|
|
|
The SEMPARIS seminar webserver hosts annoucements of all seminars taking place in Paris area, in all topics of physics, mathematics and computer science. It allows registered users to receive a selection of announcements by email on a daily or weekly basis, and offers the possibility to archive PDF or Powerpoint files, making it available to the scientific community. [ More information ]
| Upcoming Seminars | [Next 30 ] | |
| [ scheduler view ] | ||
| Thursday 28 May 2026, 14:00 at
ESPCI,
Room Holweck, building C, 1st floor, 10 rue Vauquelin, ESPCI ( Please contact seminaires-lpem@espci.fr for the zoom link ) | SEM-EXCEP (Seminaire exceptionnel) | cond-mat |
|
|
|
|
| Attachments: |
| |
| Thursday 28 May 2026, 14:00 at IPHT, Salle Claude Itzykson, Bât. 774 | IPHT-MAT (Séminaire de matrices, cordes et géométries aléatoires) | physics |
|
|
|
|
| Abstract: | I will derive the analytic structure of the S-matrix for classical wave scattering on a Schwarzschild black hole in 4-dimensions. The argument relies on the analytic continuation of the gravitational potential, with the singularity behind the horizon playing a crucial role. We observe the emergence of Stokes phenomena leading to a surprising branch cut in the upper half plane, seemingly in tension with causality. I will discuss how this apparent paradox is solved and mention some bootstrap applications of these results. | |
| Thursday 28 May 2026, 14:00 at
IHES,
Amphithéâtre Léon Motchane ( Cours de l'IHES ) | MATH-IHES (TBA) | math |
|
|
|
|
| Abstract: | Nonlinear dispersive equations are partial differential equations to describe various wave phenomena where the primary effects are wave dispersion and nonlinear interactions. Even a single equation can have many different types of solutions depending on the initial data, such as scattering, blow-up, and solitons. The theme of this course is to classify global behavior of solutions in terms of the initial data. More precisely, the problem is to characterize the set of initial data corresponding to each type of solutions, together with the configuration of those sets, which also requires to analyze transient evolutions during intermediate time. Despite the recent progress for the soliton resolution conjecture, which classifies the asymptotic behavior, its link to the initial data is much less understood, mostly restricted in the data size, types of behavior, and by symmetry of the equation or the solutions. The lecture will focus on two model cases as attempts to extend it in two directions. The first is to extend the initial data set to more variety of solutions; we consider the nonlinear Klein-Gordon equation and initial data near superposition of the ground state solitons, which are unstable. It is natural to expect that the classification is also a superposition of the single soliton case, but the interactions among unstable modes of different growth rates and large radiation from collapsed solitons can possibly spoil such a simple picture, by energy transfer from the most unstable mode to the others. I will show how to preclude it by using elementary geometry of the Lorentz transform and space-time weighted energy tailored for radiations from multi-solitons. The second is to extend the equations to less symmetry; we consider the Zakharov system, which is a system of the Schrodinger and the wave equations with Hamiltonian and mass conservation, but without the Galilei or Lorentz invariance, nor the center of mass or energy. Such loss of structure poses serious difficulty especially in proving the rigidity that the minimal non-dispersive solutions must be the ground states. I will show how to overcome it, by combining virial-variational estimates and space-time estimates for non-radiative source terms. | |
| Thursday 28 May 2026, 17:00 at UFR-PHYS-SU, Amphi 25 Campus Pierre-et-Marie-Curie, Jussieu | CPMC (Colloquium Pierre et Marie Curie) | physics.bio-ph |
|
|
|
|
| Abstract: | TBA | |
| Friday 29 May 2026, 12:00 at LPENS, E012 (salle des éléments) | ENS-BIOPHYS (ENS Biophysics Seminar) | physics.bio-ph |
|
|
|
|
| Abstract: | Many biological patterns are thought to arise from Turing reaction–diffusion system, where morphogen interactions generate spatial organization, as seen in hair, feathers, and other skin appendages. However, not all patterns can be explained by chemical pre-patterning alone. In this talk, I will present the mammalian rhinarium (naked nose) as a case where patterning instead emerges from a mechanical self-organization process. Using volumetric imaging across development, we showed that polygonal grooves arise from constrained epidermal growth and buckling, with folds precisely aligned to an underlying network of stiff blood vessels. Numerical simulations reveal that these vessels act as rigid anchors that concentrate stress and set the characteristic length scale of the pattern. This supports the concept of mechanical positional information, whereby tissue mechanics locally guide an otherwise global self-organized process. Finally, analyses of genetical clones and pathological cases highlight the roles of stochasticity and altered material properties, emphasizing how mechanical and chemical frameworks provide complementary routes to biological pattern formation. | |
| Friday 29 May 2026, 14:00 at
IHES,
Amphithéâtre Léon Motchane ( Cours de l'IHES ) | MATH-IHES (TBA) | math |
|
|
|
|
| Abstract: | Nonlinear dispersive equations are partial differential equations to describe various wave phenomena where the primary effects are wave dispersion and nonlinear interactions. Even a single equation can have many different types of solutions depending on the initial data, such as scattering, blow-up, and solitons. The theme of this course is to classify global behavior of solutions in terms of the initial data. More precisely, the problem is to characterize the set of initial data corresponding to each type of solutions, together with the configuration of those sets, which also requires to analyze transient evolutions during intermediate time. Despite the recent progress for the soliton resolution conjecture, which classifies the asymptotic behavior, its link to the initial data is much less understood, mostly restricted in the data size, types of behavior, and by symmetry of the equation or the solutions. The lecture will focus on two model cases as attempts to extend it in two directions. The first is to extend the initial data set to more variety of solutions; we consider the nonlinear Klein-Gordon equation and initial data near superposition of the ground state solitons, which are unstable. It is natural to expect that the classification is also a superposition of the single soliton case, but the interactions among unstable modes of different growth rates and large radiation from collapsed solitons can possibly spoil such a simple picture, by energy transfer from the most unstable mode to the others. I will show how to preclude it by using elementary geometry of the Lorentz transform and space-time weighted energy tailored for radiations from multi-solitons. The second is to extend the equations to less symmetry; we consider the Zakharov system, which is a system of the Schrodinger and the wave equations with Hamiltonian and mass conservation, but without the Galilei or Lorentz invariance, nor the center of mass or energy. Such loss of structure poses serious difficulty especially in proving the rigidity that the minimal non-dispersive solutions must be the ground states. I will show how to overcome it, by combining virial-variational estimates and space-time estimates for non-radiative source terms. | |
| Monday 1 June 2026, 14:00 at LPNHE, Charpak | LPNHE (Séminaires du LPNHE) | physics |
|
|
|
|
| Abstract: | The standard model continues to provide an exceptionally successful description of particle interactions at the electroweak scale, while precision measurements at the LHC increasingly probe its structure in extreme kinematic regimes. This talk presents recent highlights of the CMS standard model physics program using the Run 2 and Run 3 datasets. The talk will discuss the growing role of precision object reconstruction, advanced analysis techniques, and new methods to interpret results, providing essential inputs to searches for physics beyond the standard model. | |
| Tuesday 2 June 2026, 11:00 at IPHT, Amphi Claude Bloch, Bât. 774 | IPHT-GEN (Séminaire général du SPhT) | |
|
|
|
|
| Abstract: | TBA | |
| Tuesday 2 June 2026, 14:00 at
LPENS,
Conf IV ( Note the unusual time and day! ) | LPENS-BQ (Balades Quantiques de le LPENS) | cond-mat.str-el |
|
|
|
|
| Abstract: | Topological quantum matter is characterized by invariants, abstract quantities that remain unchanged under perturbations. A paradigmatic example is the many-body Chern number, which quantizes the Hall conductivity of quantum Hall states [1]. However, these many-body invariants are intrinsically complex, motivating the search for simplified theoretical descriptions and experimentally accessible probes. In this talk, I present two complementary approaches to this challenge. First, I show that the many-body Chern number can be extracted from local, purely static ground-state current measurements [2]. This leads to explicit relations between measurable observables and a local many-body Chern marker, providing a practical route to detecting topological order at the level of individual lattice sites. These results are directly relevant to current and emerging quantum simulation platforms. Then, I investigate invariants formulated in terms of single-particle Green’s functions, addressing a fundamental tension in strongly-correlated quantum matter [3]. Indeed, while single-particle Green’s functions provide a rigorous framework for defining topological invariants, the low-energy physics of correlated topological phases is governed by collective excitations rather than single-particle degrees of freedom. I clarify the extent to which single-particle quantities encode the topological properties of fractional quantum Hall states [4]. [1] N. Goldman and T. Ozawa, Comptes Rendus. Physique, 25 289 (2024) [2] F. Palm, A. Impertro, M. Aidelsburger and N. Goldman, arXiv:2510.19742 [3] L. Peralta Gavensky, S. Sachdev and N. Goldman, Phys. Rev. Lett. 131, 236601 (2023) [4] A. Markov, A. Nikishin, N. Cooper, N. Goldman and L. Peralta Gavensky, arXiv:2603.17006 | |
| Wednesday 3 June 2026, 14:00 at
CDF,
Amphithéâtre Guillaume Budé (site Marcelin-Berthelot) ( 3e leçon ) | COURS (Cours) | hep-th |
|
|
|
|
| Abstract: | Gravitation carrollienne ($c \rightarrow 0$) | |
| Wednesday 3 June 2026, 16:00 at CDF, Amphithéâtre Guillaume Budé (site Marcelin-Berthelot) | SEM-EXCEP (Seminaire exceptionnel) | hep-th |
|
|
|
|
| Abstract: | Carrollian field theories are a class of non-Lorentzian field theories that have recently emerged as a candidate dual to flat space quantum gravity. In this talk, I will first review the connection between conformal Carrollian correlation functions and scattering amplitudes for massless particles from a purely algebraic perspective. I will then discuss the quantization of generic two-derivative electric and magnetic Carrollian theories, highlighting some of the subtleties involved in this process. As a concrete application and time permitting, I will discuss the quantization of a two-dimensional BMS$_3$-invariant field theory, which captures the boundary degrees of freedom of three-dimensional flat space gravity. | |
| Thursday 4 June 2026, 14:00 at LPTMC, campus Jussieu, couloir 12-13, 5ème étage, salle 5-23 | SEM-EXCEP (Seminaire exceptionnel) | cond-mat |
|
|
|
|
| Abstract: | The description of complex system by the concept of Replica Symmetry Breaking (RSB) was shaped by Giorgio Parisi in the 1980s to solve the mean-field spin glass, as honored by the Nobel price in 2021. RSB has been used to analyze systems such as spin glasses, neural networks, optimization problems, or machine learning. Unfortunaley, numerically these well know RSB-exhibiting problems are difficult since only exponential-time exact algorithms are available. Here two models are considered, directed polymers in random media and increasing subsequences, called Ulam's problem for the ground states, i.e. longest subsequences. The distributions of free energies or sequence lengths, respectively, exhibit complex large-deviation behavior, which can be numerically addressed by rare-event sampling algorithms. Furthermore, for both models it is possible to sample exactly in perfect thermal equilibrium with polynomial-time algorithms. This means, large system sizes are accessible, in contrast to, e.g., the case of spin glasses. The results from perfect sampling of some problem disorder ensembles indicate the presence of RSB with complex structured landscapes. Thus, the study of complex RSB behavior is conveniently accessible numerically for some models. Finally, for partially presorting random sequences, obe obtains a transition similar to a ferromagnet-spin glass transition. | |
| Thursday 4 June 2026, 14:00 at
ESPCI,
Room Holweck, building C, 1st floor, 10 rue Vauquelin, ESPCI ( Please contact seminaires-lpem@espci.fr for the zoom link ) | SEM-EXCEP (Seminaire exceptionnel) | cond-mat |
|
|
|
|
| Abstract: | We consider dressing of excitonic properties by strongly correlated electrons in gate-controlled twisted homo-bilayer heterostructures, as analyzed in recent experiments. The combined effect of the moiré potential and the Coulomb interaction supports the formation of different strongly correlated phases which depend on the filling, including charge-ordered metals or incompressible insulators at integer occupation. The coupling between excitons and electrons results in a splitting of the excitonic resonance into an attractive and a repulsive polaron peak. Analysing the properties of such exciton-polarons across the different phases of the system, we reveal a discontinuous evolution of the spectrum with the formation of a double-peak structure in the repulsive polaron branch. The double-peak structure emerges for non-integer fillings and it is controlled by the energy separation between the quasiparticle states close to the Fermi level and the high-energy excitations. Our results demonstrate that exciton-polarons carry a clear hallmark of the electronic correlations and, thus, provide a direct signature of the formation of correlation-driven insulators in gate-controlled heterostructures. [1] "Strongly correlated exciton-polarons in twisted homobilayer heterostructures" G.Mazza and A.Amaricci, Physical Review B letter, 106, L241104 (2022) [2] "Strongly correlated electrons and hybrid excitons in a moiré heterostructure", Y.Shimanzaki, Nature (London) 580, 472 (2020). | |
| Friday 5 June 2026, 13:00 at LPENS, Conf IV | ENS-BIOPHYS (ENS Biophysics Seminar) | physics.bio-ph |
|
|
|
|
| Friday 5 June 2026, 14:00 at
IHES,
Amphithéâtre Léon Motchane ( Séminaire d'Analyse ) | MATH-IHES (TBA) | math |
|
|
|
|
| Abstract: | Motivated by the phenomenon of duality for interacting particle systems we introduce two classes of Pfaffian kernels describing a number of Pfaffian point processes in the "bulk" and at the "edge". Using the probabilistic method due to Mark Kac, we prove two Szegő-type asymptotic expansion theorems for the corresponding Fredholm Pfaffians. The idea of the proof is to introduce an effective random walk with transition density determined by the Pfaffian kernel, express the logarithm of the Fredholm Pfaffian through expectations with respect to the random walk, and analyse the expectations using general results on random walks. We demonstrate the utility of the theorems by calculating asymptotics for the empty interval and non-crossing probabilities for a number of examples of Pfaffian point processes: coalescing/annihilating Brownian motions, massive coalescing Brownian motions, real zeros of Gaussian power series and Kac polynomials, and real eigenvalues for the real Ginibre ensemble. (Joint work with Will FitzGerald and Roger Tribe.) | |
| Monday 8 June 2026, 11:00 at IPHT, Salle Claude Itzykson, Bât. 774 | IPHT-MAT (Séminaire de matrices, cordes et géométries aléatoires) | physics |
|
|
|
|
| Abstract: | We study the long-time, large-distance asymptotic behaviour of dynamical two-point correlation functions of the Lieb?Liniger model in the limit of infinite repulsion (the one-dimensional impenetrable Bose gas). Starting with exact representations of correlation functions in terms of Fredholm determinants of an integrable integral operator, we perform the rigorous asymptotic analysis, using Riemann?Hilbert techniques. The integral operatordepends parametrically on time \(t\), distance \(x\) and on the filling fraction ? a function that characterizes the thermal or non-thermal equilibrium conditions. We consider a large class of non-thermal equilibrium conditions, extending previous results established for the thermal equilibrium case. The long-time and large-distance asymptotic behaviour is derived for two classes of filling fractions. These classes are characterized by the number of poles on the real axis (a generalization of Fermi points) that, together with the unique saddle point, contribute to the asymptotic expansion. For each class, we derive the long-time, large-distance symptotic behaviour as a series in \(x\)\(?1/2\) as \(x\) and \(t\) go to infinity for a fixed ratio \(x/t\). We provide explicit closed-form expressions for the leading and sub-leading terms, logarithmic corrections, and overall constants in terms of special functions and simple integrals. For the impenetrable Bose gas in thermal equilibrium, we verify the derived asymptotic expansions by comparing them with the existing results in the literature and with numerical data.This talk is based on joint work with Frank Göhmann, Karol K. Kozlowski, and Alexander Weiße. | |
| Monday 8 June 2026, 14:00 at
IHES,
Amphithéâtre Léon Motchane ( Séminaire Géométrie et groupes discrets ) | MATH-IHES (TBA) | math |
|
|
|
|
| Abstract: | Let S be a compact oriented surface with boundary, Γ its fundamental group, and G a simple algebraic group defined over Q such that the symmetric space associated to G(R) is Hermitian of tube type. Given a real closed field F and a canonical presentation of Γ, we define for a representation of Γ in G(F) an invariant taking values in an ordered abelian group A(F), called the refined Toledo invariant, as it generalizes the Toledo number in the case F = R. The group A(F) has a geometric interpretation as the group of signed areas for polygons in the Hilbert geometry associated to the upper half plane over F. The goal of the talk is to describe the construction of this invariant and to explain how it solves the problem of characterizing points in the real spectrum compactification of the space of maximal representations of Γ into G(R). | |
| Monday 8 June 2026, 14:00 at LPNHE, Salle des Seminaires | LPNHE (Séminaires du LPNHE) | physics |
|
|
|
|
| Abstract: | What if we could make predictions for experimental measurements at the Large Hadron Collider based entirely on first-principles theoretical calculations? While this dream is hopelessly out of reach, we do have a growing catalog of precision calculations in quantum chromodynamics (QCD) as a well as increasingly accurate Monte Carlo generators. In this talk, I show how to leverage ideas from information theory and machine learning to merge these disparate QCD predictions into a unified theoretical prediction with associated uncertainties. Our strategy highlights the importance of logarithmic moments, which have not been previously studied in the QCD literature, either experimentally or theoretically. | |
| Monday 8 June 2026, 16:00 at
IHES,
Amphithéâtre Léon Motchane ( Séminaire Géométrie et groupes discrets ) | MATH-IHES (TBA) | math |
|
|
|
|
| Abstract: | Conjugacy classes in rank n affine Coxeter groups have a beautiful and simple geometric description in terms of their natural action on (n-1)-dimensional vector spaces. Moreover, one can locate the conjugating elements and centralizers in the vector space as well. These results allow to characterize the growth of the conjugator length function by geometric investigations. | |
| Tuesday 9 June 2026, 10:45 at 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 |
|
|
|
|
| Abstract: | In many disease, proteins aggregate into fibers. Why? One could think of molecular reasons, but here we try something more general. We propose that when particles with complex shapes aggregate, geometrical frustration builds up and fibers generically appear. Such a rule could be very useful in designing artificial self-assembling systems. | |
| Thursday 11 June 2026, 11:00 at
IHES,
Amphithéâtre Léon Motchane ( Séminaire de Géométrie Arithmétique ) | MATH-IHES (TBA) | math |
|
|
|
|
| Abstract: | A longstanding question in the theory of Shimura varieties concerns their perfectoidness at infinite level — a property that would reveal deep connections between étale and coherent cohomology. In this talk, we establish a criterion for perfectoidness via Sen theory, building on a new development of p-adic Hodge theory for general valuation fields that extends Tate’s foundational work on local fields. We further provide a conceptual explanation, based on the p-adic Simpson correspondence after Abbes-Gros, Liu-Zhu and Tsuji, for why Shimura varieties satisfy this criterion, at least in the case of modular curves. For general Shimura varieties, it follows through additional technical arguments due to Pan and Rodríguez Camargo. This yields the “pointwise perfectoidness” of Shimura varieties at infinite level, which suffices to establish the desired connection between different cohomologies. As an application, we show that integral completed cohomology groups vanish in higher degrees, thereby confirming a conjecture of Calegari and Emerton for arbitrary Shimura varieties. | |
| Thursday 11 June 2026, 11:00 at LPTHE, bibliothèque du LPTHE, tour 13-14, 4eme étage | SEM-DARBOUX (Séminaire Darboux - physique théorique et mathématiques) | hep-th |
|
|
|
|
| Thursday 11 June 2026, 14:00 at
ESPCI,
Room Boreau, building C, 2nd floor, 10 rue Vauquelin, ESPCI ( Please contact seminaires-lpem@espci.fr for the zoom link ) | SEM-EXCEP (Seminaire exceptionnel) | cond-mat |
|
|
|
|
| Abstract: | see attached pdf file. | |
| Attachments: |
| |
| Friday 12 June 2026, 13:00 at LPENS, E012 (salle des éléments) | ENS-BIOPHYS (ENS Biophysics Seminar) | physics.bio-ph |
|
|
|
|
| Friday 12 June 2026, 14:00 at LPTHE, library | LPTHE-PPH (Particle Physics at LPTHE) | hep-ph |
|
|
|
|
| Tuesday 16 June 2026, 11:30 at
IHES,
Centre de conférences Marilyn et James Simons ( Séminaire Laurent Schwartz EDP et applications ) | MATH-IHES (TBA) | math |
|
|
|
|
| Tuesday 16 June 2026, 13:30 at
IHES,
Centre de conférences Marilyn et James Simons ( Séminaire Laurent Schwartz - EDP et applications ) | MATH-IHES (TBA) | math |
|
|
|
|
| Tuesday 16 June 2026, 14:00 at CPHT, Salle de Conférence Jean Lascoux | SEM-CPHT (Séminaire du CPHT) | hep-th |
|
|
|
|
| Abstract: | TBA | |
| Tuesday 16 June 2026, 15:00 at
IHES,
Centre de conférences Marilyn et James Simons ( Séminaire Laurent Schwartz - EDP et applications ) | MATH-IHES (TBA) | math |
|
|
|
|
| Wednesday 17 June 2026, 11:00 at LPENS, E239 (Bibliothèque de physique théorique) | FORUM-ENS (Forum de Physique Statistique @ ENS) | cond-mat.stat-mech |
|
|
|
|
|
PDF Poster |
RSS Thread |
ICal Format
]
| [ Bulletin Board ] [ Subscription ] [ Archive] [ Help ] [ ] | [ Version francaise ] |
