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  
[ scheduler view ] 
Thursday 29 October 2020, 16:00 at IHP, https://ecolepolytechnique.zoom.us/j/87443683007  RENCTHEO (Rencontres Théoriciennes)  hepth 



Abstract:  Hydrodynamics is a wellestablished field with a venerable history. In this talk, I will focus on foundational aspect of hydrodynamics which came to light in recent years. Do the equations of hydrodynamics even make sense? To what degree can the crudeness of hydrodynamics be improved? What about the phenomena that hydrodynamics should describe but fails to? And how universal is it really? 
Thursday 29 October 2020, 17:00 at IHP, Amphi Darboux  IHPNONEQ (IHP Nonequilibrium 2020)  condmat 


Monday 2 November 2020, 10:45 at
LPTMC,
Online zoom seminar ( Online https://zoom.us/j/93941768511?pwd=MDhHUE1zTGRWNUJLUUQvRWU0MllGZz09 ID de réunion : 939 4176 8511 Code secret : 718320 )  SEMLPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée)  condmat.meshall 



Abstract:  Topological superconductors can support quasiparticle excitations which present unusual exchange statistics, called nonAbelian anyons. They correspond to midgap states localized in the core of a vortex or bound to the end of a nanowire. However, their unusual statistics cannot be easily demonstrated as they are immobile, and one should rely on indirect methods. Here, we propose a real space alternative which relies on the chiral motion along the edges of a topological superconductor. We present an approach which allows to inject on demand socalled edge vortices, which are piphase domain walls which propagate along the chiral edge channels, and possess nonAbelian statistics. We show that the signatures of this unusual exchange statistics can be detected in an electrical measurement. Ref:  Electrical detection of the Majorana fusion rule for chiral edge vortices in a topological superconductor, C.W.J Beenakker, A. Grabsch, Y. Herasymenko SciPost Phys. 6, 022 (2019)  Timeresolved electrical detection of chiral edge vortex braiding, I. Adagideli, F. Hassler, A. Grabsch, M. Pacholski, C.W.J. Beenakker, SciPost Phys. 8, 013 (2020)  Halfinteger charge injection by a Josephson junction without excess noise, F. Hassler, A. Grabsch, M. J. Pacholski, D. O. Oriekhov, O. Ovdat, I. Adagideli, and C. W. J. Beenakker, Phys. Rev. B 102, 045431 (2020) 
Monday 2 November 2020, 11:00 at IAP, zoom details: contact pitrou@iap.fr  SEMGRECO (Séminaire du GReCO : groupe de GRavitation et COsmologie à l'IAP)  grqc 



Abstract:  Starting from a recently constructed stealth Kerr solution of higher order scalar tensor theory involving scalar hair, we analytically construct disformal versions of the Kerr spacetime with a constant degree of disformality and a regular scalar field. While the disformed metric has only a ring singularity and asymptotically is quite similar to Kerr, it is found to be neither Ricci flat nor circular. Noncircularity has far reaching consequences on the structure of the solution. As we approach the rotating compact object from asymptotic infinity we find a static limit ergosurface similar to the Kerr spacetime with an enclosed ergoregion. However, the stationary limit of infalling observers is found to be a timelike hypersurface. A candidate event horizon is found in the interior of this stationary limit surface. It is a null hypersurface generated by a null congruence of light rays which are no longer Killing vectors. Under a mild regularity assumption, we find that the candidate surface is indeed an event horizon and the disformed Kerr metric is therefore a black hole quite distinct from the Kerr solution. 
Monday 2 November 2020, 14:00 at
LPNHE,
Amphi Charpak + Online ( Please comment the seminar organizers for obtaining Zoom connection details: seminaires@lpnhe.in2p3.fr )  LPNHE (Séminaires du LPNHE)  astroph 



Abstract:  Neutrinos have played a key role in astrophysics, from the characterization of nuclear fusion processes in the Sun to the observation of supernova SN1987A and multiple extragalactic events. The SuperKamiokande experiment has played a major part in past in these astrophysical studies by investigating low energy O(10)~MeV neutrinos, and currently exhibits the best sensitivity to the diffuse neutrino background from distant supernovae. Discovering and characterizing this elusive signal would represent a major breakthrough in astrophysics but also requires stateoftheart background removal techniques targeting cosmic muon spallation and atmospheric neutrinos. Even in case of an observation, extracting meaningful information about the mechanism of corecollapse supernovae and the history of star formation from a single neutrino spectrum will be a significant challenge. Here, I present an overview of the search for the diffuse supernova neutrino background in SuperKamiokande and discuss how this signal can be characterized in future experiments, notably in the SuperKGd upgrade. 
Tuesday 3 November 2020, 14:00 at APC, virtual  APCTH (Seminar of the theory group of APC)  grqc 



Abstract:  I will start with the overview of principles used in detecting gravitational waves with millisecond pulsars, then describe the main challenges. Finally, I will review the current status of the search focusing on the latest results by NanoGrav and EPTA collaborations. 
Thursday 5 November 2020, 11:00 at IHP, Zoom: https://zoom.us/j/91529131783 (pwd=1234)  RENCTHEO (Rencontres Théoriciennes)  hepth 



Abstract:  New instances of dualities between string compactifications can often be understood as a fibrewise application of known dualities. After a review of classic results, I will give an overview of new instances of such dualities in the context of manifolds of exceptional holonomy  G2 and Spin(7)  as well as an introduction to the physics related to such geometries. 
Thursday 5 November 2020, 17:00 at IHP, Amphi Darboux  IHPNONEQ (IHP Nonequilibrium 2020)  condmat 


Monday 9 November 2020, 10:45 at
LPTMC,
Online zoom seminar ( Online https://zoom.us/j/93249052930?pwd=RmFqMnNnVXdFZTdLWkFWY2twTVcvQT09 ID de réunion : 932 4905 2930 Code secret : 641327 )  SEMLPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée)  condmat.meshall 



Abstract:  Our modern understanding of universality, namely the independence of the critical properties of a system from its microscopic details, is based on the ideas put forward by K. Wilson and formalised within the framework of the renormalization group (RG). Despite the centrality of the subject in modern days theoretical Physics and the many decades passed since Wilson's original works, the classification of universality classes is to date largely unsolved. In recent years, however, the functional reformulation of the perturbative RG provided a simple tool to approach such a classification, extending significantly our knowledge of universality classes entailed by discrete symmetry groups in scalar field theories. In this talk, I will first introduce the technique, elucidate its keypoint features and explain why it is so effective in charting the theory space. In passing, I briefly review the theory of invariant polynomials paying particular attention to the socalled Hilbert (or Molien) series. I will then focus on three particular cases: the scalar field theories endowed with the symmetry group of regular polytopes, the randomly diluted Ising models and the more general hypercubic scalar field theories. For each of these three cases, I review the main results and suggest possible lines of future investigations. References: https://arxiv.org/abs/1902.05328 https://arxiv.org/abs/2006.12808 
Monday 9 November 2020, 11:00 at IAP, zoom details contact fumagall@iap.fr  SEMGRECO (Séminaire du GReCO : groupe de GRavitation et COsmologie à l'IAP)  astroph 



Abstract:  Gravitational wave astronomy allows us for unprecedented tests of the nature of dark compact objects to search for new exotic species of compact objects. I will give an overview, focusing on some recent results, including ringdown tests, gravitationalwave echoes, inspiral tests of the multipolar structure of supermassive objects, tests of the Kerr bound on the spin with extrememass ratio inspirals, and tidal effects. 
Tuesday 10 November 2020, 18:00 at IHP, Seminar via zoom https://ijclab.zoom.us/j/94900481972  P^3 (Particle Physics in Paris)  astrophhepphhepth 



Abstract:  The remarkable detection of gravitational waves by the LIGO/Virgo collaboration has opened a new window into the cosmos. In this colloquium we explain how particle theorists can help out with stateoftheart calculations directly relevant for gravitationalwave emission from compact astrophysical objects. The past decade has seen enormous advances in our ability to compute quantum scattering amplitudes making seemingly impossible calculations tractable. These advances include ideas such as the duality between color and kinematics, double copy relations and generalized unitarity. After introducing these concepts we explain how these ideas can be transferred to the binary black hole inspiral problem. 
Thursday 12 November 2020, 11:00 at LPTHE, bibliothèque du LPTHE, tour 1314, 4eme étage  SEMDARBOUX (Séminaire Darboux  physique théorique et mathématiques)  hepthmath.RT 


Thursday 12 November 2020, 17:00 at IHP, Amphi Darboux  IHPNONEQ (IHP Nonequilibrium 2020)  condmat 


Monday 16 November 2020, 10:45 at
LPTMC,
Online zoom seminar ( Online https://zoom.us/j/93520463813?pwd=YmYrRThkNE1pS0J0bGlHdG11SklTZz09 ID de réunion : 935 2046 3813 Code secret : 096019 )  SEMLPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée)  condmat.meshall 


Monday 23 November 2020, 10:45 at
LPTMC,
Online zoom seminar ( Online https://zoom.us/j/94339577111?pwd=OGRNQnVkdXRjR0JtWVVhRlhuSXBPUT09 ID de réunion : 943 3957 7111 Code secret : 117717 )  SEMLPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée)  condmat.meshall 


Tuesday 24 November 2020, 16:00 at IHP, Seminar via zoom https://ijclab.zoom.us/j/94900481972  P^3 (Particle Physics in Paris)  astrophhepphhepth 


Thursday 26 November 2020, 11:00 at IHP, Zoom: https://zoom.us/j/94637137722 (pwd=1234)  RENCTHEO (Rencontres Théoriciennes)  hepth 


Monday 30 November 2020, 10:45 at
LPTMC,
Online zoom seminar ( Online https://zoom.us/j/94742254686?pwd=YktiUHZTcHIySnBLZlgyblZMQ0VtUT09 ID de réunion : 947 4225 4686 Code secret : 769824 )  SEMLPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée)  condmat.meshall 


Monday 14 December 2020, 16:00 at
LPTMC,
Online zoom seminar ( Online https://zoom.us/j/96903025813?pwd=SjNLV2FERjJFcjlRY1crY0FFL0Q0dz09 ID de réunion : 969 0302 5813 Code secret : 007425 )  SEMLPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée)  condmat.meshall 


Tuesday 12 January 2021, 17:00 at IHP, Seminar via zoom https://ijclab.zoom.us/j/94900481972  P^3 (Particle Physics in Paris)  hepth 


Tuesday 26 January 2021, 16:00 at IHP, Seminar via zoom https://ijclab.zoom.us/j/94900481972  P^3 (Particle Physics in Paris)  astrophhepph 



Abstract:  In this talk I will highlight some special experimental capabilities of future liquid argon time projection chamber (LArTPCs) neutrino experiments like the Fermilab’s Short Baseline Neutrino Program and DUNE. I will give a broad overview of what could be gained with these capabilities. Then, I will provide concrete physics opportunities that are enabled by LArTPCs, including measuring the CP violation phase with atmospheric neutrinos, searching for light dark matter, and performing precision electroweak physics measurements. 
Thursday 4 February 2021, 11:00 at APC, bibliothèque du LPTHE, tour 1314, 4eme étage  SEMDARBOUX (Séminaire Darboux  physique théorique et mathématiques)  hepth 



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