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 ] 
Wednesday 26 April 2017, 14:15 at IPHT, Salle Claude Itzykson, Bât. 774  IPHTMAT (Séminaire de matrices, cordes et géométries aléatoires)  hepth 



Abstract:  This talk addresses the problem of counting the microstates of supersymmetric asymptotically AdS black holes in terms of a holographically dual field theory. We focus on a particular BPS class of AdS$_2 x S^2$ nearhorizon geometry in N=2 gauged supergravity relevant both for AdS$_4$ and AdS$_5$ black holes. We consider in the large N limit the topologically twisted index of the ABJM theory and the partition function of N=4 SYM and show that they correctly reproduce the BekensteinHawking entropy of the AdS$_4$ and AdS$_5$ black holes, respectively. An extremization of the partition functions with respect to a set of chemical potentials is required. We interpret it as the selection of the exact Rsymmetry of the superconformal quantum mechanics describing the horizon of the black holes. 
Thursday 27 April 2017, 11:00 at LPTENS, LPTENS library  STRINT (Strings, integrability and beyond)  hepth 



Abstract:  Extremal black hole backgrounds provide an interesting generalization of holography beyond the AdS/CFT correspondence and closer to the real world. I will review the universal properties that the holographic duals to extremal black holes, which I will refer to as "dipole" CFT_2s, are expected to have, and show these properties are shared by the duals of certain integrable string theory backgrounds. I will then discuss higherdimensional generalizations of dipole CFTs and their relation to nonrelativistic CFTs in one dimension less. Finally, I will present a concrete fourdimensional example of a dipole CFT, which is the null dipole deformation of N=4 SYM introduced by Ganor et al. 
Thursday 27 April 2017, 14:00 at LPTM, 4.13 St Martin II  SEMLPTMUCP (Seminaires du LPTM , Universite de Cergy Pontoise)  quantph 



Abstract:  In the first part of the talk, I consider the nonequilibrium time evolution of piecewise homogeneous states in the XXZ spin1/2 chain. I overview the solution to the dynamics in the limit of large time and discuss some remarkable properties of the profiles of charges and currents. In the second part of the talk, I describe an unusual mechanism of prethermalization, based on the presence of a symmetry of the prequench Hamiltonian which is spontaneously broken at zero temperature and is explicitly broken by the postquench Hamiltonian. 
Thursday 27 April 2017, 14:30 at LPTENS, LPTENS Library  STRINT (Strings, integrability and beyond)  hepth 



Abstract:  TBA 
Friday 28 April 2017, 10:00 at
IPHT,
Salle Claude Itzykson, Bât. 774 ( https://courses.ipht.cnrs.fr/?q=fr/node/167 )  COURS (Cours)  hepph 



Abstract:  The methods and ideas of Effective Field Theory (EFT) are among the most powerful and deep organising principles in physics, and particularly so in Quantum Field Theory and its ramifications and applications into particle physics, condensed matter physics, and statistical mechanics. \par The basic idea is to approximate a physical system by integrating out the degrees of freedom that are not relevant in a given experimental setting. These are traded for a set of effective interactions between the remaining degrees of freedom. \par In these lectures we will review the concept, techniques, and applications of the EFT framework. \\  Overview of the EFT landscape : Prominent examples including Fermi theory, the HeisenbergEuler Lagrangian, and chiral perturbation theory. \\  Integrating out heavy particles : Quantitative discussion of the procedure in a quantum field theory. Explicit example of the tree and oneloop level matching between an EFT and its UV completion. \\  Beyond the Standard Model : Introduction of the Standard Model EFT by extending the Standard Model Lagrangian with nonrenormalizable interactions representing the effects of new heavy particles. \\  Functional integration methods and EFTs for classical systems.  
Attachments: 
Friday 28 April 2017, 10:30 at
IHES,
Amphithéâtre Léon Motchane ( Cours des professeurs permanents de l'IHES )  MATHIHES (TBA)  hepth 


Friday 28 April 2017, 11:00 at CPHT, Salle de conférences, bât. 6  IPNX (Séminaire commun de physique théorique des particules IPNCPHTX)  hepph 



Abstract:  We investigate the effects of (axial)vector mesons on the chiral phase transition of the model containing 2+1 constituent quarks and Polyakovloop degrees of freedom. A chi^2 minimization procedure is used to parameterize the model based on treelevel decay widths and vacuum scalar and pseudoscalar curvature masses which includes the vacuum and thermal contribution of the constituent quarks. The pressure and the derived thermodynamical observables determined from it at finite temperature T and chemical potential µ using a simple approximation for the grand potential are compared to lattice results. The best parametrization of the model allows for the existence of the critical end point (CEP) of the µ–T phase diagram. 
Friday 28 April 2017, 11:30 at SAMM, C20.13, Centre Pierre MendèsFrance, Univ. Paris1, 90 rue de Tolbiac, Paris  SAMM (Statistics, Analysis, Multidisciplinary Modeling)  math.ST 


Friday 28 April 2017, 14:00 at IPHT, Salle Claude Itzykson, Bât. 774  IPHTHEP (Séminaire de physique des particules et de cosmologie)  hepph 



Abstract:  Binding of particles in atoms changes their properties such as the magnetic moment. In case of unstable particles like the muon, the decay spectrum is modified. In light atoms these changes should be calculable within quantum electrodynamics with high precision. Such theoretical predictions are needed for the determination of the electron mass and of the fine structure constant, and for searches of leptonflavor violation. I will review the recent progress and remaining challenges. I will point out some qualitative changes caused even by very weak binding, showing that the binding is a singular perturbation. 
Tuesday 2 May 2017, 10:30 at
IHES,
Centre de conférences Marilyn et James Simons ( Cours des professeurs permanents de l'IHES )  MATHIHES (TBA)  hepth 


Tuesday 2 May 2017, 14:00 at APC, 483 A  Malevitch  APCTH (Seminar of the theory group of APC)  hepth 


Wednesday 3 May 2017, 10:30 at
IHES,
Centre de conférences Marilyn et James Simons ( Séminaire Mathématique ParisTunis )  MATHIHES (TBA)  hepth 



Abstract:  Les problématiques de formation de singularité en équations aux dérivées partielles nonlinéaires sont au coeur d'une dynamique de recherche intense ces vingt dernières années. Je présenterai quelques résultats récents concernant la construction de solutions explosives dans le cadre dit énergie sur critique. Dans le cas parabolique, je présenterai notamment la construction de toutes nouvelles bulles a géométrie fortement anisotrope. 
Wednesday 3 May 2017, 11:45 at
IHES,
Centre de conférences Marilyn et James Simons ( Séminaire Mathématique ParisTunis )  MATHIHES (TBA)  hepth 



Abstract:  Le but de l'exposé est de présenter un résultat d'existence et d'unicité globales pour le système magnétohydrodynamique incompressible en 3D pour des données initiales assez proches de l'état d'équilibre e_3=(0,0,1). 
Wednesday 3 May 2017, 15:00 at LPTM, 4.13 St Martin II  SOUTENTH (Soutenance de thèse)  condmat 


Thursday 4 May 2017, 10:00 at IHP, 314  RENCTHEO (Rencontres Théoriciennes)  hepth 



Abstract:  tba 
Thursday 4 May 2017, 11:00 at LPTHE, Bibliothèque  SEMINFOR (Séminaire informel)  condmatcondmat.statmechmathph 



Abstract:  I will show how the thermodynamic limit of integrable models can be used to isolate their relevant excitations, responsible for the local physics. In particular I will show how the “dressed” nature of such excitations, which is due to the presence of nontrivial interparticle interactions, manifests in matrix elements of local observables, nonequilibrium steady states like Generalized Gibbs Ensembles and Hydrodynamics. 
Thursday 4 May 2017, 11:45 at IHP, 314  RENCTHEO (Rencontres Théoriciennes)  hepth 



Abstract:  tba 
Thursday 4 May 2017, 13:30 at DPTPHYSENS, room Conf. IV, 24 Rue Lhomond, ENS Paris  SEMPHYSENS (Colloquium du Département de Physique de l'ENS)  condmat.statmech 


Friday 5 May 2017, 10:00 at
IPHT,
Salle Claude Itzykson, Bât. 774 ( https://courses.ipht.cnrs.fr/?q=fr/node/167 )  COURS (Cours)  hepph 



Abstract:  The methods and ideas of Effective Field Theory (EFT) are among the most powerful and deep organising principles in physics, and particularly so in Quantum Field Theory and its ramifications and applications into particle physics, condensed matter physics, and statistical mechanics. \par The basic idea is to approximate a physical system by integrating out the degrees of freedom that are not relevant in a given experimental setting. These are traded for a set of effective interactions between the remaining degrees of freedom. \par In these lectures we will review the concept, techniques, and applications of the EFT framework. \\  Overview of the EFT landscape : Prominent examples including Fermi theory, the HeisenbergEuler Lagrangian, and chiral perturbation theory. \\  Integrating out heavy particles : Quantitative discussion of the procedure in a quantum field theory. Explicit example of the tree and oneloop level matching between an EFT and its UV completion. \\  Beyond the Standard Model : Introduction of the Standard Model EFT by extending the Standard Model Lagrangian with nonrenormalizable interactions representing the effects of new heavy particles. \\  Functional integration methods and EFTs for classical systems.  
Attachments: 
Friday 5 May 2017, 10:30 at
IHES,
Centre de conférences Marilyn et James Simons ( Cours des professeurs permanents de l'IHES )  MATHIHES (TBA)  hepth 


Tuesday 9 May 2017, 10:30 at
IHES,
Amphithéâtre Léon Motchane ( Cours des professeurs permanents de l'IHES )  MATHIHES (TBA)  hepth 


Tuesday 9 May 2017, 14:00 at
IPHT,
Amphi Bloch. Bât 774 ( http://phbrax.wixsite.com/gravite )  WORKCONF (Workshop or Conference)  physics 



Abstract:  La relativité générale vient tout juste de fêter son centenaire. Les ondes gravitationnelles, une des grandes conséquences de la théorie d'Einstein, viennent d'être détectées par l'expérience LIGO. Cette observation a confirmé la dynamique des trous noirs, eux aussi conséquence de la relativité générale. Il nous semble ainsi d'extrême importance et de grande actualité de faire le point sur la nature de la gravité : à la fois du point de vue des grandes avancées récentes et des questions fondamentales qui restent en suspens. \par Dans ce but nous proposons d'organiser une conférence sur 2 jours à l'Orme des Merisiers qui portera sur ``Qu'estce que la gravité'' les 9 et 10 mai 2017. Cette rencontre réunira des orateurs de divers horizons venant à la fois de la physique, théorique ou expérimentale, et des sciences humaines. Elle couvrira des aspects historiques, physiques et épistémologiques. La relativité générale est une théorie qui a ses limites, quantiques ou cosmologiques, et ses possibles extensions seront aussi discutées. \\ \\ http://phbrax.wixsite.com/gravite \\ \\ Organisateurs : Philippe Brax, Etienne Klein and Pierre Vanhove.  
Attachments: 
Wednesday 10 May 2017, 11:00 at LPTHE, Bibliothèque  SEMINFOR (Séminaire informel)  hepthmathmathphmath.AGmath.COmath.KTmath.MPmath.QA 



Abstract:  Schubert calculus is a branch of enumerative geometry, which deals with configurations of linear subspaces of a vector space. Translated into the modern language, it amounts to certain calculations in the cohomology ring of Grassmannians and flag varieties. A practical problem is to give a combinatorial rule for the structure constants of that ring. A few years ago, I observed that there was a hidden quantum integrability in the case of Grassmannians (for which the combinatorial rule is the socalled LittlewoodRichardson rule). In a somewhat unrelated development, there has been a growing body of work (including my own) showing the deep connection between cohomology theories (ordinary cohomology, Ktheory, elliptic cohomology) and quantum integrable systems. In particular Maulik and Okounkov introduced a nice framework for this connection. It is natural to try to reinterpret my observation above in this language. After introducing these various concepts, I shall present recent work with A. Knutson in this direction. In particular, this provides completely new rules for the calculation of structure constants of the equivariant cohomology or Ktheory of dstep flag varieties for d smaller or equal to 4, thus moving several "steps" closer to the completion of the program of Schubert calculus. 
Wednesday 10 May 2017, 14:15 at IPHT, Salle Claude Itzykson, Bât. 774  IPHTMAT (Séminaire de matrices, cordes et géométries aléatoires)  hepth 


Wednesday 10 May 2017, 16:00 at IPHT, Salle Claude Itzykson, Bât. 774  IPHTSEM (Séminaire du IPHT)  physics 



Abstract:  Significant experimental and theoretical activity at the LHC is dedicated to the study of an elusive state of matter, the quarkgluon plasma, created in headon heavyion collisions. Measurements of fully reconstructed jets in these collisions allow to study new aspects of this exotic state via its coupling to perturbative degrees of freedom. We discuss how energetic colour charges propagate in a quarkgluon plasma and extend the previously known formalism to compute energyloss of independent partons to treat neighbouring partons within the same jet. This extension accounts for the coherent structure of jet fragmentation and implies subtle modifications of the substructure. As a concrete application, we discuss the expected mediummodification of the jet splitting probability that is measured using jet grooming procedures and discuss generic strategies to enhance the sensitivity to medium effects. \\ \\ (IPhT organizer: Edmond Iancu) 
Thursday 11 May 2017, 13:30 at DPTPHYSENS, room Conf. IV, 24 Rue Lhomond, ENS Paris  SEMPHYSENS (Colloquium du Département de Physique de l'ENS)  physics.geoph 


Thursday 11 May 2017, 15:00 at LPTENS, LPTENS Library  COURS (Cours)  hepth 



Abstract:  I will review some recent developments of type II and heterotic superstring field theory. The approach I will follow is due to Ashoke Sen and based on the construction of the openclosed bosonic string field theory by Zwiebach. Particular attention will be devoted to the three main challenges faced by superstring field theory: inclusion of the Ramond sector, removal of spurious singularities due to the superconformal ghosts and definition of a prescription for the offshell amplitudes. The plan is the following: 1) motivations, divergences in (super)string theory and offshell amplitudes; 2) superstring field theory: gauge fixed and quantum action, construction of the Ramond sector 3) momentum representation of amplitudes, applications: unitarity, soft theorems 
Friday 12 May 2017, 10:00 at
IPHT,
Salle Claude Itzykson, Bât. 774 ( https://courses.ipht.cnrs.fr/?q=fr/node/167 )  COURS (Cours)  hepph 



Abstract:  The methods and ideas of Effective Field Theory (EFT) are among the most powerful and deep organising principles in physics, and particularly so in Quantum Field Theory and its ramifications and applications into particle physics, condensed matter physics, and statistical mechanics. \par The basic idea is to approximate a physical system by integrating out the degrees of freedom that are not relevant in a given experimental setting. These are traded for a set of effective interactions between the remaining degrees of freedom. \par In these lectures we will review the concept, techniques, and applications of the EFT framework. \\  Overview of the EFT landscape : Prominent examples including Fermi theory, the HeisenbergEuler Lagrangian, and chiral perturbation theory. \\  Integrating out heavy particles : Quantitative discussion of the procedure in a quantum field theory. Explicit example of the tree and oneloop level matching between an EFT and its UV completion. \\  Beyond the Standard Model : Introduction of the Standard Model EFT by extending the Standard Model Lagrangian with nonrenormalizable interactions representing the effects of new heavy particles. \\  Functional integration methods and EFTs for classical systems.  
Attachments: 
Friday 12 May 2017, 10:30 at
IHES,
Amphithéâtre Léon Motchane ( Cours des professeurs permanents de l'IHES )  MATHIHES (TBA)  hepth 


Monday 15 May 2017, 11:00 at IPHT, Salle Claude Itzykson, Bât. 774  IPHTPHM (Séminaire de physique mathématique)  mathph 



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