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 Upcoming Seminars [ scheduler view ]

 Thursday 25 February 2021, 11:00 at IHP, Zoom ( https://zoom.us/j/97507124810 pwd 1234 ) RENC-THEO (Rencontres Théoriciennes) hep-th Yu-Tin Huang ( National Taiwan University ) An EFT/CFT Duality": from the modular-hedron to the EFT-hedron Abstract: In this talk we will show that the space of consistent EFTs and 2D CFTs are governed by the same geometry. For the former, the theory space stems from a four-point S-matrix that is consistent with having a crossing symmetric unitary and Lorentz invariant UV completion, while the latter is deduced from modular invariant torus partition functions. We will show that in both cases, the space is given by a product geometry of convex hull of points on positive moment curves, intersecting with the subplane reflecting crossing/modular symmetry. We will provide evidence that a particular vertex of the intersecting geometry gives the extremal spectrum of the discretize (derivative expansion) bootstrap problem.

 Friday 26 February 2021, 11:00 at APC, https://u-paris.zoom.us/j/89740559438?pwd=OWE5eVBrelYrZXoyN21UcjRjRXVXdz09 APC-COLLOQUIUM (Colloquium de l'APC) astro-ph Michela Mapelli ( University of Padova ) Changing paradigms for binary black hole formation Abstract: The latest results from the LIGO-Virgo collaboration challenge the astrophysical scenarios of black hole formation. In this talk, I will discuss the main astrophysical formation channels of binary black holes. On the one hand, models of stellar evolution and pair instability supernovae suggest a gap in the mass spectrum of black holes between ~60 and ~120 Msun. The boundaries of this gap depend on stellar rotation and on the efficiency of envelope removal. On the other hand, extreme dynamical processes in dense star clusters can fill the mass gap, via multiple stellar collisions, dynamical exchanges and hierarchical mergers. Based on a data-driven model, I will discuss the merger history of dynamical versus isolated binary compact objects across cosmic time, and its dependence on the cosmic star formation rate and the stellar metallicity.

 Friday 26 February 2021, 14:00 at LPTM, St Martin Batiment E SOUTEN-TH (Soutenance de thèse) cond-mat Venkateswarlu Somepalli ( LPTM, CY CPU Cergy ) Electronic properties of two-dimensionalheterostructures based on graphene andtransition metal dichalcogenides. Abstract: After the first demonstration of graphene, 2D materials have attracted tremen-dous attention in the electronic devices community. Graphene was regarded as a promising material for electronics due to its extremely high carrier mobility. However, graphene is a semi-metal that does not have a band gap in its inherent form, which makes it inappropriate for switching devices in digital logic circuits.More recently new class of 2D semiconducting materials, such as Transition Metal Dichalcogenides (TMDs), have been found, and it has been shown that stacking layered materials to get heterostructures is a very powerful method to tailor their properties, mixing them, but also inducing new ones. In this context, this PhD thesis work focused on the electronic properties of monolayers of TMDs, graphene/TMDs bilayers, and twisted bilayers of TMDs. In order to study such a complex structures, we have combined the density functional theory (DFT) approaches and simplified tight-binding (TB) models.

 Monday 1 March 2021, 10:45 at LPTMC, On-line zoom seminar ( https://zoom.us/j/3863193200 ID de réunion : 386 319 3200 Code secret : 044816 ) SEM-LPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée) cond-mat.mes-hall Rémy Mosseri ( LPTMC ) Liquid crystal director fields in three-dimensional non-Euclidean geometries Abstract: This work investigates nematic liquid crystals in three-dimensional curved space, and determines which director deformation modes are compatible with each possible type of non-Euclidean geometry. Previous work by Sethna et al. [1] showed that double twist is frustrated in flat space , but can fit perfectly in the hypersphere. Here, we extend that work to all four deformation modes (splay, twist, bend, and biaxial splay) and all eight Thurston geometries [2]. Each pure mode of director deformation can fill space perfectly, for at least one type of geometry. This analysis shows the ideal structure of each deformation mode in curved space, which is frustrated by the requirements of flat space. [1] Sethna J. P., Wright D. C. and Mermin N. D., 1983 Phys. Rev. Lett. 51 467–70. [2] J.-F. Sadoc, R. Mosseri and J. Selinger, New Journal of Physics 22 (2020) 093036.

 Tuesday 2 March 2021, 14:00 at LPTHE, https://zoom.us/j/97404769748 LPTHE-PPH (Particle Physics at LPTHE) hep-ph Oscar Macias ( U. Amsterdam & IPMU Tokyo ) Searching for evidence of TeV-scale electron/positron acceleration by Millisecond Pulsars Abstract: Pulsars have long been predicted to be sources of electron/positron (e-e+) pairs. Highly energetic e-e+ in the wind regions, or inner magnetospheres of pulsars, and also when released into the interstellar medium, can inverse-Compton (IC) scatter ambient photons to very high energies. Recent HAWC observations of extended TeV-scale gamma-ray emission around Geminga and Monogem have provided indirect evidence for multi-TeV e-e+ acceleration in young pulsar nebulae. However, predicting and observing high energy gamma-ray emission from rotation-powered millisecond pulsars (MSPs) presents a number of challenges compared to that of the non-recycled pulsar population. During this talk, I will summarize these challenges, and present our recent exciting results where we find evidence for very high energy gamma ray emission from populations of MSPs residing in globular clusters of the Milky Way. I will further highlight the unique capabilities of the Cherenkov Telescope Array to detect the expected IC signal from a putative population of 10 to 50 thousand MSPs in the center of our Galaxy.

 Friday 5 March 2021, 11:00 at APC, https://u-paris.zoom.us/j/84776224570?pwd=ZWNLMEQ0bThsWGJuL0IvbnUxTEpxUT09 APC-COLLOQUIUM (Colloquium de l'APC) hep-th Mikhail Shaposhnikov ( EPFL Lausanne ) TBA Abstract: TBA

 Friday 5 March 2021, 14:00 at LPTENS, GoToMeeting ( https://www.gotomeet.me/LPENS-IF Code: 418-109-349 ) STR-LPT-ENS-HE (Séminaire commun LPTENS/LPTHE) hep-th Vassilis Papadopoulos ( LPENS ) Phases of Holographic Interfaces Abstract: We compute the phase diagram of the simplest holographic bottom-up model of conformal interfaces. The model consists of a thin domain wall between three-dimensional Anti-de Sitter (AdS) vacua, anchored on a boundary circle. We distinguish five phases depending on the existence of a black hole, the intersection of its horizon with the wall, and the fate of inertial observers. We show that, like the Hawking-Page phase transition, the capture of the wall by the horizon is also a first order transition and comment on its field-theory interpretation. The static solutions of the domain-wall equations include gravitational avatars of the Faraday cage, black holes with negative specific heat, and an intriguing phenomenon of suspended vacuum bubbles corresponding to an exotic interface/anti-interface fusion. Part of our analysis overlaps with recent work by Simidzija and Van Raamsdonk but the interpretation is different.

 Monday 15 March 2021, 11:00 at IPHT, (voir dans annonce) IPHT-PHM (Séminaire de physique mathématique) math-ph Peter Forrester ( Melbourne University ) Properties and applications of the structure function in random matrix theory Abstract: The structure function, also known as the spectral form factor, is fundamental to the bulk scaled state in random matrix theory. In the case of the circular $\beta$ ensemble, we discuss a functional equation satisfied by this quantity, which relates $\beta$ to $4/ \beta$, its small $k$ expansion which has polynomial coefficients in $\beta/2$, and properties of these polynomials. A recent study of the structure function for even $\beta$ using linear differential equations of degree $\beta 1$ allows the 10th order polynomial to be computed, and also provides extra insight into the functional forms for the classical values $\beta$ = 1,2 and 4. For a non-translationally invariant system, such as the Gaussian and Laguerre ensembles, the structure function is closely related to the average of the quadratic statistic $|\sum_{j=1}^N e^{i k \lambda_j}|^2$. It has attracted interest in recent studies of the SYK model and many body quantum chaos through its graphical shape, known as dip-ramp-plateau. A result of Brézin and Hikami from 1997 evaluates this for the Gaussian unitary ensemble. It is shown that an analogous result can be obtained for the Laguerre unitary ensemble, and implications are discussed.\\ \\ The seminar is online only. \\ Internet link to be collected from the Organizer: vincent.pasquier@ipht.fr

 Tuesday 13 April 2021, 16:00 at IHP, Seminar via zoom https://ijclab.zoom.us/j/94900481972 P^3 (Particle Physics in Paris) astro-ph|hep-ph|hep-th Géraldine Servant ( DESY and University of Hamburg ) TBA

 seminars All Next Week This Week Today Tomorrow Upcoming Within a Week from series All ACFTA APC APC-COLLOQUIUM APC-TH BH-TOP BI-COSMO-IHP BI-SEM-IHP BIOPHY-ENS-ESPCI BISEMINAIRE-MP COLLOQUIUM-ENS CONDMAT-ENS CONDMAT-THEO COSMO-P6 COURS COURS-FED COURS-IPHT COURS@IAP CPHT - PHDSEM CPHT PHYS MATH CPHT- BS CPHT-JOUR CPHT-LLR CPMC DISQUANT ESPCI-COLLOQUE ESPCI/PCT FCMP FORUM-ENS FOUNDPHYS GDT-MODSTO GQ GR-COSMO IAP-SEM IDRIS-SEM IHP-ALG IHP-NONEQ IHPSTRMATH IJCLAB-COSM IMJ-AA IMJ-AUT IMJ-CHE IMJ-EAA IMJ-REP IMP-MATH-PHYS INST-ETE IPHT-DAP IPHT-GEN IPHT-HEP IPHT-MAT IPHT-PHM IPHT-SEM IPHT-STA IPN-X IPNO-DR JOUR-CLUB LP(N/T)HE LPENS-ACE LPENS-MDQ LPNHE LPS-MAGN LPS-MAT-MOL LPS-VULG LPS/ENS LPT-GEN LPT-LPTMS LPT-MAG LPT-PHYSMATH LPT-PTH LPTENS-HE LPTHE-DOC LPTHE-PPH LPTMS LPT_STAT MAG-SUPRA MAT-COND-GEN MATH-IHES MECA-STAT MOTFEYN MSC NUC-THEO PART-PHYS PHEN-PART PHYS-ESPCI PLATEAU PMMH PT-IHES P^3 RENC-THEO RENORMALISATION S-LPTENS SAMM SCOPI SEM-BESSON SEM-CPHT SEM-CSNSM SEM-DARBOUX SEM-EXCEP SEM-FED SEM-GRECO SEM-GRECO-IAP SEM-IBPC SEM-ILP SEM-INFOR SEM-INSP SEM-LAL SEM-LKB SEM-LLR SEM-LPT SEM-LPTENS SEM-LPTHE SEM-LPTM-UCP SEM-LPTMC SEM-LPTMS SEM-LUTH SEM-PHYS-ENS SEM-PMMH SEM-POINCA SEM-UPR5 SOUTEN-HDR SOUTEN-TH SPEC-LARSIM SPEC-SEM STR-LPT-ENS-HE STR-LPTHE STRINT TH-JEUX TH-MAT-COND TRANSPORT TRI-SEMINAIRE WG-EXPTH-LPN/THE WORK-CONF at institute All APC CDF CITEU CPHT CSNSM CURIE DPT-PHYS-ENS ENPC ESPCI ESPCI/UPR5 GRETIA IAP IBPC IDRIS IHES IHP IJCLAB IM-JUSSIEU-PRG IMPMC INSP IPHT IPN LAL LARSIM LKB LLR LMPT LPA LPENS LPMA LPNHE LPNHE-GR-TH LPP LPS-ORSAY LPS/ENS LPT LPTENS LPTHE LPTM LPTMC LPTMS LUTH MSC OBSPARIS PCT/ESPCI PMMH SAMM SPEC UPMC in subject All CoRR -- Computing Research Repository CoRR.AI -- Artificial Intelligence CoRR.AR -- Architecture CoRR.CC -- Computational Complexity CoRR.CE -- Computational Engineering CoRR.CG -- Computational Geometry CoRR.CL -- Computation and Language CoRR.CR -- Cryptography and Security CoRR.CV -- Computer Vision and Pattern Recognition CoRR.CY -- Computers and Society CoRR.DB -- Databases CoRR.DC -- Distributed, Parallel, and Cluster Computing CoRR.DL -- Digital Libraries CoRR.DM -- Discrete Mathematics CoRR.DS -- Data Structures and Algorithms CoRR.GL -- General Literature CoRR.GR -- Graphics CoRR.GT -- Computer Science and Game Theory CoRR.HC -- Human-Computer Interaction CoRR.IR -- Information Retrieva CoRR.IT -- Information Theory CoRR.LG -- Learning CoRR.LO -- Logic in Computer Science CoRR.MA -- Multiagent Systems CoRR.MM -- Multimedia; CoRR.MS -- Mathematical Software CoRR.NA -- Numerical Analysis CoRR.NE -- Neural and Evolutionary Computing CoRR.NI -- Networking and Internet Architecture CoRR.OH -- Other CoRR.OS -- Operating Systems CoRR.PF -- Performance CoRR.PL -- Programming Languages CoRR.RO -- Robotics CoRR.SC -- Symbolic Computation CoRR.SD -- Sound CoRR.SE -- Software Engineering astro-ph -- Astrophysics cond-mat -- Condensed Matter cond-mat.dis-nn -- Disordered Sys. and Neural Networks cond-mat.mes-hall -- Mesoscopic Sys. and Q.Hall Effect cond-mat.mtrl-sci -- Materials Science cond-mat.other -- Other cond-mat.soft -- Soft Condensed Matter cond-mat.stat-mech -- Statistical Mechanics cond-mat.str-el -- Strongly Correlated Electrons cond-mat.supr-con -- Superconductivity gr-qc -- General Relativity and Quantum Cosmology hep-ex -- High Energy Physics - Experiment hep-lat -- High Energy Physics - Lattice hep-ph -- High Energy Physics - Phenomenology hep-th -- High Energy Physics - Theory math -- Mathematics math-ph -- Mathematical Physics math.AC -- Commutative Algebra math.AG -- Algebraic Geometry math.AP -- Analysis of PDEs math.AT -- Algebraic Topology math.CA -- Classical Analysis and ODEs math.CO -- Combinatorics math.CT -- Category Theory math.CV -- Complex Variables math.DG -- Differential Geometry math.DS -- Dynamical Systems math.FA -- Functional Analysis math.GM -- General Mathematics math.GN -- General Topology math.GR -- Group Theory math.GT -- Geometric Topology math.HO -- History and Overview math.KT -- K-Theory and Homology math.LO -- Logic math.MG -- Metric Geometry math.MP -- Mathematical Physics math.NA -- Numerical Analysis math.NT -- Number Theory math.OA -- Operator Algebras math.OC -- Optimization and Control math.PR -- Probability math.QA -- Quantum Algebra math.RA -- Rings and Algebras math.RT -- Representation Theory math.SG -- Symplectic Geometry math.SP -- Spectral Theory math.ST -- Statistics nlin -- Nonlinear Sciences nlin.AO -- Adaptation and Self-Organizing Systems nlin.CD -- Cellular Automata and Lattice Gases nlin.CG -- Chaotic Dynamics nlin.PS -- Exactly Solvable and Integrable Systems nlin.SI -- Pattern Formation and Solitons nucl-ex -- Nuclear Experiment nucl-th -- Nuclear Theory physics -- Physics physics.acc-ph -- Accelerator Physics physics.ao-ph -- Atmospheric and Oceanic Physics physics.atm-clus -- Atomic and Molecular Clusters physics.atom-ph -- Atomic Physics physics.bio-ph -- Biological Physics physics.chem-ph -- Chemical Physics physics.class-ph -- Classical Physics physics.comp-ph -- Computational Physics physics.data-an -- Data Analysis physics.ed-ph -- Physics Education physics.flu-dyn -- Fluid Dynamics physics.gen-ph -- General Physics physics.geo-ph -- Geophysics physics.hist-ph -- History of Physics physics.ins-det -- Instrumentation and Detectors physics.med-ph -- Medical Physics physics.optics -- Optics physics.plasm-ph -- Plasma Physics physics.pop-ph -- Popular Physics physics.soc-ph -- Physics and Society physics.space-ph -- Space Physics q-bio -- Quantitative Biology qbio.BM -- Biomolecules qbio.CB -- Cell Behavior qbio.GN -- Genomics qbio.MN -- Molecular Networks qbio.NC -- Neurons and Cognition qbio.OT -- Other qbio.PE -- Populations and Evolution qbio.QM -- Quantitative Methods qbio.SC -- Subcellular Processes; Tissues and Organs qbio.TO -- Tissues and Organs quant-ph -- Quantum Physics with field Speaker Title Abstract Subject matching

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