Braids, 3-Manifolds, Elementary Particles: Number Theory and Symmetry in Particle Physics
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Quantum Simplicial Geometry in the Group Field Theory Formalism
Quantum simplicial geometry in the group field theory formalism: reconsidering the Barrett-Crane model Aristide Baratin∗1 and Daniele Oriti†2 1Centre de Physique Th´eorique, CNRS UMR 7644, Ecole Polytechnique F-9112 Palaiseau Cedex, France 2Max-Planck-Institut f¨ur Gravitationsphysik Albert Einstein Institute Am M¨uhlenberg 2, 14476, Golm, Germany, EU A dual formulation of group field theories, obtained by a Fourier transform mapping functions on a group to functions on its Lie algebra, has been proposed recently. In the case of the Ooguri model for SO(4) BF theory, the variables of the dual field variables are thus so(4) bivectors, which have a direct interpretation as the discrete B variables. Here we study a modification of the model by means of a constraint operator implementing the simplicity of the bivectors, in such a way that projected fields describe metric tetrahedra. This involves a extension of the usual GFT framework, where boundary operators are labelled by projected spin network states. By construction, the Feynman amplitudes are simplicial path integrals for constrained BF theory. We show that the spin foam formulation of these amplitudes corresponds to a variant of the Barrett-Crane model for quantum gravity. We then re-examin the arguments against the Barrett-Crane model(s), in light of our construction. Introduction Group field theories (GFT) represent a second quantized framework for both spin networks and simplicial geometry [6, 7, 9], field theories on group manifolds (or Lie algebras) producing Feynman amplitudes which can be equivalently expressed as simplicial gravity path integrals [5] or spin foam models [10], in turn covariant formulations of spin networks dynamics [1]3. -
Dimensional Topological Quantum Field Theory from a Tight-Binding Model of Interacting Spinless Fermions
This is a repository copy of (3+1)-dimensional topological quantum field theory from a tight-binding model of interacting spinless fermions. White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/99993/ Version: Accepted Version Article: Cirio, M, Palumbo, G and Pachos, JK (2014) (3+1)-dimensional topological quantum field theory from a tight-binding model of interacting spinless fermions. Physical Review B, 90 (8). 085114. ISSN 2469-9950 https://doi.org/10.1103/PhysRevB.90.085114 Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version - refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher’s website. Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing [email protected] including the URL of the record and the reason for the withdrawal request. [email protected] https://eprints.whiterose.ac.uk/ (3+1)-dimensional topological quantum field theory from a tight-binding model of interacting spinless fermions Mauro Cirio,1 Giandomenico Palumbo,2 and Jiannis K. Pachos2 1Centre for Engineered Quantum Systems, Department of Physics and Astronomy, Macquarie University, North Ryde, NSW 2109, Australia 2School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom (Dated: July 15, 2014) Currently, there is much interest in discovering analytically tractable (3 + 1)-dimensional models that describe interacting fermions with emerging topological properties. -
Construction and Examples of Higher Gauge Theories∗
Construction and examples of higher gauge theories∗ Tijana Radenkovi´cy Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia Marko Vojinovi´cz Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia Abstract We provide several examples of higher gauge theories, constructed as gener- alizations of a BF model to 2BF and 3BF models with constraints. Using the framework of higher category theory, we introduce appropriate 2-groups and 3- groups, and construct the actions for the corresponding constrained 2BF and 3BF theories. In this way, we can construct actions which describe the correct dynamics of Yang-Mills, Klein-Gordon, Dirac, Weyl, and Majorana fields coupled to Einstein-Cartan gravity. Each action is naturally split into a topological sector and a sector with simplicity constraints. The properties of the higher gauge group structure opens up a possibility of a nontrivial unification of all fields. 1. Introduction The quantization of the gravitational field is one of the fundamental open problems in modern physics. There are various approaches to this prob- lem, some of which have developed into vast research frameworks. One of such frameworks is the Loop Quantum Gravity approach, which aims to establish a nonperturbative quantization of gravity, both canonically and covariantly [1, 2, 3]. The covariant approach is slightly more general, and ∗ This work was supported by the project ON171031 of the Ministry of Education, Sci- ence and Technological Development (MPNTR) of the Republic of Serbia, and partially by the bilateral scientific cooperation between Austria and Serbia through the project \Causality in Quantum Mechanics and Quantum Gravity - 2018-2019", no. -
On Some Generation Methods of Finite Simple Groups
Introduction Preliminaries Special Kind of Generation of Finite Simple Groups The Bibliography On Some Generation Methods of Finite Simple Groups Ayoub B. M. Basheer Department of Mathematical Sciences, North-West University (Mafikeng), P Bag X2046, Mmabatho 2735, South Africa Groups St Andrews 2017 in Birmingham, School of Mathematics, University of Birmingham, United Kingdom 11th of August 2017 Ayoub Basheer, North-West University, South Africa Groups St Andrews 2017 Talk in Birmingham Introduction Preliminaries Special Kind of Generation of Finite Simple Groups The Bibliography Abstract In this talk we consider some methods of generating finite simple groups with the focus on ranks of classes, (p; q; r)-generation and spread (exact) of finite simple groups. We show some examples of results that were established by the author and his supervisor, Professor J. Moori on generations of some finite simple groups. Ayoub Basheer, North-West University, South Africa Groups St Andrews 2017 Talk in Birmingham Introduction Preliminaries Special Kind of Generation of Finite Simple Groups The Bibliography Introduction Generation of finite groups by suitable subsets is of great interest and has many applications to groups and their representations. For example, Di Martino and et al. [39] established a useful connection between generation of groups by conjugate elements and the existence of elements representable by almost cyclic matrices. Their motivation was to study irreducible projective representations of the sporadic simple groups. In view of applications, it is often important to exhibit generating pairs of some special kind, such as generators carrying a geometric meaning, generators of some prescribed order, generators that offer an economical presentation of the group. -
Janko's Sporadic Simple Groups
Janko’s Sporadic Simple Groups: a bit of history Algebra, Geometry and Computation CARMA, Workshop on Mathematics and Computation Terry Gagen and Don Taylor The University of Sydney 20 June 2015 Fifty years ago: the discovery In January 1965, a surprising announcement was communicated to the international mathematical community. Zvonimir Janko, working as a Research Fellow at the Institute of Advanced Study within the Australian National University had constructed a new sporadic simple group. Before 1965 only five sporadic simple groups were known. They had been discovered almost exactly one hundred years prior (1861 and 1873) by Émile Mathieu but the proof of their simplicity was only obtained in 1900 by G. A. Miller. Finite simple groups: earliest examples É The cyclic groups Zp of prime order and the alternating groups Alt(n) of even permutations of n 5 items were the earliest simple groups to be studied (Gauss,≥ Euler, Abel, etc.) É Evariste Galois knew about PSL(2,p) and wrote about them in his letter to Chevalier in 1832 on the night before the duel. É Camille Jordan (Traité des substitutions et des équations algébriques,1870) wrote about linear groups defined over finite fields of prime order and determined their composition factors. The ‘groupes abéliens’ of Jordan are now called symplectic groups and his ‘groupes hypoabéliens’ are orthogonal groups in characteristic 2. É Émile Mathieu introduced the five groups M11, M12, M22, M23 and M24 in 1861 and 1873. The classical groups, G2 and E6 É In his PhD thesis Leonard Eugene Dickson extended Jordan’s work to linear groups over all finite fields and included the unitary groups. -
Aspects of Loop Quantum Gravity
Aspects of loop quantum gravity Alexander Nagen 23 September 2020 Submitted in partial fulfilment of the requirements for the degree of Master of Science of Imperial College London 1 Contents 1 Introduction 4 2 Classical theory 12 2.1 The ADM / initial-value formulation of GR . 12 2.2 Hamiltonian GR . 14 2.3 Ashtekar variables . 18 2.4 Reality conditions . 22 3 Quantisation 23 3.1 Holonomies . 23 3.2 The connection representation . 25 3.3 The loop representation . 25 3.4 Constraints and Hilbert spaces in canonical quantisation . 27 3.4.1 The kinematical Hilbert space . 27 3.4.2 Imposing the Gauss constraint . 29 3.4.3 Imposing the diffeomorphism constraint . 29 3.4.4 Imposing the Hamiltonian constraint . 31 3.4.5 The master constraint . 32 4 Aspects of canonical loop quantum gravity 35 4.1 Properties of spin networks . 35 4.2 The area operator . 36 4.3 The volume operator . 43 2 4.4 Geometry in loop quantum gravity . 46 5 Spin foams 48 5.1 The nature and origin of spin foams . 48 5.2 Spin foam models . 49 5.3 The BF model . 50 5.4 The Barrett-Crane model . 53 5.5 The EPRL model . 57 5.6 The spin foam - GFT correspondence . 59 6 Applications to black holes 61 6.1 Black hole entropy . 61 6.2 Hawking radiation . 65 7 Current topics 69 7.1 Fractal horizons . 69 7.2 Quantum-corrected black hole . 70 7.3 A model for Hawking radiation . 73 7.4 Effective spin-foam models . -
Sporadic Sics and Exceptional Lie Algebras
Sporadic SICs and Exceptional Lie Algebras Blake C. Staceyy yQBism Group, Physics Department, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston MA 02125, USA November 13, 2019 Abstract Sometimes, mathematical oddities crowd in upon one another, and the exceptions to one classification scheme reveal themselves as fellow-travelers with the exceptions to a quite different taxonomy. 1 Preliminaries A set of equiangular lines is a set of unit vectors in a d-dimensional vector space such that the magnitude of the inner product of any pair is constant: 1; j = k; jhv ; v ij = (1) j k α; j 6= k: The maximum number of equiangular lines in a space of dimension d (the so-called Gerzon bound) is d(d+1)=2 for real vector spaces and d2 for complex. In the real case, the Gerzon bound is only known to be attained in dimensions 2, 3, 7 and 23, and we know it can't be attained in general. If you like peculiar alignments of mathematical topics, the appearance of 7 and 23 might make your ears prick up here. If you made the wild guess that the octonions and the Leech lattice are just around the corner. you'd be absolutely right. Meanwhile, the complex case is of interest for quantum information theory, because a set of d2 equiangular lines in Cd specifies a measurement that can be performed upon a quantum-mechanical system. These measurements are highly symmetric, in that the lines which specify them are equiangular, and they are \informationally complete" in a sense that quantum theory makes precise. -
Loop and Spin Foam Quantum Gravity: a Brief Guide for Beginners
AEI-2006-004 hep-th/0601129 January 18th, 2006 Loop and Spin Foam Quantum Gravity: A Brief Guide for Beginners Hermann Nicolai and Kasper Peeters Max-Planck-Institut f¨ur Gravitationsphysik Albert-Einstein-Institut Am M¨uhlenberg 1 14476 Golm, GERMANY hermann.nicolai, [email protected] Abstract: We review aspects of loop quantum gravity and spin foam models at an introductory level, with special attention to questions frequently asked by non-specialists. arXiv:hep-th/0601129 v2 16 Feb 2006 Contributed article to “An assessment of current paradigms in the physics of fundamental interactions”, ed. I. Stamatescu, Springer Verlag. 1. Quantum Einstein gravity ics approach [7], addresses several aspects of the problem that are currently outside the main focus The assumption that Einstein’s classical theory of of string theory, in particular the question of back- gravity can be quantised non-perturbatively is at the ground independence and the quantisation of geom- root of a wide variety of approaches to quantum etry. Whereas there is a rather direct link between gravity. The assumption constitutes the basis of sev- (perturbative) string theory and classical space-time eral discrete methods [1], such as dynamical tri- concepts, and string theory can therefore rely on fa- angulations and Regge calculus, but it also implic- miliar notions and concepts, such as the notion of a itly underlies the older Euclidean path integral ap- particle and the S-matrix, the task is harder for LQG, proach [2, 3] and the somewhat more indirect ar- as it must face up right away to the question of what guments which suggest that there may exist a non- an observable quantity is in the absence of a proper trivial fixed point of the renormalisation group [4–6]. -
A Natural Representation of the Fischer-Griess Monster
Proc. Nati. Acad. Sci. USA Vol. 81, pp. 3256-3260, May 1984 Mathematics A natural representation of the Fischer-Griess Monster with the modular function J as character (vertex operators/finite simple group Fl/Monstrous Moonshine/affine Lie algebras/basic modules) I. B. FRENKEL*t, J. LEPOWSKY*t, AND A. MEURMANt *Department of Mathematics, Rutgers University, New Brunswick, NJ 08903; and tMathematical Sciences Research Institute, Berkeley, CA 94720 Communicated by G. D. Mostow, February 3, 1984 ABSTRACT We announce the construction of an irreduc- strange discoveries could make sense. However, instead of ible graded module V for an "affine" commutative nonassocia- illuminating the mysteries, he added a new one, by con- tive algebra S. This algebra is an "affinization" of a slight structing a peculiar commutative nonassociative algebra B variant R of the conMnutative nonassociative algebra B de- and proving directly that its automorphism group contains fined by Griess in his construction of the Monster sporadic F1. group F1. The character of V is given by the modular function The present work started as an attempt to explain the ap- J(q) _ q' + 0 + 196884q + .... We obtain a natural action of pearance of J(q) as well as the structure of B. Our under- the Monster on V compatible with the action of R, thus con- standing of these phenomena has now led us to conceptual ceptually explaining a major part of the numerical observa- constructions of several objects: V; a variant a of B; an "af- tions known as Monstrous Moonshine. Our construction starts finization" 9a of@a; and F1, which appears as a group of oper- from ideas in the theory of the basic representations of affine ators on V and at the sajne time as a group of algebra auto- Lie algebras and develops further the cadculus of vertex opera- morphisms of R and of 9a. -
Arxiv:1108.1178V2 [Gr-Qc]
Quantum simplicial geometry in the group field theory formalism: reconsidering the Barrett-Crane model Aristide Baratin∗1 and Daniele Oriti†2 1Centre de Physique Th´eorique, CNRS UMR 7644, Ecole Polytechnique F-9112 Palaiseau Cedex, France 2Max-Planck-Institut f¨ur Gravitationsphysik Albert Einstein Institute Am M¨uhlenberg 2, 14476, Golm, Germany, EU A dual formulation of group field theories, obtained by a Fourier transform mapping functions on a group to functions on its Lie algebra, has been proposed recently. In the case of the Ooguri model for SO(4) BF theory, the variables of the dual field variables are thus so(4) bivectors, which have a direct interpretation as the discrete B variables. Here we study a modification of the model by means of a constraint operator implementing the simplicity of the bivectors, in such a way that projected fields describe metric tetrahedra. This involves a extension of the usual GFT framework, where boundary operators are labelled by projected spin network states. By construction, the Feynman amplitudes are simplicial path integrals for constrained BF theory. We show that the spin foam formulation of these amplitudes corresponds to a variant of the Barrett-Crane model for quantum gravity. We then re-examin the arguments against the Barrett-Crane model(s), in light of our construction. Introduction Group field theories (GFT) represent a second quantized framework for both spin networks and simplicial geometry [6, 7, 9], field theories on group manifolds (or Lie algebras) producing Feynman amplitudes which can be equivalently expressed as simplicial gravity path integrals [5] or spin foam models [10], in turn covariant formulations of spin networks dynamics [1]3. -
Arxiv:1305.5974V1 [Math-Ph]
INTRODUCTION TO SPORADIC GROUPS for physicists Luis J. Boya∗ Departamento de F´ısica Te´orica Universidad de Zaragoza E-50009 Zaragoza, SPAIN MSC: 20D08, 20D05, 11F22 PACS numbers: 02.20.a, 02.20.Bb, 11.24.Yb Key words: Finite simple groups, sporadic groups, the Monster group. Juan SANCHO GUIMERA´ In Memoriam Abstract We describe the collection of finite simple groups, with a view on physical applications. We recall first the prime cyclic groups Zp, and the alternating groups Altn>4. After a quick revision of finite fields Fq, q = pf , with p prime, we consider the 16 families of finite simple groups of Lie type. There are also 26 extra “sporadic” groups, which gather in three interconnected “generations” (with 5+7+8 groups) plus the Pariah groups (6). We point out a couple of physical applications, in- cluding constructing the biggest sporadic group, the “Monster” group, with close to 1054 elements from arguments of physics, and also the relation of some Mathieu groups with compactification in string and M-theory. ∗[email protected] arXiv:1305.5974v1 [math-ph] 25 May 2013 1 Contents 1 Introduction 3 1.1 Generaldescriptionofthework . 3 1.2 Initialmathematics............................ 7 2 Generalities about groups 14 2.1 Elementarynotions............................ 14 2.2 Theframeworkorbox .......................... 16 2.3 Subgroups................................. 18 2.4 Morphisms ................................ 22 2.5 Extensions................................. 23 2.6 Familiesoffinitegroups ......................... 24 2.7 Abeliangroups .............................. 27 2.8 Symmetricgroup ............................. 28 3 More advanced group theory 30 3.1 Groupsoperationginspaces. 30 3.2 Representations.............................. 32 3.3 Characters.Fourierseries . 35 3.4 Homological algebra and extension theory . 37 3.5 Groupsuptoorder16.......................... -
Finite Groups Whose Element Orders Are Consecutive Integers
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector JOURNAL OF ALGEBRA 143, 388X)0 (1991) Finite Groups Whose Element Orders Are Consecutive Integers ROLF BRANDL Mathematisches Institui, Am Hubland 12, D-W-8700 Wiirzberg, Germany AND SHI WUJIE Mathematics Department, Southwest-China Teachers University, Chongqing, China Communicated by G. Glauberman Received February 28, 1986 DEDICATED TO PROFESSORB. H. NEUMANN ON HIS 80~~ BIRTHDAY There are various characterizations of groups by conditions on the orders of its elements. For example, in [ 8, 1] the finite groups all of whose elements have prime power order have been classified. In [2, 16-181 some simple groups have been characterized by conditions on the orders of its elements and B. H. Neumann [12] has determined all groups whose elements have orders 1, 2, and 3. The latter groups are OC3 groups in the sense of the following. DEFINITION. Let n be a positive integer. Then a group G is an OC, group if every element of G has order <n and for each m <n there exists an element of G having order m. In this paper we give a complete classification of finite OC, groups. The notation is standard; see [S, 111. In addition, for a prime q, a Sylow q-sub- group of the group G is denoted by P,. Moreover Z{ stands for the direct product of j copies of Zj and G = [N] Q denotes the split extension of a normal subgroup N of G by a complement Q.