radiation
Abstract:	How should one understand the physics of field theories living around a black hole? We know since Einstein that black holes suck in everything that is thrown at them (dissipation into the black hole). But since Hawking, we also know that black holes radiate (Hawking fluctuations of the black hole). Can one set up a field-theoretic description in the exterior of a black hole accounting for both these effects? I will present an affirmative answer to this question (for an AdS Schwarzschild black brane) and try to explain how the black hole modifies the Feynman rules of the field theory outside.

Mardi 2 Décembre 2025, 11:00 à IPHT, Amphi Claude Bloch, Bât. 774	IPHT-GEN (Séminaire général du SPhT)
Jesse Thaler ( MIT )	TBA

Mardi 2 Décembre 2025, 11:30 à LPENS, L378	ENS-BIOPHYS (ENS Biophysics Seminar)	physics.bio-ph
Matthias Merkel ( CPT Marseille, Turing Center for Living Systems )	TBA

Jeudi 4 Décembre 2025, 10:00 à IHP, Room Yvette Cauchois (Perrin building)	RENC-THEO (Rencontres Théoriciennes)	hep-th
Andrew O'bannon	TBA
Abstract:	TBA

Lundi 8 Décembre 2025, 14:00 à IHES, Amphithéâtre Léon Motchane ( Séminaire Géométrie et groupes discrets )	MATH-IHES (TBA)	math
Andrea Seppi ( Università di Torino )	Topology of Properly Convex Projective Manifolds of Dimension Four (and Higher)
Abstract:	I will present several results on the topology of closed manifolds of dimension at least 4 that admit a (real) properly convex projective structure, all related to a vanishing theorem of Kobayashi from 1984 for the rational Pontryagin classes. In arbitrary dimensions, I will outline a classification of locally symmetric manifolds admitting properly convex projective structures. Focusing on dimension 4, I will then present a result on the geometric decomposition which is the analogue of a theorem of Benoist in dimension 3, and the construction of examples that realize all possible positive values of the Euler characteristic. Based on joint work with Stefano Riolo and Leone Slavich.

Lundi 8 Décembre 2025, 16:00 à IHES, Amphithéâtre Léon Motchane ( Séminaire Géométrie et groupes discrets )	MATH-IHES (TBA)	math
Thibault Lefeuvre ( Université Paris-Saclay )	The spectrum of Anosov representations
Abstract:	: I will report on an ongoing project in collaboration with Yannick Guedes Bonthonneau and Tobias Weich. The goal of this work is to define a natural spectrum associated with Anosov representations, consisting of complex hypersurfaces in the complexified dual Cartan subalgebra. The leading hypersurface corresponds to a well-known object in the literature — the so-called critical hypersurface of the representation. To some extent, this spectrum generalizes a similar notion in the rank-one case, known as the set of Pollicott-Ruelle resonances (and the leading resonance), which is known to encode the exponential decay of correlations, among other properties. I will describe the main consequences of this spectral approach, namely the meromorphic extension (to the full complexified dual Cartan subalgebra) of dynamical zeta functions and Poincaré series associated with the representation. If time permits, I will discuss specific values of these functions, the sharp quantitative decay of correlations for the refraction flow, and the perspectives for future work.

Mardi 9 Décembre 2025, 10:45 à LPTMC, campus Jussieu, couloir 12-13, 5ème étage, salle 5-23	SEM-LPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée)	cond-mat
Julien Randon-Furling	TBA

Mercredi 10 Décembre 2025, 10:30 à IHES, Amphithéâtre Léon Motchane	SEED (Seed Seminar of Mathematics and Physics)	math-ph
Jesper Jacobsen ( LPENS, École normale supérieur )	TBA

Mercredi 10 Décembre 2025, 11:45 à IHES, Amphithéâtre Léon Motchane	SEED (Seed Seminar of Mathematics and Physics)	math-ph
Lucas Rey ( DMA, Ens )	The near-critical dimer model and the sine-Gordon field
Abstract:	The study of critical models is of the more active areas of statistical mechanics. Regarding the dimer model, the convergence of the critical model towards the Gaussian free field was obtained around 25 years ago by Kenyon. More recently, perturbations of the critical model known as near-critical models have been considered, and some convergence results have been obtained, in particular for the Ising model. Convergence results have also been obtained for the near-critical dimer model, which did not allow to identify the limiting field, even though it was conjectured to be the sine-Gordon field. I will present a derivation of the limit using discrete massive holomorphy techniques, which expresses the limiting field as the solution of a certain Dirichlet problem associated with a massive Dirac operator. I will finally explain how to relate this field to the sine-Gordon field. This is based on an ongoing work with Nathanaël Berestycki and Scott Mason.

Mercredi 10 Décembre 2025, 13:30 à DPT-PHYS-ENS, ConfIV (E244) - 24 rue Lhomond 75005 PARIS	COLLOQUIUM-ENS (Colloquium of the Physics Department of ENS)	physics
Huelga	TBA
Abstract:	TBA

Jeudi 11 Décembre 2025, 11:00 à IHES, Amphithéâtre Léon Motchane	MATH-IHES (TBA)	math
Lambert A'campo ( IHES )	The de Rham Property of Automorphic Galois Representations over CM Fields
Abstract:	In joint work in progress with Hevesi, Thorne and Whitmore, we prove that automorphic Galois representations over CM fields are de Rham and have the expected Hodge--Tate weights. The novelty of our result is that we do not impose any assumptions on the residual mod p Galois representation. To achieve this, we prove a theorem on the cohomology of certain unitary Shimura varieties, which gives a bound on the maximal order of a torsion class in the lower half of degrees of cohomology. After placing this theorem in the right context and discussing its proof, I will sketch how it relates to the de Rham property of automorphic Galois representations.

Jeudi 11 Décembre 2025, 14:00 à LPTMC, Jussieu, LPTMC seminar room, towers 13-12, 5th floor, room 523	SEM-LPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée)	cond-mat
Nicolas Laflorencie ( LPT Toulouse )	MBL?

Jeudi 11 Décembre 2025, 14:00 à LPTMC, campus Jussieu, couloir 12-13, 5ème étage, salle 5-23	SEM-LPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée)	cond-mat
Antonio Picano ( Collège de France )	TBA

Vendredi 12 Décembre 2025, 12:00 à LPENS, L378	ENS-BIOPHYS (ENS Biophysics Seminar)	physics.bio-ph
Michael Murrell ( Yale University )	TBA

Vendredi 12 Décembre 2025, 14:00 à LPENS, L378	FORUM-ENS (Forum de Physique Statistique @ ENS)	cond-mat.stat-mech
Arthur Alexandre ( EPFL, Swiss Institute of Bioinformatics )	From transport in channels to population evolution: how heterogeneities shape dynamics
Abstract:	In this seminar, I will discuss two problems where effective descriptions capture the essential mechanisms at play: one from hydrodynamics and one from population genetics. In hydrodynamics, Taylor dispersion describes the enhanced spreading of particles in a fluid due to the combined effects of diffusion and flow. We show how this phenomenon can be understood in tortuous, highly corrugated channels using an effective model that captures the main transport properties, providing insight into flows in porous media. The gut microbiota presents extensive genetic diversity shaped by its flow-dominated environment. Using a minimal model [2] incorporating flow, diffusion, and microbial growth that we extend to non-neutral mutations, we show how spatial structure and advection influence the fixation of beneficial mutants. This illustrates the interplay between flow, growth, and spatial heterogeneity in shaping microbial evolution. [1] Alexandre, A., Guérin, T. & Dean, D. S. Effective description of taylor dispersion in strongly corrugated channels. Physical Review E 111, 064124 (2025). [2] Labavić, D., Loverdo, C. & Bitbol, A.-F. Hydrodynamic flow and concentration gradients in the gut enhance neutral bacterial diversity. Proceedings of the National Academy of Sciences 119, e2108671119 (2022).

Lundi 15 Décembre 2025, 11:00 à IPHT, Salle Claude Itzykson, Bât. 774	IPHT-STA (Séminaire de Physique Statistique, CEA/Saclay)	physics
Patrick Valageas	From cosmology to statistical physics and condensed matter: Burgers and Gross-Pitaevskii equations
Abstract:	We will discuss some aspects of two dynamics, motivated from cosmology but which originally appeared in hydrodynamics, statistical physics and condensed matter, the Burgers and the Gross-Pitaevskii equations. In the first part, we will present a simple solvable case in 1D with Poisson initial conditions. In the second part, we will discuss the formation of dark matter vortices (as in superfluids).

Mercredi 17 Décembre 2025, 11:00 à LPENS, L378	FORUM-ENS (Forum de Physique Statistique @ ENS)	cond-mat.stat-mech
Zohar Nussinov ( Washington University in St. Louis )	TBA

Jeudi 18 Décembre 2025, 11:00 à IJCLAB, Bld. 210, Theory Seminar Room (114)	IJCLAB-PTH (Particle Theory Seminar of IJCLAB Orsay)	hep-ph
Lukas Allwicher ( DESY )	Cornering New Physics through precision measurements at FCC-ee
Abstract:	A future high-intensity e+e- collider running at the Z-pole, while not achieving high energies, offers great potential for BSM explorations through indirect effects. The prospected 6x10^12 Z bosons which would be produced on-shell would not only result in a leap in precision for traditional electroweak observables, but are an excellent heavy flavour factory as well. At the same time, experimental runs above the Z resonance up to the tt-threshold will offer different and complementary insights. We explore the implications of precision measurements at FCC-ee in the search for heavy new physics, both within an EFT approach and in explicit models.

Jeudi 18 Décembre 2025, 11:30 à IHP, Salle Yvette Cauchois, Bâtiment Perrin	RENC-THEO (Rencontres Théoriciennes)	hep-th
Markus Dierigl ( CERN )	TBA

Lundi 5 Janvier 2026, 11:00 à IPHT, Salle Claude Itzykson, Bât. 774	IPHT-MAT (Séminaire de matrices, cordes et géométries aléatoires)	physics
Rémy Mahfouf	La FK-percolation presque critique en milieu aléatoire
Abstract:	Nous étudions la percolation FK où les paramètres des arêtes sont choisis comme des variables aléatoires indépendantes dans le régime proche-critique. Nous montrons que si ces paramètres satisfont une condition naturelle de centrage autour du point critique, alors le modèle quenched présente typiquement un comportement critique à des échelles bien plus grandes que la longueur caractéristique déterministe. Plus précisément, dans une boîte de taille N, si le modèle homogène avec un paramètre d?arête déterministe p a un comportement critique dans le régime |p ? pc| ? W, alors le modèle quenched avec des paramètres d?arête aléatoires p qui satisfont typiquement |p ? pc| ? W^{1/3} a encore un comportement critique. Nous traitons également le cas particulier de la percolation de Bernoulli, où nous montrons que si l?on commence par échantillonner des paramètres d?arêtes aléatoires indépendants non dégénérés centrés autour de 1/2, puis une configuration de percolation sur ces arêtes, le modèle quenched  est presque sûrement critique à grande échelle. Basé sur un travail avec Emile Avérous, disponible sur arXiv 2509.08938.

Mercredi 7 Janvier 2026, 13:30 à DPT-PHYS-ENS, ConfIV (E244) - 24 rue Lhomond 75005 PARIS	COLLOQUIUM-ENS (Colloquium of the Physics Department of ENS)	physics
Yacoby	TBA
Abstract:	TBA

Jeudi 8 Janvier 2026, 16:00 à LPENS, L378	FORUM-ENS (Forum de Physique Statistique @ ENS)	cond-mat.stat-mech
Francesca Mignacco ( Princeton )	TBA

Vendredi 9 Janvier 2026, 12:00 à LPENS, L378	ENS-BIOPHYS (ENS Biophysics Seminar)	physics.bio-ph
Ananyo Maitra ( LPTM Cergy )	TBA

Lundi 12 Janvier 2026, 11:00 à IPHT, Salle Claude Itzykson, Bât. 774	IPHT-STA (Séminaire de Physique Statistique, CEA/Saclay)	physics
Sofia Flores	Vector Resonant Relaxation and Statistical Closure Theory. II. One-loop Closure
Abstract:	We use stellar dynamics as a testbed for statistical closure theory. We focus on the process of « Vector Resonant Relaxation, » a long-range, non-linear, and correlated relaxation mechanism that drives the reorientation of stellar orbital planes around a supermassive black hole. This process provides a natural setting to evaluate the predictive power of generic statistical closure schemes for dynamical correlation functions, in the fully non-linear and non-perturbative regime. We develop a numerical scheme that explicitly implements the seminal « Martin-Siggia-Rose » formalism at one-loop order via an iterative fixed-point approach, thereby improving upon the bare order from the « Direct Interaction Approximation. » Using this framework, we quantitatively validate the ability of the formalism to predict (i) the two-point two-time correlation function; (ii) the renormalised three-point interaction vertex; (iii) the three-point three-time correlation function. These predictions are compared to direct measurements from numerical simulations. We conclude by discussing the limitations of this approach and presenting possible future venues.

Mardi 13 Janvier 2026, 11:00 à IPHT, Amphi Claude Bloch, Bât. 774	IPHT-GEN (Séminaire général du SPhT)
Matthew Headrick ( Brandeis University )	TBA
Abstract:	TBA

Jeudi 15 Janvier 2026, 11:00 à LPTHE, bibliothèque du LPTHE, tour 13-14, 4eme étage	SEM-DARBOUX (Séminaire Darboux - physique théorique et mathématiques)	hep-th|math.AG
Jean Doucot ( Institute of Mathematics of the Romanian Academy )	TBA

Jeudi 15 Janvier 2026, 14:00 à LPTMC, Jussieu, LPTMC seminar room, towers 13-12, 5th floor, room 523	SEM-LPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée)	cond-mat
Evgeny Stepanov ( CPhT )	TBA

Lundi 19 Janvier 2026, 11:00 à IPHT, Salle Claude Itzykson, Bât. 774	IPHT-MAT (Séminaire de matrices, cordes et géométries aléatoires)	physics
Sergei Nechaev ( LPTMS (Paris-Saclay) )	What do Lifshitz tails, KPZ, and BKT have in common?
Abstract:	Abstract:  (i) We study the statistics of stretched two-dimensional random walks (Brownian bridges) in the vicinity of an impermeable disc using the optimal?fluctuation approach. We show that the transverse span of the walks away from the boundary scales with the Kardar?Parisi?Zhang (KPZ) exponent $1/3$. (ii) Using the analogy between the optimal fluctuation in this setting and that in the one-dimensional Balagurov?Vaks trapping problem, we propose a connection between KPZ-like statistics and Lifshitz tails arising in a deterministic large-deviation landscape. (iii) By interpreting the radial component of the random walk above the disc as diffusion in a conformally invariant $1/r^{2}$ potential, we recover the Efimov?BKT behavior of the associated renormalization-group flow. From a large-deviation perspective, we argue that the typical paths responsible for the BKT-like behavior belong to a sub-ensemble of stretched Brownian bridges driven into the large-deviation regime.

Jeudi 22 Janvier 2026, 14:00 à ESPCI, tba. ( Zoom link available at seminaires-lpem@espci.fr )	SEM-EXCEP (Seminaire exceptionnel)	cond-mat
Christoph Lange ( TU Dortmund University )	Frontiers in THz cavity QED: Deep-strong multi-mode coupling, subcycle nonlinearities, and diabatic switching
Abstract:	Dressing matter excitations with cavity photons can create novel, exotic quantum states. Ultrastrong coupling, where the ratio of vacuum Rabi frequency and carrier frequency of light, $\Omega_R/\omega_c$, approaches unity, has enabled vacuum-field modified transport, polaritonic chemistry, or strong mode squeezing and entanglement. Past investigations of this regime of cavity quantum electrodynamics (c-QED) focused on coupling of a single pair of light and matter modes, in equilibrium. Here, we discuss conceptually new extremes of c-QED. We demonstrate subcycle control of deep-strong coupling, where $\Omega_R/\omega_c$ is collapsed from 1.3 to zero within 5 $\%$ of the optical cycle duration, leading to characteristic trailing oscillations of the extinguished polariton states. Moreover, we investigate coherent subcycle nonlinearities of multiple cavity polaritons and observe dynamical mixing between otherwise orthogonal modes. Our most recent structures demonstrate extremely strong, multi-mode coupling of 20 matter resonances and multiple cavity modes over 6 optical octaves, boosting the number of virtual cavity photons beyond unity for the first time while achieving a record coupling strength of $\Omega_R/\omega_c$ = 3.19.