Podcasts about Abelian

Lords * Daniel * https://www.cocoongame.com/ * https://kbones.itch.io/dorks * Alexander Topics: * Octopus dreams * Perception of memories. Why does actual recency and percieved recency often seem so at odds * Hike on 58 * https://www.poetryfoundation.org/poems/45087/sonnet-18-shall-i-compare-thee-to-a-summers-day * World of Warcraft over the years / WoW Hardcore Mode * The highest honor you can receive in mathematics is to have your name uncapitalized. * Polywater * My brain is polluted by trochaic trimeter recognition Microtopics: * Preventative care. * COVID lucky streaks. * Being able to go to the ER. * How to spell Cocoon. * Moth guys carrying orbs on their backs. * Boss battles that you wouldn't expect. * Wilford Brimley's agelessness. * Octopus nightmares. * The octopus equivalent of rapid eye movement. * Meeting sapient crows and asking them whether Y or Z should be up. * Which memories stick better. * Perception of time when you have a routine vs. when you don't. * Arranging your life to maximize perceived lifespan. * Different ways to have an adventure. * Shooby doooby doggie. * A sports rule that sounds like a 17776 plot point * Why the Bob Emergency is an emergency. * The best quarterbacks getting stuck in an endless hike and football ending forever. * The one person who hasn't played Frog Fractions but just listens to Topic Lords because they like topics so much. * Summer's lease. * Reading a poem aloud without knowing what "ow'st" means or how to pronounce it. * Words that used to rhyme but don't anymore. * Meter recognize meter. * Writing all your sonnets during COVID lockdown. * A poem about a dude that Shakespeare is not in love with. * Woe is me, etc. * Piss Jugman vs Piss Jugm'n. * Making phonetic reforms that don't take. * Smoothing off any rough edges or peculiarities. * Permadeath taking inspiration from real life. * A fun thing that you wouldn't have expected to see. * Enjoying spending time in the world. * Hold the W key and cruise through it. * The difference between wanting something vs. liking it. * Abelian. * The opposite of how you would think honor works. * Great honors: brands hate them! * Whether to capitalize "lynchian," "kafkaesque" or "quixotic" * Eternal abstract universal objects. * Teaching truck drivers where to put their piss jugs. * The highest honor Piss Jugman can receive. * The surname Piss. * What is the average Piss lifespan? * A real life Bobby Tables moment. * The Polywater Gap. * Water that scientists have sweated in. * Buying a can of Soviet Scientist Sweat in a Japanese vending machine. * Polyester intoxication. * Liquids with a lower freezing temperature than water. * The Polywater Doodle. * A metabolism described by Richard Feynman. * Brain Pollution. * The particular better of the first line of Aqualung by Jethro Tull. * Singing "parallelipiped" to the tune of Aqualung. * Hearing random phrases in your life. * Spelling "yogurt" backwards. * Trying to understand the New York Times' effect on man. * A killer rap album based on alliteration rather than rhyming. * Poetry that rhymes on the second to last syllable rather than the last. * The baffling cosmology of Butter Dorks.

1. Abelian Group: Actual Definition: An Abelian group, named after Niels Henrik Abel, is a group in which the binary operation is commutative, meaning that for all elements a and b in the group, a * b = b * a. Etymological Definition and Derivation: The term "Abelian" pays homage to the Norwegian mathematician Niels Henrik Abel, who made significant contributions to the theory of equations and group theory. The word "Abelian" is derived from the Latin word "Abelius," signifying Abel's enduring legacy. 2. Euclidean Geometry: Actual Definition: Euclidean geometry, introduced by the ancient Greek mathematician Euclid, is a branch of mathematics that deals with properties, relationships, and measurements of points, lines, angles, and surfaces in the plane and space, based on Euclid's five postulates. Etymological Definition and Derivation: "Euclidean" honors the legendary Greek mathematician Euclid, a beacon of geometrical elucidation. Rooted in the Greek term "Euclides," it resonates with the man's enduring dedication to the exploration of space. 3. Calculus: Actual Definition: Calculus is a branch of mathematics that explores the concepts of limits, derivatives, integrals, and infinite series, enabling the analysis of change and accumulation in various contexts. Etymological Definition and Derivation: "Calculus" emerges from the Latin "calculus," a diminutive of "calx," meaning a small stone used in counting and calculations. It was birthed by minds like Newton and Leibniz, who sculpted this art of calculation to harness the elusive infinitesimal. 4. Topology: Actual Definition: Topology is a field of mathematics that examines the properties of space that are preserved under continuous deformations, including concepts like continuity, convergence, compactness, and connectedness. Etymological Definition and Derivation: "Topology" emerges from the Greek roots "topos" (place) and "logos" (study), a testament to the exploration of spatial relations. Its true essence resides in the intimate scrutiny of shapes' essence beyond rigid measurements. 5. Eigenvalue: Actual Definition: In linear algebra, an eigenvalue of a matrix represents a scalar value that characterizes how a matrix transforms a vector, with the vector only scaling by the eigenvalue during the transformation. Etymological Definition and Derivation: "Eigenvalue" springs from the German "eigen," meaning inherent or characteristic, and "value." It encapsulates the distinct nature of values that a matrix uniquely possesses, much like a signature of its intrinsic behavior. 6. Homomorphism: Actual Definition: A homomorphism is a structure-preserving map between two algebraic structures, such as groups, rings, or vector spaces, that preserves the operations and relationships between elements. Etymological Definition and Derivation: "Homomorphism" finds its roots in the Greek "homos" (same) and "morphē" (form). This term embodies the lofty concept of maintaining similarity, preserving the integrity of structures across mathematical realms. 7. Fractal: Actual Definition: A fractal is a complex geometric shape or pattern that displays self-similarity at various scales, exhibiting intricate detail regardless of the level of magnification. Etymological Definition and Derivation: "Fractal" derives from the Latin "fractus," meaning broken or fractured. Coined by Benoît B. Mandelbrot, this term encapsulates the enigmatic beauty of structures that break free from the linear constraints of Euclidean space. --- Support this podcast: https://podcasters.spotify.com/pod/show/liam-connerly/support

Want to live 20 percent longer? Well, it may be possible in the future thanks to a new discovery. A life-extending mutation has been found in mice, and the team explains how its benefits can be transferred by transplanting blood stem cells. But will it work in humans?Cows' burps are a big problem for global warming - but could kangaroo poo be the solution? We hear about a novel new idea to replace the bacteria in cows' stomachs.A special kind of particle that can remember its past has been created using a quantum computer. The team explains the mind-bending qualities of this non-Abelian anyon, and how its creation could serve as a building block for advanced quantum computers.A new study has linked irregular sleeping patterns with an increased risk of death. The team finds out what's going on.Climate change may have broken a link between desert grasslands and the Pacific Ocean. We learn how this severed connection is impacting biodiversity in North America's Chihuahuan desert.On the pod are Chelsea Whyte, Sam Wong, Michael Le Page, James Dinneen, Alexandra Thompson and Alex Wilkins. To read about these subjects and much more, you can subscribe to New Scientist magazine at newscientist.com.Events and discount codes:newscientist.com/wondersofspace Hosted on Acast. See acast.com/privacy for more information.

Événements passésQuandela LOQathon des 7, 8 et 9 novembre 2022. Un hackathon organisé à Jussieu, en partenariat avec QICS, le hub quantique de Sorbonne Université, OVHcloud et le GENCI. Le 8 novembre avait lieu le lancement de EQSI, l'European Quantum Software Institute. https://www.quantum.amsterdam/launch-of-eqsi-european-quantum-software-institute-in-paris/OVHcloud EcoEx On Stage à l'Olympia. Le Summit du cloud provider avec 30 minutes dédiées au Quantique illustré par une interview enregistrée d'Alain Aspect suivie d'un panel Maud Vinet (SiQuance), Valérian Giesz (Quandela) et Christophe Legrand (Pasqal). Octave Klaba (fondateur) et Michel Paulin (DG) ont affirmé l'engagement d'OVHcloud autour du quantique. https://ecoexonstage.ovhcloud.com/en/ à 1h20 dans le replayAutre initiative en Allemagne, lancée et soutenue plus directement par le gouvernent allemand (Germany's Ministry of Economic Affairs and Climate Action, BMWK), autour de Ionoshttps://thequantuminsider.com/2022/11/14/germany-to-create-its-first-quantum-computing-business-cloud/Conférence Innovacs, le 24 novembre : « Scénarisez votre futur » sur le quantique, organisé par le groupement de recherche INNOVACS en sciences sociales de l'innovation.https://my.weezevent.com/soiree-ateliers-design-fiction.https://www.oezratty.net/Files/Work/Olivier%20Ezratty%20Design%20Fiction%20Quantique%20Nov2022.pptxJournée Quantique Minalogic du 4 octobre 2022https://www.youtube.com/playlist?list=PLYkgljOcCgszPUSHLTpXHnKlUAKS0ZFfiWorld Quantum Congress à Washington DC Village français avec Pasqal, Quandela, Alice&Bob et Siquance.https://www.quantum.gov/the-united-states-and-france-sign-joint-statement-to-enhance-cooperation-on-quantum/Événements à venirIEDM avec Maud Vinet « Enabling full fault tolerant quantum computing with silicon based VLSI technologies »https://www.ieee-iedm.org/program-overviewQ2B de Qc-Ware aux USA à Santa Clara dans la Silicon Valley.https://q2b.qcware.com/2022-conferences/silicon-valley/Conférence GDR RO sur la recherche opérationnelle à l'Université de Technologie de Troyes du 17 au 21 avril 2023. “Emerging optimization methods: from metaheuristics to quantum approaches”.https://perso.isima.fr/~lacomme/GT2L/EUME_JE/EUME_Joint_Event.phpÉvénement international avec une formation sur le calcul quantique (tutorials and practical work on quantum computing for optimization) lance par les groupes de travail EUME (Europe) et GT ROQ (France). StartupsLe 29 novembre 2022 avait lieu à Grenoble une conférence de presse pour l'annonce de la création de Siquance, la startup lancée par Maud Vinet, Tristan Meunier et François Perruchot. https://www.siquance.com/Visite de PasqalSee Quantum Feature Maps for Graph Machine Learning on a Neutral Atom Quantum Processor by Boris Albrecht, Loic Henriet et al, November 2022 (19 pages) présenté dans https://medium.com/pasqal-io/predicting-toxicity-with-qubits-c9dd2517df59. Quandela communique sur la mise en route de son premier calculateur quantique dans le cloud. Leur logiciel Perceval est disponible dans le cloud via OVHcloud pour accéder aussi bien à 12 qubits ainsi qu'à de l'émulation classique.https://www.quantum-inspire.com/https://www.quandela.com/wp-content/uploads/2022/11/Quandela-The-first-European-quantum-computer-on-the-cloud-developed-by-Quandela.pdfXanadu lève $100MScienceVisite de l'IRIG à Grenoble.https://thequantuminsider.com/2022/11/10/nqcc-appoints-professor-elham-kashefi-as-chief-scientist/ et … déjeuner avec elle le 8 Annonce d'IBM Osprey et de 433 qubits. https://www.oezratty.net/wordpress/2022/assessing-ibm-osprey-quantum-computer/.Une tribune de Xavier Vasquez d'IBM : https://www.zdnet.fr/actualites/la-decennie-quantique-avance-encore-plus-vite-que-prevu-39950318.htmLa Chine de son côté à 121 qubits supraconducteursDigital simulation of non-Abelian anyons with 68 programmable superconducting qubits by Shibo Xu et al, November 2022 (27 pages).Microsoft Resource EstimatorAssessing requirements to scale to practical quantum advantage by Michael E. Beverland et al, Microsoft Research, November 2022 (41 pages).https://alice-bob.com/2022/11/17/alice-bob-tests-azure-quantum-resource-estimator-highlighting-the-need-for-fault-tolerant-qubits/Architecture de réseaux quantiquesEleni Diamanti et Iordanis Kerenidis ont publié un papier portant sur la simulation d'un réseau quantique urbain avec ressources d'intrication.Quantum City: simulation of a practical near-term metropolitan quantum network par Raja Yehia, Simon Neves, Eleni Diamanti et Iordanis Kerenidis, Sorbonne Université LIP6 and Université Paris Cité IRIF, Novembre 2022 (28 pages).Et dans le domaine, Tom Darras et Julien Laurat du LKB de l'Ecole Normale (et aussi cofondateurs de la startup WeLinQ avec Eleni Diamanti) ont publié un pré-print où ils décrivent un protocole de conversion de qubits photons entre leurs variantes à variables discrètes et continues, permettant d'établir des liaisons distantes entre ordinateurs quantiques.A quantum-bit encoding converter by Tom Darras, Julien Laurat et al, November 2022 (15 pages).Le wormhole de Googlehttps://www.quantamagazine.org/physicists-create-a-wormhole-using-a-quantum-computer-20221130/https://ai.googleblog.com/2022/11/making-traversable-wormhole-with.htmlhttps://www.nature.com/articles/s41586-022-05424-3https://twitter.com/skdh/status/1598175023067717632?s=49&t=RHEFuw_j2qSqJMmRQqrBWw 

Multi-messenger constraints on Abelian-Higgs cosmic string networks by Mark Hindmarsh et al. on Wednesday 12 October Nielsen-Olesen vortices in the Abelian-Higgs (AH) model are the simplest realisations of cosmic strings in a gauge field theory. Large-scale numerical solutions show that the dominant decay channel of a network of AH strings produced from random initial conditions is classical field radiation. However, they also show that with special initial conditions, loops of string can be created for which classical field radiation is suppressed, and which behave like Nambu-Goto (NG) strings with a dominant decay channel into gravitational radiation. This indicates that cosmic strings are generically sources of both high-energy particles and gravitational waves. Here we adopt a simple parametrisation of the AH string network allowing for both particle and gravitational wave production, which sets the basis for a "multi-messenger" investigation of this model. We find that, in order to explain the NANOGrav detection of a possible gravitational wave background, while satisfying the constraint on NG-like loop production from simulations and bounds from the cosmic microwave background, the tension of the AH string in Planck units $Gmu$ and the fraction of the NG-like loops $f_{rm NG}$ should satisfy $Gmu f_{rm NG}^{2.6} gtrsim 3.2times 10^{-13}$ at 95$%$ confidence. On the other hand, for such string tensions, constraints from the diffuse gamma-ray background (DGRB) indicate that more than 97$%$ of the total network energy should be converted to dark matter (DM) or dark radiation. We also consider joint constraints on the annihilation cross-section, the mass, and the relic abundance of DM produced by decays of strings. For example, for a DM mass of 500 GeV, the observed relic abundance can be explained by decaying AH strings that also account for the NANOGrav signal. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.06178v1

Pharming Your Career: #HowIRxoll Part 4: A Passion for Clinical Pharmacology - Dr. Grigor Abelien   Grigor Abelian's Bio: Dr. Abelian graduated as University Valedictorian from Philadelphia College of Pharmacy at University of the Sciences with Bachelor of Science in Pharmaceutical and Healthcare Studies and Doctor of Pharmacy degrees.   During pharmacy school, he augmented his didactic training through internships at multiple institutions including Johns Hopkins Hospital at Critical Care/Surgery Department of Pharmacy, Janssen Research & Development in Clinical Pharmacology and Global Trial Management, and United States Food and Drug Administration at Office of Health Informatics. He supported and led multiple research projects spanning from pharmaceutics development of Tegafur and its parent drug 5-Fluorouracil in the Colon Cancer setting at University of the Sciences, Alcohol Withdrawal Syndrome in the Surgical Intensive Care setting at Johns Hopkins Hospital, and Trauma Registry Validation in the Venous Thromboembolism Prevention setting at University of Pennsylvania Perelman School of Medicine Center for Clinical Epidemiology and Biostatistics. Upon graduation, he completed a joint Postdoctoral Fellowship in Clinical Pharmacology at University of Southern California and Allergan, plc where he supported and led clinical pharmacology drug development efforts in the CNS, GI, Ophthalmology, Immunology, and Dermatology therapeutic areas.   Currently, he serves as a Research Investigator in the Global Clinical Pharmacology and Pharmacometrics function at Bristol-Myers Squibb where he supports research and development in the Cardiovascular, Immunology, and Oncology therapeutic areas. His core discipline interests include translational and precision medicine, pharmacogenomics, and model-based drug development.   In his spare time, he enjoys several sports including weight training, snowboarding, professional and pick-up football, soccer, basketball, and tennis in addition to traveling, hiking, and stock market investing.   LinkedIn: https://www.linkedin.com/in/grigor-abelian-pharmd-938a39bb/  See omnystudio.com/listener for privacy information.

In this lecture, Prof. Liu continues discussion of physics of D-branes, including low energy effective action, tension of D-branes, low energy effective theory of multiple coincidental D-branes, which are described by a non-Abelian gauge theory.

In the first part of this lecture, Prof. Liu explains physical motivation behind the holographic principle, and a formulation of the principle. In the second part, he starts a new topic on the large N limit of a non-Abelian gauge theory.

In this thesis we study the geometry and the low-energy effective physics associated with Abelian gauge groups in F-theory compactifications. To construct suitable torus-fibered Calabi-Yau manifolds, we employ the framework of toric geometry. By identifying appropriate building blocks of Calabi-Yau manifolds that can be studied independently, we devise a method to engineer large numbers of manifolds that give rise to a specified gauge group and achieve a partial classification of toric gauge groups. Extending our analysis from gauge groups to matter spectra, we prove that the matter content of the most commonly studied F-theory set-ups is rather constrained. To circumvent such limitations, we introduce an algorithm to analyze torus-fibrations defined as complete intersections and present several novel kinds of F-theory compactifications. Finally, we show how torus-fibrations without section are linked to fibrations with multiple sections through a network of successive geometric transitions. In order to investigate the low-energy effective physics resulting from our compactifications, we apply M- to F-theory duality. After determining the effective action of F-theory with Abelian gauge groups in six dimensions, we compare the loop-corrected Chern-Simons terms to topological quantities of the compactification manifold to read off the massless matter content. Under certain assumptions, we show that all gravitational and mixed anomalies are automatically canceled in F-theory. Furthermore, we compute the low-energy effective action of F-theory compactifications without section and suggest that the absence of a section signals the presence of an additional massive Abelian gauge field. Adjusting our analysis to four dimensions, we show that remnants of this massive gauge field survive as discrete symmetries that impose selection rules on the Yukawa couplings of the effective theory.

We consider the geometric and non-geometric faces of closed string vacua arising by T-duality from principal torus bundles with constant H-flux and pay attention to their double phase space description encompassing all toroidal coordinates, momenta and their dual on equal footing. We construct a star-product algebra on functions in phase space that is manifestly duality invariant and substitutes for canonical quantization. The 3-cocycles of the Abelian group of translations in double phase space are seen to account for non-associativity of the star-product. We also provide alternative cohomological descriptions of non-associativity and draw analogies with the quantization of point-particles in the field of a Dirac monopole or other distributions of magnetic charge. The magnetic field analogue of the R-flux string model is provided by a constant uniform distribution of magnetic charge in space and non-associativity manifests as breaking of angular symmetry. The Poincare vector comes to rescue angular symmetry as well as associativity and also allow for quantization in terms of operators and Hilbert space only in the case of charged particles moving in the field of a single magnetic monopole.

Uranga, A (IFT-UAM/CSIC) Thursday 28 June 2012, 15:10-15:45

Sezgin, E (Texas A&M University) Tuesday 22 May 2012, 11:00-12:00

Matsuo, Y (University of Tokyo) Tuesday 06 March 2012, 11:30-12:30

Alexeev, V (Georgia) Thursday 13 January 2011, 15:30-16:30

Goertz , U (Duisberg/Essen) Thursday 03 March 2011, 14:00-15:00

Lopez Martin, C (Salamanca) Thursday 20 January 2011, 15:30-16:30

Matter, M (Université de Genève) Thursday 29 July 2010, 17:30-17:45

This thesis is devoted to exploit strong correlations among ultracold atoms in order to create novel, exotic quantum states. In the first two chapters, we devise dynamical out-of-equilibrium preparation schemes which lead to intriguing final states. First of all, we propose to create the elusive supersolid state via a quantum quench protocol. Supersolids – quantum hybrids exhibiting both superflow and solidity – have been envisioned long ago, but have not been demonstrated in experiment so far. Our proposal to create a supersolid state is perfectly accessible with current technology and may clear the way to the experimental observation of supersolidity. Another out-of-equilibrium preparation scheme is discussed in the second chapter, giving rise to novel Cooper pairs of bosons. Ordinarily, Cooper pairs are composed of fermions – not so in our setup! We show that a Mott state of local bosonic Bell pairs can evolve into a Cooper-paired state of bosons, where the size of the pairs becomes macroscopic. This state can be prepared via a quick, diabatic ramp from the Mott into the superfluid regime. Furthermore, we propose to use bosons featuring conditional-hopping amplitudes in order to create Abelian anyons in one-dimensional optical lattices. We derive an exact mapping between anyons and bosons via a “fractional” Jordan-Wigner transformation. We suggest to employ a laser-assisted tunneling scheme to establish the many-particle state of “conditional-hopping bosons”, thus realizing a gas of Abelian anyons. The fractional statistics phase can be directly tuned by the lasers. The realization of non-Abelian anyons would be especially delightful, due to their significance in topological quantum computation schemes. We propose to employ strongly correlated bosons in one-dimensional optical lattices to create the Pfaffian state – which is known to host non-Abelian anyons as elementary excitations. In this setup, three-body correlations are required to dominate the system, which we model by on-site interactions of atoms with diatomic molecules. Finally, we use strong correlations in one-dimensional systems to create the effect of spin-charge separation, as formulated theoretically first in 1968. For a model of two-component bosons we compute the effective mass of a spin-flip excitation via Bethe Ansatz. In the strongly correlated regime, we show that the effective mass reaches the total mass of all particles in the system. The spin wave thus travels much more slowly than the density wave, giving rise to a strong spin-charge separation.

The concept of self-organized criticality was proposed as an explanation for the occurrence of fractal structures in diverse natural phenomena. Roughly speaking the idea behind self-organized criticality is that a dynamic drives a system towards a stationary state that is characterized by power law correlations in space and time. We study two of the most famous models that were introduced as models exhibiting self-organized criticality. The first of them is the forest fire model. In a forest fire model each site (vertex) of a graph is either vacant or occupied by a tree. Vacant sites get occupied according to independent rate 1 Poisson processes. Independently, at each sites ignition (by lightning) occurs according to independent Poisson processes that have rate Lambda>0. When a site is ignited its whole cluster of occupied sites becomes vacant instantaneously. It is known that infinite volume forest fire processes exist for all ignition rates Lambda>0. The proof of existence is rather abstract, and does not imply uniqueness. Nor does the construction answer the question whether infinite volume forest fire processes are measurable with respect to their driving Poisson processes. Motivated by these questions, we show the almost sure infinite volume convergence for forest fire models with respect to their driving Poisson processes. Our proof is quite general and covers all graphs with bounded vertex, all positive ignition rates Lambda>0, and a quite large set of initial configurations. One of the main ingredients of the proof is an estimate for the decay of the cluster size distribution in a forest fire model. For Gamma>0, we study the probability that the cluster at site x and time t>=Gamma is larger than m, conditioned on the configuration of some further clusters at time t. We show that as m tends to infinity, this conditional probability decays to zero. The convergence is uniform in the choice of the site x, the time t, and the configuration of the further clusters we condition on. Being a consequence of almost sure infinite volume convergence, we obtain uniqueness and measurability with respect to the driving Poisson processes, and the Markov property. The second model in focus is the Abelian sandpile model. Let Lambda be a finite subset of the two-dimensional integer lattice. We consider the following sandpile model on Lambda: each vertex in Lambda contains a sandpile with a height between one and four sand grains. At discrete times, we choose a site v in Lambda randomly and add a sand grain at the site v. If after adding the sand grain the height at the site v is strictly larger than four, then the site topples. That is, four sand grains leave the site v, and each distance-one-neighbour of v gets one of these grains. If after toppling the site v there are other sites with a height strictly larger than four, we continue by toppling these sites until we obtain a configuration where all sites have a height between one and four. We study the scaling limit for the height one field in such a sandpile model. More precisely, we identify the scaling limit for the covariance of having height one at two macroscopically distant sites. We show that this scaling limit is conformally covariant. Furthermore, we show a central limit theorem for the sandpile height one field. Our results are based on a representation of the height one joint intensities that is close to a block-determinantal structure.

Gauge-boson pair-production processes with an additional hadronic jet are of particular interest as background to Higgs and new-physics searches at hadron colliders. Moreover, they enable---besides genuine gauge-boson pair production---a direct analysis of the non-Abelian gauge-boson self-interactions in the electroweak sector. In this work we provide precision calculations for the processes pp->VV+jet+X. In detail, corrections to WW+jet, ZZ+jet, and WZ+jet production are evaluated at next-to-leading-order in the strong coupling (NLO QCD). Particular care has to be taken when treating the infrared singularities arising in the virtual and real corrections. The FormCalc/LoopTools package is applied for the virtual corrections, where dimensionally regularized infrared-divergent integrals are added to the FF library which is used for the regular ones. The real-emission matrix elements are evaluated in terms of helicity amplitudes in the Weyl--van-der-Waerden formalism. The Catani--Seymour dipole subtraction formalism mediates the cancellation of infrared divergences between the two contributions. To perform the numerical integration a multi-channel Monte Carlo integrator is written in C++, which is designed to meet the requirements of integrating cross sections in the dipole subtraction formalism. For all gauge-boson assignments, the NLO QCD corrections significantly stabilize the artificial dependence of the leading-order (LO) cross sections on renormalization and factorization scales for Tevatron. For LHC, however, only a modest reduction of the scale dependence results unless a veto on a second hard jet is applied. Beyond investigating the production processes, leptonic decays of the gauge bosons are considered. To this end, a full amplitude calculation including resonant and non-resonant contributions to the leptonic final states, a simple narrow-width approximation (NWA), and an improved version of the NWA that takes into account spin correlations are performed at LO. Comparing these approaches the improved NWA turns out to deliver an appropriate approximation to the decays at a reasonable level of accuracy. Thus, an NLO QCD calculation to VV+jet including leptonic decays is performed in the framework of the improved NWA. Several results on differential cross sections for quantities of the jet and the decay leptons are presented. For WW+jet, we discuss both proton--proton collisions at LHC and proton--antiproton collisions at Tevatron. For WZ+jet and ZZ+jet, however, the cross sections at Tevatron are too small, so only results for LHC are presented. The Monte Carlo generator developed in this thesis can be used as a tool in data analysis at LHC and Tevatron.

We study the weak convergence (in the high-frequency limit) of the frequency components associated with Gaussian-subordinated, spherical and isotropic random fields. In particular, we provide conditions for asymptotic Gaussianity and we establish a new connection with random walks on the the dual of SO(3), which mirrors analogous results previously established for fields defined on Abelian groups. Our work is motivated by applications to cosmological data analysis, and specifically by the probabilistic modelling and the statistical nalysis of the Cosmic Microwave Background radiation, which is currently at the frontier of physical research. To obtain our main results, we prove several fine estimates involving convolutions of the so-called Clebsch-Gordan coefficients (which are elements of unitary matrices connecting reducible representations of SO(3)); this allows to intepret most of our asymptotic conditions in terms of coupling of angular momenta in a quantum mechanical system. Part of the proofs are based on recently established criteria for the weak convergence of multiple Wiener-Itô integrals. This is a joint paper by Domenico Marinucci (Rome "Tor Vergata") and Giovanni Peccati (Paris VI). Domenico MARINUCCI Document associé : support de présentation : http://epi.univ-paris1.fr/servlet/com.univ.collaboratif.utils.LectureFichiergw?CODE_FICHIER=1207750104939 (pdf) Ecouter l'intervention : Bande son disponible au format mp3 Durée : 57 mn

As of now, string theory is the best candidate for a theory of quantum gravity. Since it is anomaly–free only in ten space-time dimensions, the six surplus spatial dimensions must be compactified. This thesis is concerned with the geometry of toroidal orbifolds and their applications in string theory. An orbifold is the quotient of a smooth manifold by a discrete group. In the present thesis, we restrict ourselves to orbifolds of the form T^6 /Z_N or T^6 /Z_N × Z_M . These so–called toroidal orbifolds are particularly popular as compactification manifolds in string theory. They present a good compromise between a trivial compactification manifold, such as the T^6 and one which is so complicated that explicit calculations are nearly impossible, which unfortunately is the case for many if not most Calabi–Yau manifolds. At the fixed points of the discrete group which is divided out, the orbifold develops quotient singularities. By resolving these singularities via blow–ups, one arrives at a smooth Calabi–Yau manifold. The systematic method to do so is explained in detail. Also the transition to the Orientifold quotient is explained. In string theory, toroidal orbifolds are popular because they combine the advantages of calculability and of incorporating many features of the standard model, such as non-Abelian gauge groups, chiral fermions and family repetition. In the second part of this thesis, applications in string phenomenology are discussed. The applications belong to the framework of compactifications with fluxes in type IIB string theory. Flux compactifications on the one hand provide a mechanism for supersymmetry breaking. One the other hand, they generically stabilize at least part of the geometric moduli. The geometric moduli, i.e. the deformation parameters of the compactification manifold correspond to massless scalar fields in the low energy effective theory. Since such massless fields are in conflict with experiment, mechanisms which generate a potential for them and like this fix the moduli to specific values must be investigated. After some preliminaries, two main examples are discussed. The first belongs to the category of model building, where concrete models with realistic properties are investigated. A brane model compactified on T^6 /Z_2 × Z_2 is discussed. The flux-induced soft supersymmetry breakingparameters are worked out explicitly. The second example belongs to the sub ject of moduli stabilization along the lines of the proposal of Kachru, Kallosh, Linde and Trivedi (KKLT). Here, in addition to the background fluxes, non-perturbative effects serve to stabilize all moduli. In a second step, a meta-stable vacuum with a small positive cosmological constant is achieved. Orientifold models which result from resolutions of toroidal orbifolds are discussed as possible candidate models for an explicit realization of the KKLT proposal. The appendix collects the technical details for all commonly used toroidal orbifolds and constitutes a reference book for these models.

Abstract: A quiver is simply a directed graph. By a representation of a quiver we mean a collection of vector spaces indexed by the nodes of the graph, together with linear maps corresponding to the arrows of the graph. We will introduce the notions of simple and indecomposable representations of a quiver (which may be considered part of the Abelian category structure of quiver representations). Gabriel asked which quivers have "finite representation type", that is, which quivers have finitely many indecomposables, and discovered a beautiful connection to Lie theory: The quivers with this property are precisely those whose underlying undirected graph is the Dynkin diagram of a Lie algebra. Moreover the indecomposable objects themselves are indexed by the roots of the associated Lie algebra. We will give an account of this theorem.