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 at LPTHE  
[ scheduler view ] 
Thursday 21 March 2019, 11:00 at LPTHE, bibliothèque du LPTHE, tour 1314, 4eme étage  SEMDARBOUX (Séminaire Darboux  physique théorique et mathématiques)  hepth 



Abstract:  We study the eigenfunctions of discrete Schrödinger operators on finite graphs of large size, and their (de)localization properties. To measure delocalization, we use a criterion of "quantum ergodicity" borrowed from the subject of quantum chaos. We can prove delocalization in this sense for some families of graphs, typically : regular graphs and their small perturbations. We show that quantum ergodicity is related to ``spectral delocalization'', namely the fact that the spectrum of the ideal infinite system is absolutely continuous. 
Friday 22 March 2019, 11:00 at LPTHE, Bibliothèque  SEMLPTHE (Séminaire du LPTHE)  condmat.statmechhepth 



Abstract:  We review the effect of introducing anisotropic couplings for lattice gauge theories and show that these can lead to new, ``layered'', phases, beyond the bulk confining and Coulomb phases, known in abelian gauge theories. The new phases can be interpreted as describing the effects of flux compactifications and generalize the KaluzaKlein paradigm of extra dimensions. Extra dimensions have been, in fact, used to describe defects in condensed matter systems and anisotropic gauge theories can be also understood as allowing the description of more elaborate defects. Coupling matter to the gauge fields leads to a consistent, nonperturbative, description of chiral fermions, provided the anomalies are properly cancelled, and can describe edge states and their currents while scalar fields lead to a quite elaborate phase diagram. The challenges of assembling these ingredients to study supersymmetric theories will be touched on, as a way of describing how such systems can be consistently closed, a la ParisiSourlas. 
Tuesday 26 March 2019, 14:00 at LPTHE, library  LPTHEPPH (Particle Physics at LPTHE)  hepphhepth 



Abstract:  Twoloop scattering amplitudes are a vital component in highprecision cross section calculations at the LHC. At higher multiplicities, the increased number of scales can make the algebra of analytic amplitude calculations intractable. In this talk, we discuss how to apply numerical techniques to sidestep this intermediate complexity and combine them with physical properties of the amplitude to efficiently determine its analytic form. In particular we focus on planar fivepoint amplitudes in QCD. 
Thursday 28 March 2019, 10:00 at IHP, 201  RENCTHEO (Rencontres Théoriciennes)  hepth 



Abstract:  I will review recent developments on soft gravitational radiation from ultrarelativistic collisions. Calculations based on recent developments in the eikonal approach and in softgraviton theorems can be successfully compared in their common region of applicability. Combining the results of both approaches leads to a knee in the spectrum at a typical "Hawking frequency” and to a bump at wavelengths comparable to the impact parameter of the collision. 
Thursday 28 March 2019, 11:40 at IHP, 201  RENCTHEO (Rencontres Théoriciennes)  hepth 


Friday 29 March 2019, 11:00 at LPTHE, Bibliothèque  SEMLPTHE (Séminaire du LPTHE)  condmat.statmechhepthmathmathphmath.AG 



Abstract:  The dimer model is a model from statistical mechanics corresponding to random perfect matchings on graphs. Circle patterns are a class of embeddings of planar graphs such that every face admits a circumcircle. In this talk I describe a correspondence between dimer models on planar bipartite graphs and circle pattern embeddings of these graphs. As special cases of this correspondence we recover the Tutte embeddings for resistor networks and the sembeddings for Ising models. This correspondence is also the key for studying Miquel dynamics, a discrete integrable system on circle patterns. 
Thursday 4 April 2019, 11:00 at LPTHE, bibliothèque du LPTHE, tour 1314, 4eme étage  SEMDARBOUX (Séminaire Darboux  physique théorique et mathématiques)  hepth 


Thursday 11 April 2019, 11:00 at IHP, 314  RENCTHEO (Rencontres Théoriciennes)  hepth 


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


Tuesday 16 April 2019, 14:00 at LPTHE, library  LPTHEPPH (Particle Physics at LPTHE)  hepph 


Tuesday 30 April 2019, 14:00 at LPTHE, library  LPTHEPPH (Particle Physics at LPTHE)  hepph 


Thursday 9 May 2019, 10:00 at IHP, 314  RENCTHEO (Rencontres Théoriciennes)  hepth 


Thursday 9 May 2019, 11:40 at IHP, 314  RENCTHEO (Rencontres Théoriciennes)  hepth 


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


Thursday 16 May 2019, 11:00 at LPTHE, bibliothèque du LPTHE, tour 1314, 4eme étage  SEMDARBOUX (Séminaire Darboux  physique théorique et mathématiques)  hepth 


Friday 17 May 2019, 14:00 at LPTHE, library  LPTHEPPH (Particle Physics at LPTHE)  hepph 


Thursday 23 May 2019, 10:00 at IHP, 314  RENCTHEO (Rencontres Théoriciennes)  hepth 


Thursday 23 May 2019, 11:40 at IHP, 314  RENCTHEO (Rencontres Théoriciennes)  hepth 


Friday 7 June 2019, 14:00 at LPTHE, library  LPTHEPPH (Particle Physics at LPTHE)  hepph 


Thursday 13 June 2019, 10:00 at IHP, 314  RENCTHEO (Rencontres Théoriciennes)  hepth 


Thursday 13 June 2019, 11:40 at IHP, 314  RENCTHEO (Rencontres Théoriciennes)  hepth 


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


Thursday 20 June 2019, 10:00 at IHP, Salle 314  RENCTHEO (Rencontres Théoriciennes)  hepth 


Thursday 20 June 2019, 11:40 at IHP, 314  RENCTHEO (Rencontres Théoriciennes)  hepth 


Thursday 27 June 2019, 11:00 at LPTHE, bibliothèque du LPTHE, tour 1314, 4eme étage  SEMDARBOUX (Séminaire Darboux  physique théorique et mathématiques)  hepth 



[ English version ] 