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Seminar at the
Laboratoire Jacques-Louis Lions
Université Pierre et Marie Curie, Paris
Organizers
Philippe G. LeFloch (Paris)
Jacques Smulevici (Orsay)
Jérémie Szeftel (Paris)
This Fall: October 10, November 21, and December 12, 2016
Monday October 10, 2016
room 15/25-104
14h Peter Hintz (Berkeley)
Nonlinear stability of Kerr-de Sitter black holes
Abstract. In joint work with András Vasy, we recently established the stability of the Kerr-de Sitter family of black holes as solutions of the initial value problem for the Einstein vacuum equations with positive cosmological constant, for small angular momenta but without any symmetry assumptions on the initial data. I will explain the general framework which enables us to deal systematically with the diffeomorphism invariance of Einstein’s equations, and thus how our solution scheme finds a suitable (wave map type) gauge within a carefully chosen finite-dimensional family of gauges; I will also address the issue of finding the mass and the angular momentum of the final black hole.
15h30 Stefan Czimek (Paris)
An extension procedure for the constraint equations
Abstract. In this talk we present a new extension procedure for the maximal constraint equations of general relativity, motivated by applications to the Cauchy problem. Given a small solution on the unit ball, we can extend it to an asymptotically flat global solution. The main features are that our extension procedure does not need a gluing region, preserves regularity and works in weak regularity. For the proof, we use new methods to solve the prescribed divergence equation for the second fundamental form and the prescribed scalar curvature equation for the metric. We use the under-determinedness of the constraint equations to conserve regularity.
Monday November 21, 2016
room 15/16-413
14h The-Cang Nguyen (Paris)
Progress and recent results for the conformal equations
Abstract. The presentation will be divided into two parts. First, I will introduce the conformal equations and present recent results for these equations as well as questions arising naturally. In a second part, I will talk about the “half-continuity method” and explain how to use this method for giving answers to the questions posed in the first part.
15h30 Volker Schlue (Paris)
On the nonlinear stability of expanding black hole cosmologies
Monday December 12, 2016
room 15/25-102
14h Michał Wrochna (Grenoble)
The quantum stress-energy tensor and its intricate relationship with spacetime geometry
Abstract. It is widely believed that at low energies, quantum gravity should yield an effective theory described by Einstein equations with a stress-energy tensor made of averaged fluctuations of quantum fields. The construction of that stress-energy tensor is however very problematic and its intricate dependence on spacetime geometry results in highly non-linear equations that possess no qualitative theory to date. In this talk I will review this problem as a motivation for improving the construction of linear Klein-Gordon quantum fields, and discuss recent progress that allows for a better control of the dependence on the spacetime metric (partly based on joint work with Christian Gérard).
15h30 Guillaume Idelon-Riton (Regensburg)
Some results about the scattering theory for the massive Dirac fields in the Schwarzschild-Anti-de Sitter space-time
Abstract. I will first give a brief presentation of the Schwarzschild-Anti-de Sitter spacetime and of some of its geometrical properties that will concern us. Then I will present the massive Dirac equation in this space-time and first study the Cauchy problem which is not completely obvious since our spacetime is not globally hyperbolic. I will then give a result concerning the asymptotic completeness for these fields. By means of a Mourre estimate, it is possible to obtain that the minimal velocity for these fields is 1. I will then show that our dynamics behaves in asymptotic regions like a transport at unit speed in the direction of the black hole. In a third part, I will study the local energy decay for these fields. First, using the existence of exponentially accurate quasi-modes, I will show a logarithmic lower bound on the local energy decay which is in accordance with the results of G. Holzegel and J. Smulevici in the Kerr-Anti-de Sitter spacetime for the Klein-Gordon fields. In order to obtain an upper bound, I will prove the existence of resonances and give some tools in order to localize them.
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Workshop 2016
“Modeling and Computation of Shocks and Interfaces”
Laboratoire Jacques-Louis Lions
Université Pierre et Marie Curie, Paris
Organizers
Philippe G. LeFloch (Paris)
Charalambos Makridakis (Brighton)
Supported by the ModCompShock ITN project
and a project PICS CNRS
Dec. 6 around 1:30pm to Dec. 8 around 1pm
Main speakers
Remi Abgrall (Zurich)
Benjamin Boutin (Rennes)
Christophe Chalons (Versailles)
Sergey Gavrilyuk (Marseille)
Charalambos Makridakis (Brighton)
Pierangelo Marcati (L’Aquila)
Siddhartha Mishra (Zurich)
Carlos Pares (Malaga)
Nils Risebro (Oslo)
Giovanni Russo (Catania)
Lev Truskinovsky (Palaiseau)
Titles of the lectures
Benjamin Boutin Numerical boundary layers for linear hyperbolic IBVP and semigroup estimate
Christophe Chalons On the computation of non conservative products and cell averages in finite volume methods
Makridakis Charalambos Energy/entropy consistent computational methods
Sergey Gavrilyuk Shock-droplet interaction via a new hyperbolic phase field model
Pierangelo Marcati Splash singularities for incompressible viscoelatic fluids
Siddhartha Mishra Statistical solutions of systems of conservation laws
Carlos Pares Entropy stable schemes for degenerate convection-diffusion equations
Nils Risebro Numerical methods for scalar conservation laws with a stochastically driven flux
Giovanni Russo Shock capturing schemes for all Mach number flow in gas dynamics
Lev Truskinovsky Solitary waves in the FPU lattice: from quasi-continuum to anti-continuum limit
Schedule of the workshop
Tuesday afternoon
2pm-2:45pm: C. Makridakis
2:45-3:30pm: C. Pares
3:30pm: coffee break
4pm-4:45pm G. Russo
Wednesday morning
10am-10:45am: S. Gavrilyuk
10:45am: coffee break
11:15am: C. Chalons
Noon: lunch buffet
Wednesday afternoon
2pm-2:45pm R. Abgrall
2:45pm-3:30pm S. Mishra
3:30am coffee break
4pm L. Truskinovsky
Thursday morning
9:30am-10:15am N. Risebro
10:15am coffee break
10:45am B. Boutin
11:30am P. Marcati
12:15 lunch buffet (end of the workshop)
Participants to the workshop
- Remi Abgrall (Zurich) remi.abgrall at math.uzh.ch
- Benjamin Boutin (Rennes) chalons at math.jussieu.fr
- Christophe Chalons (Versailles) chalons at math.jussieu.fr
- Yangyang Cao (Paris) caoyangyang0721 at 163.com
- Marco De Lorenzo (Paris) marco.de-lorenzo at edf.fr
- Christian Dickopp (Aachen) dickopp at web.de
- Alain Forestier (Saclay) alain.forestier at cea.fr
- Sergey Gavrilyuk (Marseille) sergey.gavrilyuk at univ-amu.fr
- Maren Hantke (Magdeburg) maren.hantke at ovgu.de
- David Iampetro (Marseille) david.iampietro at edf.fr
- Philippe G. LeFloch (Paris) contact philippelefloch.org
- Charalambos Makridakis (Brighton) C.Makridakis at sussex.ac.uk
- Pierangelo Marcati (L’Aquila) pierangelo.marcati at gssi.infn.it
- Christoph Matern (Magdeburg) christoph.matern at ovgu.de
- Siddhartha Mishra (Zurich) siddhartha.mishra at sam.math.ethz.ch
- Roberto Molina (Paris) rmolina.sep at gmail.com
- Hieu Nguyen (Aachen) nguyen at instmath.rwth-aachen.de
- Carlos Pares (Malaga) pares at anamat.cie.uma.es
- Yohan Penel (Paris) penel at ann.jussieu.fr
- Chaoyu Quan (Paris) quanchaoyu at gmail.com
- Pierre-Arnaud Raviart (Paris) pa at raviart.com
- Nils Risebro (Oslo) nilshr at math.uio.no
- Giovanni Russo (Catania) russo at dmi.unict.it
- Lev Truskinovsky (Palaiseau) trusk at lms.polytechnique.fr
- Shugo Yasuda (Hyogo) yasuda at sim.u-hyogo.ac.jp
- Dimitrios Zacharenakis (Stuttgart) zachards at mathematik.uni-stuttgart.de
Other practical informations
The workshop will take place in the main lecture room 309 of the Laboratoire Jacques-Louis Lions, Université Pierre et Marie Curie, which is located in the building 15-16.
Address: 4 Place Jussieu, 75258 Paris. Subway station: Jussieu.
List of hotels in the vicinity of the university
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Organizers
Philippe G. LeFloch (Paris)
Jérémie Szeftel (Paris)
Ghani Zeghib (Lyon)
ANR Project
“Mathematical General Relativity. Analysis and geometry of spacetimes with low regularity”
Wednesday June 17, 2015
Laboratoire Jacques-Louis Lions, Université Pierre et Marie Curie, Paris
Lecture room 15/25-326
11h Emmanuel Hebey (Cergy-Pontoise) Systèmes de Kirchhoff critiques stationnaires sur des variétés compactes
14h Lydia Bieri (Ann Arbor) Gravitational radiation and two types of memory
Abstract. We are believed to live on the verge of detection of gravitational waves, which are predicted by General Relativity. In order to understand gravitational radiation, we have to investigate analytic and geometric properties of corresponding solutions to the Einstein equations. Gravitational waves leave a footprint in the spacetime regions they pass, changing the manifold – and therefore displacing test masses – permanently. This is known as the memory effect. It has been believed that for the Einstein equations, being nonlinear, there exists one such effect with a small `linear’ and a large `nonlinear’ part. In this talk, I present some of my joint work with D. Garfinkle showing that these are in fact two different effects.
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Organizers
Philippe G. LeFloch (Paris)
Jérémie Szeftel (Paris)
Ghani Zeghib (Lyon)
ANR Project
“Mathematical General Relativity. Analysis and geometry of spacetimes with low regularity”
Wednesday May 27, 2015
Laboratoire Jacques-Louis Lions, Université Pierre et Marie Curie, Paris
Lecture room 15-25–326
14h Thierry Barbot (Avignon) Surfaces polygonales fuchsiennes et espace de Teichmüller décoré
Abstract. Dans l’article “Fuchsian polyhedra in Lorentzian space-forms, Mathematische Annalen 350, 2, pp. 417-453, 2011″, F. Fillastre a montré que toute métrique euclidienne avec singularités coniques d’angles > 2 pi sur une surface compacte se réalise de manière unique comme une surface de Cauchy polygonale dans un espace-temps globalement hyperbolique localement plat radial (i.e. dont le groupe d’holonomie fixe un point de l’espace de Minkowski). Dans cet exposé, j’évoquerai le travail de L. Brunswic dans son travail de thèse sous ma direction, qui vise à reprouver ce résultat et à l’étendre au cas des surfaces polygonales dans un espace-temps localement plat mais admettant des particules massives. Le but est de montrer qu’il y a encore existence et unicité une fois prescrit la masse des particules massives (le cas régulier montré par Fillastre correspondant au cas où l’angle singulier des particules massives est 2pi). Je montrerai aussi que la situation étudiée par R. Penner dans l’article “The Decorated Teichmϋller Space of Punctured Surfaces, Commun. Math. Phys. 113, 299-339 (1987)” est un cas limite de la situation étudiée par Brunswic, et correspond au cas où les particules sont d’angle conique nul. Je montrerai aussi comment répondre positivement à la question dans le cas où il n’y a qu’une singularité.
15h30 Andrea Seppi (Pavia) Convex surfaces in (2+1)-dimensional Minkowski space
Abstract. It is known that the hyperbolic plane admits an isometric embedding into Minkowski space; in 1983 Hanu and Nomizu first observed the existence of non-equivalent isometric embeddings, thus showing a relevant difference with the Euclidean case. In this talk, I will introduce some natural properties of a convex surface in Minkowski space, concerning causality and asymptotic behavior. I will then explain some new results (jointly with Francesco Bonsante) on the classification of constant curvature surfaces with bounded principal curvatures and on the solvability of Minkowski problem in (2+1)-dimensional Minkowski space. If time permits, I will give the main ideas of the proof and especially the relation to some type of Monge-Ampere equations.
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Organizers
Philippe G. LeFloch (Paris)
Jérémie Szeftel (Paris)
Ghani Zeghib (Lyon)
ANR Project
“Mathematical General Relativity. Analysis and geometry of spacetimes with low regularity”
Wednesday April 15, 2015
Laboratoire Jacques-Louis Lions, Université Pierre et Marie Curie, Paris
Lecture room 15-25–326
14h Shiwu Yang (Cambridge) Decay properties of solutions of Maxwell Klein-Gordon equations
Abstract. I will present some recent progress on the asymptotic behavior of global solutions to Maxwell-Klein-Gordon equations. I will show that the integrated local energy and the energy flux through the outgoing null hypersurfaces decays polynomially in the retarded time in Minkowski space with data merely bounded in some gauge invariant weighted Sobolev space. This in particular includes the case with large charge. One novelty of this work is that these decay estimates precisely capture the asymptotic properties for the non-linear fields with arbitrarily large data. If in addition that the initial data for the scalar field is sufficiently small, then we show the pointwise decay of the solutions. This result improves the previous result of Lindblad and Sterbenz in which smallness is required for both the scalar field and the Maxwell field.
15h30 Gustav Holzegel (London) Local and global dynamics in asymptotically anti de Sitter spacetimes
Abstract. Asymptotically anti de Sitter (aAdS) spacetimes play a prominent role in theoretical physics and mathematics. Due to the presence of a timelike hypersurface at infinity these spacetimes are not globally hyperbolic, a fact that leads to intricate initial boundary value problems when studying global dynamics of hyperbolic equations on these backgrounds. In this talk, I will present several local and global results for the massive wave equation on aAdS spacetimes (including black hole spacetimes) with emphasis on how different boundary conditions (Dirichlet, Neumann or dissipative) influence the global dynamics. In particular, I will outline a recent proof (obtained in collaboration with J. Luk, J. Smulevici and C. Warnick) of linear stability and decay for gravitational perturbations on anti de Sitter space under dissipative boundary conditions. The proof unravels an interesting trapping phenomenon near the conformal boundary which necessarily leads to a degeneration in the decay estimates. Time permitting some future applications will also be discussed.