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Monday 2 December 2019, 14:00 at LPTM, 4.13 St Martin II  SEMLPTMUCP (Seminaires du LPTM , Universite de Cergy Pontoise)  mathph 



Abstract:  Growing uncertainty from renewable energy integration and distributed energy resources motivate the need for advanced tools to quantify the effect of uncertainty and assess the risks it poses to secure system operation. In general, Uncertainty Quantification (UQ) methods are used in complex systems research to give probabilistic guarantees. I will introduce the context of this work, as well as the Polynomial chaos expansion (PCE) method that has been recently proposed as a tool for UQ in Power Systems. The method produces results that are highly accurate, but are computationally challenging to scale to large systems. We propose a modified algorithm based on PCE and using the system sparsity with significantly improved computational efficiency while retaining the desired high level of accuracy. In an example, we show how to solve the so called chance constrained power flow problem, e.g. we need a solution such that the power transmitted trough the lines should be lower than some safe value 99 percent of the time. 
Tuesday 3 December 2019, 10:00 at
IPHT,
Salle Claude Itzykson, Bât. 774 ( https://courses.ipht.cnrs.fr/?q=fr/node/245 )  COURS (Cours)  condmat 



Abstract:  In this series of lectures we will give a broad view of topological systems, including topological insulators, quantum Hall effect, and topological superconductors. We will discuss the properties of Majorana states and other topological edge states in both onedimensional and twodimensional systems, as well as the techniques to study the formation of these states and their properties. \par Integer and fractional quantum Hall effects will be discussed notably using the composite fermion contruction of wavefunctions. We will describe fractional charge and statistics of the quantum Hall states and their effective field theoretic description. The pfaffian state proposed to describe the elusive $\nu =5/2$ state will be also decribed.\\ The program of the lectures will include: \\ 1 Topology in solid state systems; Examples of topological materials and topological edge states (e.g. Majorana) \\ 2 Analytical and numerical techniques to derive the formation of edge states \\ 3 2D electronic systems, Landau levels, integer and fractional quantum Hall effect \\ 4 The Laughlin wavefunction, more fractions composite fermions \\ 5 Multicomponent systems: spins and interlayer phase coherence, quantum Hall ferromagnetism \\ 6 The pfaffian state and its excitations.  
Attachments: 
Tuesday 3 December 2019, 11:00 at CPHT, Salle Louis Michel  SEMCPHT (Séminaire du CPHT)  hepth 



Abstract:  The linchpin of nAdS2/nCFT1 is the nonlinear realization of symmetries, where the conformal symmetry of AdS2 is spontaneously broken and also broken by an anomaly. In this talk I'll discuss the corner of this correspondence that is relevant for the holographic description of the nearextremal Kerr black hole. 
Tuesday 3 December 2019, 11:30 at LPTENS, LPT Library  COURS (Cours)  hepth 



Abstract:  In this talk I will study the scaling dimension of the lightest operator of charge $n$ in the $U(1)$ model at the WilsonFisher fixed point in $4\varepsilon$ dimensions. Even for a perturbatively small fixed point coupling $\lambda$, standard perturbation theory breaks down for sufficiently large $\lambda n$. Treating $\lambda n$ as fixed for small $\lambda $, I will show that the scaling dimension can be successfully computed through a semiclassical expansion around a nontrivial trajectory, resulting in a series in the coupling whose coefficients are fixed functions of $\lambda n$. I will discuss explicitly the computation of the first two orders in the expansion. The result, when expanded at small $\lambda n$, perfectly agrees with all available diagrammatic computations. The asymptotic at large $\lambda n$ reproduces the systematic large charge expansion, recently derived in CFT. Similar results can be derived in the $U(1)$ model in $3\varepsilon$ dimensions. I will briefly comment on the application of similar ideas in the calculation of other observables, such as threepoint functions of charged operators. 
Tuesday 3 December 2019, 14:00 at CPHT, Salle Louis Michel, CPHT, Ecole Polytechnique  SEMCPHT (Séminaire du CPHT)  hepth 


Wednesday 4 December 2019, 11:00 at LPTHE, bibliothèque du LPTHE, tour 1314, 4eme étage  SEMEXCEP (Séminaire exceptionel)  hepth 



Abstract:  Ftheory GUTs have attracted considerable interest over the recent years. In the first part of this talk, the basic ingredients for Ftheory model building will be reviewed and some viable FGUTs will be presented. In the second part, possible solutions regarding the moduli stabilisation problem, the existence of de Sitter vacua and inflation will be discussed. 
Wednesday 4 December 2019, 11:00 at LPTMC, Jussieu tower 1312, 5th floor, room 523  SEMLPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée)  condmat.meshall 


Wednesday 4 December 2019, 14:15 at
IPHT,
Salle Claude Itzykson, Bât. 774 ( https://www.ipht.fr/Phocea/Vie_des_labos/Seminaires/index.php?id=993953 )  IPHTMAT (Séminaire de matrices, cordes et géométries aléatoires)  hepth 


Thursday 5 December 2019, 10:00 at IHP, 314  RENCTHEO (Rencontres Théoriciennes)  hepth 


Thursday 5 December 2019, 11:40 at IHP, 314  RENCTHEO (Rencontres Théoriciennes)  hepth 


Friday 6 December 2019, 14:00 at LPTHE, library  LPTHEPPH (Particle Physics at LPTHE)  hepph 


Monday 9 December 2019, 10:45 at LPTMC, Jussieu, tower 1312, room 523  SEMLPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée)  condmat.meshall 


Monday 9 December 2019, 13:30 at LPENS, Conf IV  LPA (Séminaire du laboratoire Pierre Aigrain)  condmat 


Monday 9 December 2019, 14:30 at
IHES,
Amphithéâtre Léon Motchane ( Séminaire Géométrie et groupes discrets )  MATHIHES (TBA)  hepth 



Abstract:  Let W be a Coxeter group. We provide a precise description of the conjugacy classes in W, yielding an analogue of Matsumoto's theorem for the conjugacy problem in arbitrary Coxeter groups. This extends to all Coxeter groups an important result on finite Coxeter groups by M. Geck and G. Pfeiffer from 1993. In particular, we describe the cyclically reduced elements of W, thereby proving a conjecture of A. Cohen from 1994. 
Monday 9 December 2019, 16:30 at
IHES,
Amphithéâtre Léon Motchane ( Séminaire Géométrie et groupes discrets )  MATHIHES (TBA)  hepth 



Abstract:  To sum up: We will define complementary series for hyperbolic groups and prove their irreducibility. More precisely: The complementary series representations are a family of unitary representations that can be realized on the Gromov boundary of the hyperbolic group. They can be viewed as a oneparameter deformation of the quasiregular representation arising on the boundary, "sometimes" approaching the trivial representation, in a certain sense. The starting point of this work is to find a suitable scalar product in order to unitarize the complementary series. Then, a spectral estimates combined with counting estimates enable us to prove an ergodic theorem à la BaderMuchnik to achieve the irreducibility. Joint work with Kevin Boucher and JeanClaude Picaud. 
Tuesday 10 December 2019, 11:00 at CPHT, Salle Louis Michel, CPHT, Ecole Polytechnique  SEMCPHT (Séminaire du CPHT)  hepth 


Wednesday 11 December 2019, 12:00 at LPENS, Conf. IV  FORUMENS (Forum de Physique Statistique @ ENS)  condmat.statmech 


Wednesday 11 December 2019, 14:00 at LPTMC, Jussieu tower 1312 5th floor room 523  SEMLPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée)  condmat.meshall 


Thursday 12 December 2019, 11:00 at LPTHE, bibliothèque du LPTHE, tour 1314, 4eme étage  SEMDARBOUX (Séminaire Darboux  physique théorique et mathématiques)  math.AG 


Friday 13 December 2019, 10:00 at
IPHT,
Salle Claude Itzykson, Bât. 774 ( https://courses.ipht.cnrs.fr/?q=fr/node/245 https://www.ipht.fr/Phocea/Vie_des_labos/Seminaires/index.php?id=993962 )  COURS (Cours)  condmat 



Abstract:  In this series of lectures we will give a broad view of topological systems, including topological insulators, quantum Hall effect, and topological superconductors. We will discuss the properties of Majorana states and other topological edge states in both onedimensional and twodimensional systems, as well as the techniques to study the formation of these states and their properties. \par Integer and fractional quantum Hall effects will be discussed notably using the composite fermion contruction of wavefunctions. We will describe fractional charge and statistics of the quantum Hall states and their effective field theoretic description. The pfaffian state proposed to describe the elusive $\nu =5/2$ state will be also decribed.\\ The program of the lectures will include: \\ 1 Topology in solid state systems; Examples of topological materials and topological edge states (e.g. Majorana) \\ 2 Analytical and numerical techniques to derive the formation of edge states \\ 3 2D electronic systems, Landau levels, integer and fractional quantum Hall effect \\ 4 The Laughlin wavefunction, more fractions composite fermions \\ 5 Multicomponent systems: spins and interlayer phase coherence, quantum Hall ferromagnetism \\ 6 The pfaffian state and its excitations.  
Attachments: 
Monday 16 December 2019, 10:45 at LPTMC, Jussieu campus, tower 1312, 5th floor, room 523  SEMLPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée)  condmat.meshall 


Monday 16 December 2019, 13:30 at LPENS, Conf IV  LPA (Séminaire du laboratoire Pierre Aigrain)  condmat 


Tuesday 17 December 2019, 14:00 at LPTHE, library  LPTHEPPH (Particle Physics at LPTHE)  hepph 



Abstract:  The observed dark matter (DM) abundance in the Universe can be fully accounted for by a minimally coupled spectator scalar field that was light during cosmic inflation. In this scenario, dark matter was produced during inflation by amplification of quantum fluctuations of the spectator field. I will discuss the DM isocurvature perturbations that are unavoidably generated in such scenarios and the circumstances under which they are not problematic for the viability of nonthermal DM models. I will also discuss implications of DM isocurvature for structure formation, showing that the model has interesting consequences which allow one to test the scenario. 
Wednesday 18 December 2019, 10:00 at IHES, Centre de conférences Marilyn et James Simons  MATHIHES (TBA)  hepth 



Abstract:  I would like to explain a classification result for pdivisible groups, which unifies many of the existing results in the literature. The main tool is the theory of prisms and prismatic cohomology recently developed by Bhatt and Scholze. This is joint work with Johannes Anschütz. 
Wednesday 18 December 2019, 12:00 at LPENS, Conf. IV  FORUMENS (Forum de Physique Statistique @ ENS)  condmat.statmech 


Wednesday 18 December 2019, 14:15 at
IPHT,
Salle Claude Itzykson, Bât. 774 ( https://www.ipht.fr/Phocea/Vie_des_labos/Seminaires/index.php?id=993956 )  IPHTMAT (Séminaire de matrices, cordes et géométries aléatoires)  hepth 


Thursday 19 December 2019, 10:00 at IHP, Salle 314  RENCTHEO (Rencontres Théoriciennes)  hepth 


Thursday 19 December 2019, 15:00 at LPTMC, Jussieu tower 1312 5th floor room 523  SEMLPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée)  condmat.meshall 


Friday 20 December 2019, 14:15 at
IPHT,
Pièce 50, Bât. 774 ( https://www.ipht.fr/Phocea/Vie_des_labos/Seminaires/index.php?id=993933 )  IPHTMAT (Séminaire de matrices, cordes et géométries aléatoires)  hepth 


Friday 20 December 2019, 15:00 at
IPHT,
Salle Claude Itzykson, Bât. 774 ( https://www.ipht.fr/Phocea/Vie_des_labos/Seminaires/index.php?id=993976 )  SOUTENHDR (Soutenance d'Habilitation à Diriger des Recherches)  physics 



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