Staff, Visiting Scientists and Graduate Students 2014
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Arxiv:1303.1406V1 [Astro-Ph.HE] 6 Mar 2013 the flux of Gamma-Rays from Dark Matter Annihilation Takes a Surprisingly Simple Form 2
4th Fermi Symposium : Monterey, CA : 28 Oct-2 Nov 2012 1 The VERITAS Dark Matter Program Alex Geringer-Sameth∗ for the VERITAS Collaboration Department of Physics, Brown University, 182 Hope St., Providence, RI 02912 The VERITAS array of Cherenkov telescopes, designed for the detection of gamma-rays in the 100 GeV-10 TeV energy range, performs dark matter searches over a wide variety of targets. VERITAS continues to carry out focused observations of dwarf spheroidal galaxies in the Local Group, of the Milky Way galactic center, and of Fermi-LAT unidentified sources. This report presents our extensive observations of these targets, new statistical techniques, and current constraints on dark matter particle physics derived from these observations. 1. Introduction Earth's atmosphere as a target for high-energy cosmic particles. An incoming gamma-ray may interact in the The characterization of dark matter beyond its Earth's atmosphere, initiating a shower of secondary gravitational interactions is currently a central task particles that travel at speeds greater than the local of modern particle physics. A generic and well- (in air) speed of light. This entails the emission of motivated dark matter candidate is a weakly in- ultraviolet Cherenkov radiation. The four telescopes teracting massive particle (WIMP). Such particles of the VERITAS array capture images of the shower have masses in the GeV-TeV range and may inter- using this Cherenkov light. The images are analyzed act with the Standard Model through the weak force. to reconstruct the direction of the original particle as Searches for WIMPs are performed at particle accel- well as its energy. -
Supergravity and Its Legacy Prelude and the Play
Supergravity and its Legacy Prelude and the Play Sergio FERRARA (CERN – LNF INFN) Celebrating Supegravity at 40 CERN, June 24 2016 S. Ferrara - CERN, 2016 1 Supergravity as carved on the Iconic Wall at the «Simons Center for Geometry and Physics», Stony Brook S. Ferrara - CERN, 2016 2 Prelude S. Ferrara - CERN, 2016 3 In the early 1970s I was a staff member at the Frascati National Laboratories of CNEN (then the National Nuclear Energy Agency), and with my colleagues Aurelio Grillo and Giorgio Parisi we were investigating, under the leadership of Raoul Gatto (later Professor at the University of Geneva) the consequences of the application of “Conformal Invariance” to Quantum Field Theory (QFT), stimulated by the ongoing Experiments at SLAC where an unexpected Bjorken Scaling was observed in inclusive electron- proton Cross sections, which was suggesting a larger space-time symmetry in processes dominated by short distance physics. In parallel with Alexander Polyakov, at the time in the Soviet Union, we formulated in those days Conformal invariant Operator Product Expansions (OPE) and proposed the “Conformal Bootstrap” as a non-perturbative approach to QFT. S. Ferrara - CERN, 2016 4 Conformal Invariance, OPEs and Conformal Bootstrap has become again a fashionable subject in recent times, because of the introduction of efficient new methods to solve the “Bootstrap Equations” (Riccardo Rattazzi, Slava Rychkov, Erik Tonni, Alessandro Vichi), and mostly because of their role in the AdS/CFT correspondence. The latter, pioneered by Juan Maldacena, Edward Witten, Steve Gubser, Igor Klebanov and Polyakov, can be regarded, to some extent, as one of the great legacies of higher dimensional Supergravity. -
Ultraviolet Fixed Point Structure of Renormalizable Four-Fermion Theory in Less Than Four Dimensions*
160 Ultraviolet Fixed Point Structure of Renormalizable Four-Fermion Theory in Less Than Four Dimensions* Yoshio Kikukawa Department of Physics, Nagoya University, Nagoya 464-01,Japan Abstract We study the renormalization properties of the four-fermion theory in less than four dimen sions (D < 4) in 1/N expansion scheme. It is shown that /3 function of the bare coupling has a nontrivial ultraviolet fixed point with a large anomalous dimension ( 'Yti;.p = D - 2) in a similar manner to QED and gauged Nambu-Jona-Lasinio (NJL) model in ladder approximation. The anomalous dimension has no discontinuity across the fixed point in sharp contrast to gauged NJL model. The operator product expansion of the fermion mass function is also given. Introduction Recently the possibility that QED may have a nontrivial ultraviolet(UV) fixed point has been paid much attention from the viewpoints of "zero charge" problem in QED and raising condensate in technicolor model. Actually such a possibility was pointed out in ladder approximation in which the cutoff Schwinger-Dyson equation for the fermion self-energy possesses a spontaneous-chiral symmetry-breaking solution for the bare coupling larger than a non-zero value ( ao =eij/ 411" > ?r/3 = ac)- We can make this solution finite by letting ao have a cutoff dependence in such a way that ao( I\) _,. ac + 0 (I\ - oo ), ac being identified as the critical point with scaling behavior of essential-singularity type. At the critical point, fermion mass operator ;j;'lj; has a large anomalous dimension 'Yti;.p = 1, -
The Real Problem with Perturbative Quantum Field Theory
The Real Problem with Perturbative Quantum Field Theory James Duncan Fraser Abstract The perturbative approach to quantum field theory (QFT) has long been viewed with suspicion by philosophers of science. This paper offers a diag- nosis of its conceptual problems. Drawing on Norton's ([2012]) discussion of the notion of approximation I argue that perturbative QFT ought to be understood as producing approximations without specifying an underlying QFT model. This analysis leads to a reassessment of common worries about perturbative QFT. What ends up being the key issue with the approach on this picture is not mathematical rigour, or the threat of inconsistency, but the need for a physical explanation of its empirical success. 1 Three Worries about Perturbative Quantum Field Theory 2 The Perturbative Formalism 2.1 Expanding the S-matrix 2.2 Perturbative renormalization 3 Approximations and Models 4 Perturbative Quantum Field Theory Produces Approximations 5 The Real Problem 1 Three Worries about Perturbative Quantum Field Theory On the face of it, the perturbative approach to quantum field theory (QFT) ought to be of great interest to philosophers of physics.1 Perturbation theory has long 1I use the terms `perturbative approach to QFT' and `perturbative QFT' here to refer to the perturbative treatment of interacting field theories that is invariable found in QFT textbooks and forms the basis of much work in high energy physics. I am not assuming that this `approach' 1 played a special role in the QFT programme. The axiomatic and effective field theory approaches to QFT, which have been the locus of much philosophical at- tention in recent years, have their roots in the perturbative formalism pioneered by Feynman, Schwinger and Tomonaga in the 1940s. -
GSS: Gauge and String Theories
GSS: Gauge and String Theories S. Bellucci (Resp.), S. Ferrara (Ass.), S. Krivonos (Osp.), A. Sutulin (Bors. PD), B.N. Tiwari (Ospite), A. Yeranyan (Bors. Fermi Institute) Research Activity S. Ferrara investigated different aspects of black-hole physics, which include a classification of charge- orbits for extremal single-center black holes and first-order flows of extremal black holes with different BPS properties. He also investigated some aspects of multi-center black holes and, in particular, the classification of two-center orbits and first order flows for multi-center composites. He studied several aspects of supersymmetry breaking. Applications to Particle Physics or to inflation rest on N=1 spontaneously broken supergravity where some multiplets mediate supersymmetry breaking while others accommodate the inflaton. The supersymmetric extension of the Starobinsky model depends on the off-shell formulation of the local supersymmetry algebra. This allows one to show the equivalence of this higher curvature theory to a standard Einstein supergravity. Depending on the chosen formulation the model corresponds to supergravity coupled either to two massive chiral multiplets, one of which is the goldstino multiplet, or to a massive vector multiplet. He also introduced a set of minimal models, where the inflaton sector is described by a single scalar field (with D term and Fayet-Iliopoulos term generating potential), unlike in models based on chiral multiplets based on an F-term potential. In minimal models the scalaron is dual to the inflaton, and being the member of a massive vector multiplet, it is the superpartner of the Stueckelberg field. Subsequently, replacing the Goldstino multiplet with its non-linear realization via a nilpotent superfield, he arrived at a new universal Volkov-Akulov-Starobinsky Supergravity. -
A Complete Spectroscopic Survey of the Milky Way Satellite Segue 1: the Darkest Galaxy
Haverford College Haverford Scholarship Faculty Publications Astronomy 2011 A Complete Spectroscopic Survey of the Milky Way Satellite Segue 1: The Darkest Galaxy Joshua D. Simon Marla Geha Quinn E. Minor Beth Willman Haverford College Follow this and additional works at: https://scholarship.haverford.edu/astronomy_facpubs Repository Citation A Complete Spectroscopic Survey of the Milky Way satellite Segue 1: Dark matter content, stellar membership and binary properties from a Bayesian analysis - Martinez, Gregory D. et al. Astrophys.J. 738 (2011) 55 arXiv:1008.4585 [astro-ph.GA] This Journal Article is brought to you for free and open access by the Astronomy at Haverford Scholarship. It has been accepted for inclusion in Faculty Publications by an authorized administrator of Haverford Scholarship. For more information, please contact [email protected]. The Astrophysical Journal, 733:46 (20pp), 2011 May 20 doi:10.1088/0004-637X/733/1/46 C 2011. The American Astronomical Society. All rights reserved. Printed in the U.S.A. A COMPLETE SPECTROSCOPIC SURVEY OF THE MILKY WAY SATELLITE SEGUE 1: THE DARKEST GALAXY∗ Joshua D. Simon1, Marla Geha2, Quinn E. Minor3, Gregory D. Martinez3, Evan N. Kirby4,8, James S. Bullock3, Manoj Kaplinghat3, Louis E. Strigari5,8, Beth Willman6, Philip I. Choi7, Erik J. Tollerud3, and Joe Wolf3 1 Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101, USA; [email protected] 2 Astronomy Department, Yale University, New Haven, CT 06520, USA; [email protected] -
Is There Tension Between Observed Small Scale Structure and Cold Dark Matter?
Is there tension between observed small scale structure and cold dark matter? Louis Strigari Stanford University Cosmic Frontier 2013 March 8, 2013 Predictions of the standard Cold Dark Matter model 26 3 1 1. Density profiles rise towards the centersσannv 3of 10galaxies− cm s− (1) h i' ⇥ ⇢ Universal for all halo masses ⇢(r)= s (2) (r/r )(1 + r/r )2 Navarro-Frenk-White (NFW) model s s 2. Abundance of ‘sub-structure’ (sub-halos) in galaxies Sub-halos comprise few percent of total halo mass Most of mass contained in highest- mass sub-halos Subhalo Mass Function Mass[Solar mass] 1 Problems with the standard Cold Dark Matter model 1. Density of dark matter halos: Faint, dark matter-dominated galaxies appear less dense that predicted in simulations General arguments: Kleyna et al. MNRAS 2003, 2004;Goerdt et al. APJ2006; de Blok et al. AJ 2008 Dwarf spheroidals: Gilmore et al. APJ 2007; Walker & Penarrubia et al. APJ 2011; Angello & Evans APJ 2012 2. ‘Missing satellites problem’: Simulations have more dark matter subhalos than there are observed dwarf satellite galaxies Earilest papers: Kauffmann et al. 1993; Klypin et al. 1999; Moore et al. 1999 Solutions to the issues in Cold Dark Matter 1. The theory is wrong i) Not enough physics in theory/simulations (Talks yesterday by M. Boylan-Kolchin, M. Kuhlen) [Wadepuhl & Springel MNRAS 2011; Parry et al. MRNAS 2011; Pontzen & Governato MRNAS 2012; Brooks et al. ApJ 2012] ii) Cosmology/dark matter is wrong (Talk yesterday by A. Peter) 2. The data is wrong i) Kinematics of dwarf spheroidals (dSphs) are more difficult than assumed ii) Counting satellites a) Many more faint satellites around the Milky Way b) Milky Way is an oddball [Liu et al. -
Global Program
PROGRAM Monday morning, July 13th La Sapienza Roma - Aula Magna 09:00 - 10:00 Inaugural Session Chairperson: Paolo de Bernardis Welcoming addresses Remo Ruffini (ICRANet), Yvonne Choquet-Bruhat (French Académie des Sciences), Jose’ Funes (Vatican City), Ricardo Neiva Tavares (Ambassador of Brazil), Sargis Ghazaryan (Ambassador of Armenia), Francis Everitt (Stanford University) and Chris Fryer (University of Arizona) Marcel Grossmann Awards Yakov Sinai, Martin Rees, Sachiko Tsuruta, Ken’Ichi Nomoto, ESA (acceptance speech by Johann-Dietrich Woerner, ESA Director General) Lectiones Magistrales Yakov Sinai (Princeton University) 10:00 - 10:35 Deterministic chaos Martin Rees (University of Cambridge) 10:35 - 11:10 How our understanding of cosmology and black holes has been revolutionised since the 1960s 11:10 - 11:35 Group Picture - Coffee Break Gerard 't Hooft (University of Utrecht) 11:35 - 12:10 Local Conformal Symmetry in Black Holes, Standard Model, and Quantum Gravity Plenary Session: Mathematics and GR Katarzyna Rejzner (University of York) 12:10 - 12:40 Effective quantum gravity observables and locally covariant QFT Zvi Bern (UCLA Physics & Astronomy) 12:40 - 13:10 Ultraviolet surprises in quantum gravity 14:30 - 18:00 Parallel Session 18:45 - 20:00 Stephen Hawking (teleconference) (University of Cambridge) Public Lecture Fire in the Equations Monday afternoon, July 13th Code Classroom Title Chairperson AC2 ChN1 MHD processes near compact objects Sergej Moiseenko FF Extended Theories of Gravity and Quantum Salvatore Capozziello, Gabriele AT1 A Cabibbo Cosmology Gionti AT3 A FF3 Wormholes, Energy Conditions and Time Machines Francisco Lobo Localized selfgravitating field systems in the AT4 FF6 Dmitry Galtsov, Michael Volkov Einstein and alternatives theories of gravity BH1:Binary Black Holes as Sources of Pablo Laguna, Anatoly M. -
Ads₄/CFT₃ and Quantum Gravity
AdS/CFT and quantum gravity Ioannis Lavdas To cite this version: Ioannis Lavdas. AdS/CFT and quantum gravity. Mathematical Physics [math-ph]. Université Paris sciences et lettres, 2019. English. NNT : 2019PSLEE041. tel-02966558 HAL Id: tel-02966558 https://tel.archives-ouvertes.fr/tel-02966558 Submitted on 14 Oct 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Prepar´ ee´ a` l’Ecole´ Normale Superieure´ AdS4/CF T3 and Quantum Gravity Soutenue par Composition du jury : Ioannis Lavdas Costas BACHAS Le 03 octobre 2019 Ecole´ Normale Superieure Directeur de These Guillaume BOSSARD Ecole´ Polytechnique Membre du Jury o Ecole´ doctorale n 564 Elias KIRITSIS Universite´ Paris-Diderot et Universite´ de Rapporteur Physique en ˆIle-de-France Crete´ Michela PETRINI Sorbonne Universite´ President´ du Jury Nicholas WARNER University of Southern California Membre du Jury Specialit´ e´ Alberto ZAFFARONI Physique Theorique´ Universita´ Milano-Bicocca Rapporteur Contents Introduction 1 I 3d N = 4 Superconformal Theories and type IIB Supergravity Duals6 1 3d N = 4 Superconformal Theories7 1.1 N = 4 supersymmetric gauge theories in three dimensions..............7 1.2 Linear quivers and their Brane Realizations...................... 10 1.3 Moduli Space and Symmetries............................ -
Arxiv:1102.4624V1 [Hep-Th] 22 Feb 2011 (Sec
Renormalisation group and the Planck scale Daniel F. Litim∗ Department of Physics and Astronomy, University of Sussex, Brighton, BN1 9QH, U.K. I discuss the renormalisation group approach to gravity, its link to S. Weinberg's asymptotic safety scenario, and give an overview of results with applications to particle physics and cosmology. I. INTRODUCTION Einstein's theory of general relativity is the remarkably successful classical theory of the gravitational force, charac- −11 3 2 terised by Newton's coupling constant GN = 6:67×10 m =(kg s ) and a small cosmological constant Λ. Experimen- tally, its validity has been confirmed over many orders of magnitude in length scales ranging from the sub-millimeter regime up to solar system size. At larger length scales, the standard model of cosmology including dark matter and dark energy components fits the data well. At shorter length scales, quantum effects are expected to become impor- tant. An order of magnitude estimate for the quantum scale of gravity { the Planck scale { is obtained by dimensional p 3 −33 analysis leading to the Planck length `Pl ≈ ~GN =c of the order of 10 cm, with c the speed of light. In particle physics units this translates into the Planck mass 19 MPl ≈ 10 GeV : (1) While this energy scale is presently out of reach for earth-based particle accelerator experiments, fingerprints of Planck-scale physics can nevertheless become accessible through cosmological data from the very early universe. From a theory perspective, it is widely expected that a fundamental understanding of Planck scale physics requires a quantum theory of gravity. -
Singlet Glueballs in Klebanov-Strassler Theory
Singlet Glueballs In Klebanov-Strassler Theory A DISSERTATION SUBMITTED TO THE FACULTY OF THE GRADUATE SCHOOL OF THE UNIVERSITY OF MINNESOTA BY IVAN GORDELI IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF Doctor of Philosophy ARKADY VAINSHTEIN April, 2016 c IVAN GORDELI 2016 ALL RIGHTS RESERVED Acknowledgements First of all I would like to thank my scientific adviser - Arkady Vainshtein for his incredible patience and support throughout the course of my Ph.D. program. I would also like to thank my committee members for taking time to read and review my thesis, namely Ronald Poling, Mikhail Shifman and Alexander Voronov. I am deeply grateful to Vasily Pestun for his support and motivation. Same applies to my collaborators Dmitry Melnikov and Anatoly Dymarsky who have suggested this research topic to me. I am thankful to my other collaborator - Peter Koroteev. I would like to thank Emil Akhmedov, A.Yu. Morozov, Andrey Mironov, M.A. Olshanetsky, Antti Niemi, K.A. Ter-Martirosyan, M.B. Voloshin, Andrey Levin, Andrei Losev, Alexander Gorsky, S.M. Kozel, S.S. Gershtein, M. Vysotsky, Alexander Grosberg, Tony Gherghetta, R.B. Nevzorov, D.I. Kazakov, M.V. Danilov, A. Chervov and all other great teachers who have shaped everything I know about Theoretical Physics. I am deeply grateful to all my friends and colleagues who have contributed to discus- sions and supported me throughout those years including A. Arbuzov, L. Kushnir, K. Kozlova, A. Shestov, V. Averina, A. Talkachova, A. Talkachou, A. Abyzov, V. Poberezh- niy, A. Alexandrov, G. Nozadze, S. Solovyov, A. Zotov, Y. Chernyakov, N. -
Black Holes and Qubits
Subnuclear Physics: Past, Present and Future Pontifical Academy of Sciences, Scripta Varia 119, Vatican City 2014 www.pas.va/content/dam/accademia/pdf/sv119/sv119-duff.pdf Black Holes and Qubits MICHAEL J. D UFF Blackett Labo ratory, Imperial C ollege London Abstract Quantum entanglement lies at the heart of quantum information theory, with applications to quantum computing, teleportation, cryptography and communication. In the apparently separate world of quantum gravity, the Hawking effect of radiating black holes has also occupied centre stage. Despite their apparent differences, it turns out that there is a correspondence between the two. Introduction Whenever two very different areas of theoretical physics are found to share the same mathematics, it frequently leads to new insights on both sides. Here we describe how knowledge of string theory and M-theory leads to new discoveries about Quantum Information Theory (QIT) and vice-versa (Duff 2007; Kallosh and Linde 2006; Levay 2006). Bekenstein-Hawking entropy Every object, such as a star, has a critical size determined by its mass, which is called the Schwarzschild radius. A black hole is any object smaller than this. Once something falls inside the Schwarzschild radius, it can never escape. This boundary in spacetime is called the event horizon. So the classical picture of a black hole is that of a compact object whose gravitational field is so strong that nothing, not even light, can escape. Yet in 1974 Stephen Hawking showed that quantum black holes are not entirely black but may radiate energy, due to quantum mechanical effects in curved spacetime. In that case, they must possess the thermodynamic quantity called entropy.