David Ruelle a apporté nombre de contributions majeures et durables dans plusieurs domaines de la physique : théorie quantique des champs axiomatique (théorie de Haag-Ruelle) ; mécanique statistique de l’équilibre (équations de Dobrushin-Lanford-Ruelle) ; théorie de la turbulence (concept d’ « attracteur étrange » de Ruelle-Takens) ; théorie des systèmes dynamiques et du chaos (opérateurs de transfert, mesures SRB (Sinaï, Ruelle, Bowen)) ; mécanique statistique du non-équilibre. Il est devenu professeur permanent à l’IHÉS en 1964 (professeur honoraire depuis 2000).

Organisé par : Thibault Damour et Jean-Pierre Eckmann

Conférenciers :

15h00-16h00
Viviane BALADI (CNRS-IMJ-PRG) 
Spectres d'opérateurs de transfert et billards de Sinai

Depuis une douzaine d'années, on sait contrôler le spectre d'un opérateur de transfert agissant sur un espace de distributions anisotropes. Ceci a permis de simplifier les preuves de résultats obtenus par d'autre méthodes (partitions de Markov, tours de Lai-Sang Young), mais aussi d'obtenir de nouveaux résultats qui avaient résisté aux autres approches.

Avec Mark Demers et Carlangelo Liverani nous avons ainsi récemment montré que les flots billards de Sinai mélangent exponentiellement vite. L'exposition de ce résultat sera ainsi l'occasion de donner un rapide panorama du sujet.

16h30-17h30
Hans Henrik RUGH (Université Paris-Sud Orsay)
The Milnor-Thurston determinant and the Ruelle transfer operator

The topological entropy htop of a continuous piecewise monotone interval map measures the exponential growth in the number of monotonicity intervals for iterates of the map. Milnor and Thurston showed that exp(-htop) is the smallest zero of an analytic function, now coined the Milnor-Thurston determinant, that keeps track of relative positions of forward orbits of critical points. On the other hand exp(htop) equals the spectral radius of a Ruelle transfer operator L, associated with the map. Iterates of L keep track of inverse orbits of the map. For no obvious reason, a Fredholm determinant for the transfer operator has not only the same leading zero as the M-T determinant but all peripheral (those lying in the unit disk) zeros are the same.

In the talk I will show that on a suitable function space, the dual of the Ruelle transfer operator has a regularized determinant, identical to the Milnor-Thurston determinant, hereby providing a natural explanation for the above puzzle.

17h45 : Reception

 

The aim of this workshop is to bring together mathematicians and computer scientists around some talks on recent results from statistics, machine learning and more generally data science research. Various topics in machine learning, optimization, deep learning, optimal transport, inverse problems, statistics and problems of scientific reproducibility will be presented.

Registration is free and open to January 20, 2020.

Organised by: Alexandre Gramfort (INRIA) and Thanh Mai Pham NGOC (LMO Orsay)

Invited speakers:

Sarah Cohen-Boulakia (LRI, Paris-Sud)
Victor-Emmanuel Brunel (ENSAE/CREST)
Steve Oudot (INRIA)
Charles Soussen (CentraleSupélec)
Gilles Blanchard (IHES)
Quentin Merigot (Paris-Sud)

The second joint workshop between Nokia Bell Labs and the Institut des Hautes Études Scientifiques will take place on the next November 25.

To celebrate this event, we will have four excellent conferences given by experts in their field:

Stéphane Mallat (Collège de France) will adress Multiscale Models for Image Classification and Physics with Deep Networks ;

Jakob Hoydis (Nokia Bell Labs France/Paris-Saclay) will explain Recent Progress in End-to-End Learning for the Physical Layer ; 

Michael Douglas (Simons Center in Geometry and Physics – SUNY) will think about How will we do mathematics in 2030? ;

Philippe Jacquet (Inria – Nokia Bell Labs) will compare AI vs Information theory and learnability.

This second joint workshop marks Nokia Bell Labs donation to the Institut des Hautes Études Scientifiques in 2017. Nokia Bell Labs is one of the largest and oldest private research laboratories in the world and perhaps the only one to offer a continuous flow of impressive scientific discoveries and theoretical contributions over the past century.

Organisers: Philippe JACQUET (Nokia – FR/Paris-Saclay), Emmanuel ULLMO (IHES)

The Ising model is one of the most classical models of statistical physics and has been a testing ground for mathematicians and physicists for a century. On the occasion of its 100th anniversary, postponed from 2020 to 2022, the Institut des Hautes Études Scientifiques (IHES) organises a special conference that will take place 30 May to 3 June 2022, with talks from various fields involved in the study of the model.

This event should serve as a platform between mathematicians and physicists working in the domain. 

This conference is organised by: Hugo Duminil-Copin (IHES), Slava Rychkov (IHES) and Béatrice de Tilière (Cérémade, Univ. Paris-Dauphine)

 

© Clément Hongler (EPFL)

 

List of speakers and round-table participants:

Michael AIZENMAN, Princeton University (Speaker)
Roland BAUERSCHMIDT, University of Cambridge (Speaker)
Edouard BRÉZIN, ENS Paris (Round-table)
Michele CASELLE, Università di Torino (Speaker)
Loren COQUILLE, Université Grenoble-Alpes (Speaker)
Victor DOTSENKO, LPTMC Jussieu (Speaker)
Daniel FISHER, Stanford University (Speaker)
Jürg FRÖHLICH, ETH Zürich (Round-table)
Alessandro GIULIANI, Università di Roma 3 (Speaker)
Rafael GREENBLATT, Universita’ degli Studi Roma Tre (Speaker)
Geoffrey GRIMMETT, University of Cambridge (Round-table)
Clément HONGLER, EPFL (Speaker)
Arthur JAFFE, Harvard University (Round-table)
Rick KENYON, Yale University (Speaker)
Joel LEBOWITZ, Rutgers University (Round-table)
Eyal LUBETZKY, Courant Institute, NYU (Speaker)
Giuseppe MUSSARDO, SISSA Trieste (Speaker)
Eveliina PELTOLA, HCM University of Bonn (Speaker)
Ara SEDRAKYAN, Yerevan Physics Institute (Speaker)
Stanislav SMIRNOV, University of Geneva (Speaker)
Tom SPENCER, IAS (Round-table)
Vincent TASSION, ETH Zürich (Speaker)
Fabio TONINELLI, Technical University of Vienna (Speaker)
Yvan VELENIK, Université de Genève (Speaker)
Alessandro VICHI, Università di Pisa (Speaker)
Wendelin WERNER, ETH Zürich (Speaker)
Jean ZINN-JUSTIN, CEA Saclay (Speaker)

 A conference in honor of Samson Shatashvili’s 60th birthday

The interactions of Mathematics and Physics have greatly intensified during the last three decades, and it led to a number of very significant breakthroughs in Mathematics. Among other things, these breakthroughs include new invariants of 3 and 4-dimensional manifolds, the discovery of mirror symmetry in Algebraic Geometry, and the theory of deformation quantization. This progress became possible due to close interactions between Mathematics and theoretical Physics and due to the dialogue between mathematicians and physicists working on similar problems but using very different methods.

The conference will touch upon two important aspects of interaction between Mathematics and Quantum Field Theory: Quantum Integrability and Anomalies. It will honour Professor Samson Shatashvili on the occasion of his 60th birthday.

Professor Samson Shatashvili made deep contributions in the theory of anomalies and in quantum integrability. In particular, in collaboration with L. Faddeev he discovered the interpretation of gauge theory anomalies in terms of abelian extensions of gauge groups on manifolds of odd dimension. In the theory of quantum integrability, together with a number of collaborators he discovered a deep link between Bethe equations and supersymmetric quantum gauge theory. Professor Shatashvili (of the Trinity College, Dublin and the Simons Center for Geometry and Physics, Stony Brook) served as a Louis Michel Chair and then as an Israel Gelfand Chair at IHES for many years. He contributed in a significant way in the development of ideas and in the unique research atmosphere of IHES.

Organisers: Anton Alekseev (Université de Genève) & Maxim Kontsevich (IHES)

Invited speakers include:

Costas Bachas (ENS-Paris)
Jean-Michel Bismut (Université Paris-Sud Orsay)
Gregory Gabadadze (New York University)
Sergei Gukov (Caltech)
Simeon Hellerman (IPMU)
Chris Hull (Imperial College London)
Vladimir Kazakov (ENS-Paris)
Zohar Komargodski (SCGP)
Vladimir Korepin (Stony Brook University)
Manuela Kulaxizi (Trinity College Dublin)
Sergei Lukyanov (Rutgers University)
Ruben Minasian (IPhT – CEA Saclay)
Vasily Pestun (IHES)
Alexey Rosly (ITEP, Skoltech, HSE, IITP, Moscow)
Sinead Ryan (Trinity College Dublin)
Ivo Sachs (LMU Munich)
Nana Shatashvili (Tbilisi State University, Georgia)
Fedor Smirnov (LPTHE Sorbonne-Université)
Leon Takhtajan (Stony Brook University)
Anne Taormina (Durham University)
Cumrum Vafa (Harvard University)
Pierre Vanhove (IPhT & CEA Saclay)
Erik Verlinde (Universiteit van Amsterdam)
Alexander Zamolodchikov (Stony Brook University)

 

Avec le soutien du LHM

Combinatorics and Arithmetic for Physics: special days

The meeting’s focus is on questions of discrete mathematics and number theory with an emphasis on computability. Problems are drawn mainly from theoretical physics (renormalisation, combinatorial physics, geometry) or related to its models.

Computation, based on combinatorial structures (graphs,trees, words, automata, semirings, bases) or classic structures (operators, Hopf algebras, evolution equations, special functions, categories) are good candidates for computer-based implementation and experimentation.

Organised by : Gérard H.E. Duchamp, Maxim Kontsevich, Gleb Koshevoy et Hoang Ngoc Minh

Invited speakers :

Nicolas Behr (Université de Paris, IRIF)
Marc Bellon (LPThE-Sorbonne-Univ., Paris and CNRS)
Pierre Cartier (IHES)
Bérénice Delcroix-Oger (Université de Paris, IRIF)
Gérard Duchamp (IHP and LIPN, Univ. Paris XIII)
Thomas Fernique (CNRS and LIPN, Univ. Paris XIII)
Stéphane Gaubert (INRIA and CMAP, École Polytechnique)
Dima Grigoryev (CNRS Painlevé Lab, Univ. Lille)
Dmitry Gurevich (Valenciennes Univ., France)
Richard Kerner (LPTMC, Sorbonne-Univ., Paris)
Maxim Kontsevich (IHES)
Gleb Koshevoy (ISCP, Moscow)
Annie Lemarchand (LPTMC, Sorbonne-Univ., Paris)
Léon Masurel (LPTMC, Sorbonne-Univ., Paris)
Vincel Hoang Ngoc Minh (Univ. Lille and LIPN, Univ. Paris XIII)
Gabriel Morgado (LPTMC, Sorbonne-Univ., Paris)
Frédéric Patras (LJAD, Univ. Côte d’Azur and CNRS)
Karol A. Penson (LPTMC, Sorbonne-Univ., Paris)
Vincent Rivasseau (LPT, Univ. Paris-Sud, Orsay)
Alan Sokal (University College London and New York University)
Pierre Vanhove (IPhT CEA/Saclay, HSE)

      

—————————————– IMPORTANT INFORMATION ——————————————

Due to the evolution of the health situation related to the Coronavirus epidemic, the conference will finally be totally on line. The Zoom link will be sent in the confirmation mail.

———————————————————————————————————————-

Algebraic Structures in Perturbative Quantum Field Theory
A conference in honour of Dirk Kreimer’s 60th birthday

On the occasion of Dirk Kreimer’s birthday, there will be a special issue of SIGMA on « Algebraic Structures in Perturbative Quantum Field Theory ».

Perturbative quantum field theory is essential for precision calculations of observables measured in experiments like the LHC, and therefore it is crucial for our understanding of the physics of the universe. At the same time, it is an extremely rich source of connections to a wide range of active research areas in mathematics. For example, Feynman integrals give rise to interesting motives and periods in algebraic geometry, their renormalization rests on combinatorial Hopf algebras underlying Feynman graphs, and further relations to noncommutative geometry and the moduli space of tropical curves and outer space have also been discovered.

This growing program keeps expanding in both breadth and depth, and exciting young researchers are entering the field. Now is an opportune time to bring together scientists working on all related aspects, to review old and new connections and to advance the state of the art. Lectures by established scientists will be accompanied by talks from young researchers, including a session dedicated to present and discuss open problems.

Close collaborations between mathematicians and physicists have been absolutely key for this kind of research, and many were initiated by Dirk Kreimer. Throughout his career, he made substantial contributions across these topics and led students and collaborators to the profound mathematical structures in perturbative quantum field theory that we are aware of today. Dirk Kreimer spent a particularly productive time at the IHES, and it is an honour that this workshop takes place in its inspiring and interdisciplinary environment.

Organisers: Erik PANZER (University of Oxford) & Karen YEATS (University of Waterloo)

Invited speakers include:

Ali Assem Mahmoud, University of Waterloo
Marc Bellon, LPTHE (Sorbonne Université)
Marko Berghoff, Humboldt-Universität
Spencer Bloch, University of Chicago
Johannes Blümlein, DESY Zeuthen
Michael Borinsky, Nikhef
David Broadhurst, The Open University
Francis Brown, University of Oxford
Yvain Bruned, University of Edinburgh
Alain Connes, IHES & Collège de France
Andrei Davydychev, Moscow State University
Gérald Dunne, University of Connecticut
Kurusch Ebrahimi-Fard, NTNU Trondheim
Loïc Foissy, Université du Littoral Côte d’Opale
Hadleigh Frost, University of Oxford
John Gracey, University of Liverpool
Martin Hairer, Imperial College London
Ralph Kaufmann, Purdue University
Thomas Krajewski, CPT Aix-Marseille
Dominique Manchon, CNRS & Université Clermont-Auvergne
Lukas NABERGALL, University of Waterloo
Sylvie Paycha, Institut für Mathematik Potsdam
Oliver Schnetz, FAU Erlangen-Nürnberg
Christian Schubert, Universidad Michoacana de San Nicolas de Hidalgo
Matt Szczesny, Boston University
Walter van Suijlekom, Radboud Universiteit Nijmegen
Karen Vogtmann, University of Warwick
Raimar Wulkenhaar, Westfälische Wilhelms-Universität Münster

 

Organized with the support of:

—————————————– IMPORTANT INFORMATION ——————————————

Due to the evolution of the health situation related to the Coronavirus epidemic, the conference will finally be totally on line. The Zoom link will be sent in the confirmation mail.

———————————————————————————————————————-

 

Combinatorics and Arithmetic for Physics: special days

The meeting’s focus is on questions of discrete mathematics and number theory with an emphasis on computability. Problems are drawn mainly from theoretical physics (renormalisation, combinatorial physics, geometry, evolution equations, noncommutative differential equations) or related to its models, but not only.

Computation, based on combinatorial structures (graphs,trees, words, automata, semirings, bases) or classic structures (operators, Hopf algebras, evolution equations, special functions, categories) are good candidates for computer-based implementation and experimentation. »

Organised by : Gérard H.E. Duchamp, Maxim Kontsevich, Gleb Koshevoy et Hoang Ngoc Minh

Updated information (as the Book of Abstracts) can be found there
https://www-lipn.univ-paris13.fr/~duchamp/Conferences/CAP7_2020.html

The aim of this workshop is to bring together mathematicians and computer scientists around some talks on recent results in statistics and machine learning. Various topics will be presented, among which sequential learning, aggregation of estimators, Hidden Markov models, network inference and optimization for machine learning.

Organised by : Sylvain ARLOT

Invited speakers :

Pierre Alquier (ENSAE)
Stéphane Gaiffas (Ecole Polytechnique)
Claire Lacour (Université Paris-Sud)
Odalric-Ambrym Maillard (INRIA – Université Paris-Sud)
Yann Ollivier (CNRS – Université Paris-Sud)
Joseph Salmon (LTCI, CNRS, Télécom ParisTech)

 

 

COMPUTATIONAL AND STATISTICAL TRADE-OFFS IN LEARNING

Organized by: Sylvain Arlot (Université Paris-Sud, Paris-Saclay), Francis Bach (INRIA Paris), Alain Celisse (Université de Lille 1)

This workshop focuses on the computational and statistical trade-offs arising in various domains (optimization, statistical/machine learning).
This is a challenging question since it amounts to optimize the performance under limited computational resources, which is crucial in the large-scale data context.
One main goal is to identify important ideas independently developed in some communities that could benefit the others.

Speakers :

Pierre Alquier (ENSAE, Paris-Saclay)
Alexandre d'Aspremont (D.I., CNRS/ENS Paris)
Quentin Berthet (DPMMS, Cambridge Univ., UK)
Alain Celisse (Université de Lille 1)
Rémi Gribonval (INRIA, Rennes)
Emilie Kaufmann (CNRS, Lille)
Vianney Perchet (CREST, ENSAE Paris-Saclay)
Garvesh Raskutti (Wisconsin Institute for Discovery, Madison, USA)
Ohad Shamir (Weizmann Institute, Rehovot, Israel)
Silvia Villa (Istituto Italiano di Tecnologia, Genova & MIT, Cambridge, USA)

 

As part of the IHES-Huawei partnership, this one-day workshop is organised by the Huawei's Mathematical and Algorithmic Sciences Lab jointly with IHÉS and aims at creating scientific exchanges around mathematical topics that are essential for the development and innovation of the ICT.

 

Arithmetic and Algebraic Geometry:

A conference in honor of Ofer Gabber on the occasion of his 60th birthday

List of speakers includes:

     Y. André (CNRS & IMJ-PRG),
     A. Beilinson (University of Chicago),
     B. Bhatt (University of Michigan),
     B. Conrad (Stanford),
     G. Faltings (MPIM),
     D. Gaitsgory (Harvard),
     K. Kato (University of Chicago),
     N. Katz (Princeton),
     M. Kisin (Harvard),
     G. Laumon (Université Paris-Sud),
     G. Lusztig (MIT),
     M. Olsson (UC Berkeley),
     F. Orgogozo (CNRS & École polytechnique),
     L. Ramero (Université de Lille I),
     T. Saito (University of Tokyo),
     P. Scholze (Universität Bonn),
     A. Shiho (University of Tokyo),
     Y. Varshavsky (Hebrew University of Jerusalem),
     A. Vasiu (Binghamton University),
     G. Williamson (University of Sydney),
     W. Zheng (Morningside Center of Mathematics)

Organising Committee:

     A. Abbes (CNRS & IHÉS),
     S. Bloch (University of Chicago),
     L. Illusie (Université Paris-Sud),
     B. Mazur (Harvard)

Organized in partnership with