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, 10:00 à IHP, Amphi Darboux	RENC-THEO (Rencontres Théoriciennes)	hep-th
Markus Dierigl ( CERN )	The importance of being discrete
Abstract:	In this talk I will highlight the importance of discrete data in gauge and gravitational theories. In particular I will describe the classification of deformation classes of spacetime manifolds equipped with these discrete structures (such as discrete gauge fields). These are important for the determination of (topological) global symmetries and anomalies of the underlying theory. In case of quantum gravity theories we expect all global symmetries to be absent and an inclusion of certain defects is required. Finally, I will also describe a strategy to bound allowed discrete gauge symmetries in theories of quantum gravity.

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, Amphi Darboux	RENC-THEO (Rencontres Théoriciennes)	hep-th
Oscar Varela ( utah state university, ift madrid )	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, 10:00 à IHP, Room Yvette Cauchois (Perrin building)	RENC-THEO (Rencontres Théoriciennes)	hep-th
Romuald Janik ( Jagiellonian U. )	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

Vendredi 16 Janvier 2026, 14:00 à LPTHE, Library ( In the library and via Zoom: https://cern.zoom.us/j/63031219326? pwd=STlDY2l0UTZOTWd3Ty8zaWVQSzNTdz09 )	LPTHE-PPH (Particle Physics at LPTHE)	hep-ph
Nicolas Grimbaum-Yamamoto ( ULB Bruxelles )	Primordial high energy neutrinos
Abstract:	In this talk, I will discuss the prospects for detecting high energy neutrinos produced before recombination by the decay or annihilation of early Universe relics. The focus is on identifying sharp spectral features, influenced by cosmological redshift and radiative effects, and determining when these features remain intact or are erased by interactions on the way to the detector. I will outline the viable ranges of particle mass, lifetime, and abundance consistent with cosmological and observational constraints, and identify which regions of parameter space remain promising for future searches. I will also briefly present our Monte Carlo treatment of spectral distortions of the primordial high energy neutrino spectrum induced by scattering on the cosmic neutrino background.

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.

Mercredi 21 Janvier 2026, 11:00 à LKB, Charpak	SEM-LKB (Séminaire du Laboratoire Kastler Brossel)	quant-ph
Jonathan Pritchard ( University of Strathclyde )	Quantum computation and optimisation using neutral atom arrays
Abstract:	Neutral atoms have emerged as a powerful and scalable platform for quantum computing, offering the ability to generate large numbers of identical and high quality qubits in reconfigurable arrays. By coupling atom to highly excited Rydberg states with strong, long-range dipole-dipole interactions it is possible to perform high-fidelity two and multi-qubit gate operations, or to natively implement classical graph optimisation problems, highlighting the versatility for performing both analogue and digital quantum computing. In this talk we will present work at Strathclyde focused on developing large-scale system for quantum computing and optimisation, including demonstration of high fidelity single qubit gate operations on up to 225 qubits with errors below the threshold for fault tolerance using a non-destructive readout technique, as well as initial results from performing weighted graph optimisation using programmable local light-shifts across the atomy array. This provides a route to embedding a wider class of problems including quadratic unconstrained binary optimisation (QuBO) and integer factorisation, and extension to native implementations of graph colouring. Alongside progress towards large-scale analogue optimisation, we will present a new cryogenic dual-species setup targeting fault-tolerant digital computation using quantum error-correction. This approach offers suppression of mid-circuit readout errors due to use of atoms of different species, and will provide a versatile test-bed for prototyping and benchmarking performance and scalability of recently proposed quantum low-density parity check codes.

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.

Vendredi 23 Janvier 2026, 12:00 à LPENS, L378	ENS-BIOPHYS (ENS Biophysics Seminar)	physics.bio-ph
Jéremie Guedj ( IAME, INSERM )	TBA

Mercredi 28 Janvier 2026, 11:00 à LPENS, L378	FORUM-ENS (Forum de Physique Statistique @ ENS)	cond-mat.stat-mech
Mikhail Feigel'man ( Google )	TBA

Mercredi 28 Janvier 2026, 13:30 à IHP, Amphi Choquet-Bruhat (batiment Perrin)	SEED (Seed Seminar of Mathematics and Physics)	math-ph
Kickoff Winter Trimester	TBA

Mercredi 28 Janvier 2026, 15:00 à IHP, Amphi Choquet-Bruhat (batiment Perrin)	SEED (Seed Seminar of Mathematics and Physics)	math-ph
Kickoff Winter Trimester	TBA

Mercredi 28 Janvier 2026, 16:30 à IHP, Amphi Choquet-Bruhat (batiment Perrin)	SEED (Seed Seminar of Mathematics and Physics)	math-ph
Kickoff Winter Trimester	TBA

Jeudi 29 Janvier 2026, 14:00 à ESPCI, tba. ( Zoom link available at seminaires-lpem@espci.fr )	SEM-EXCEP (Seminaire exceptionnel)	cond-mat
Mikhail Feigel'man ( Univ. Grenoble Alpes, France and CENN Nanocenter, Slovenia )	Tba.
Abstract:	tba.

Mardi 3 Fevrier 2026, 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
Larré ( LPTMS )	TBA

Mercredi 4 Fevrier 2026, 11:00 à LPENS, L378	FORUM-ENS (Forum de Physique Statistique @ ENS)	cond-mat.stat-mech
Bastien Lapierre ( LPENS/IPM )	TBA

Mardi 10 Fevrier 2026, 11:00 à IPHT, Amphi Claude Bloch, Bât. 774	IPHT-GEN (Séminaire général du SPhT)
Miguel Montero ( IFT Madrid )	TBA
Abstract:	TBA

Jeudi 12 Fevrier 2026, 11:00 à LPTHE, bibliothèque du LPTHE, tour 13-14, 4eme étage	SEM-DARBOUX (Séminaire Darboux - physique théorique et mathématiques)	gr-qc|hep-th
Jacques Smulevici ( IMJ-PRG )	TBA

Mercredi 18 Fevrier 2026, 11:00 à LPENS, L378	FORUM-ENS (Forum de Physique Statistique @ ENS)	cond-mat.stat-mech
Max Mcginley	TBA

Mercredi 18 Fevrier 2026, 11:00 à LKB, Charpak	SEM-LKB (Séminaire du Laboratoire Kastler Brossel)	quant-ph
Tanja Mehlstäubler ( Physikalisch-Technische Bundesanstalt & Leibniz Universität Hannover Germany )	Precision Spectroscopy in Ion Coulomb Crystals and Search for New Physics
Abstract:	Trapped and laser-cooled ions allow for a high degree of control of atomic quantum systems. They are the basis for modern atomic clocks, quantum computers and quantum simulators. In our research we use ion Coulomb crystals, i.e. many-body systems with complex dynamics, for precision spectroscopy. This paves the way to novel optical ion clocks with ultra-high stability and accuracy for applications such as relativistic geodesy and quantum simulators in which complex dynamics become accessible with atomic resolution. On the other hand, the high precision obtained in the spectroscopy of trapped cold ions enables sensitive tests of the Standard Model and the search for new physics, such as a stringent test of Local Lorentz Invariance. The long-lived F-state of the Yb+-ion has a high sensitivity to both relativistic and nuclear effects. We also use isotope-shift spectroscopy as a sensitive probe for nuclear structure and fifth forces mediated by a new boson that couples to electrons and neutrons. Deviations from a linear relation in the King-plot analysis can indicate new physics or higher-order SM effects. This powerful technique revealed large King-plot nonlinearities in Yb. In my talk I will discuss the current state of the art regarding the search for new physics and the investigation of nuclear structure.

Jeudi 19 Fevrier 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
Nicolas Pavloff ( LPTMS )	TBA
Abstract:	TBA