Are Octonions Necessary to the Standard Model?
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Math 651 Homework 1 - Algebras and Groups Due 2/22/2013
Math 651 Homework 1 - Algebras and Groups Due 2/22/2013 1) Consider the Lie Group SU(2), the group of 2 × 2 complex matrices A T with A A = I and det(A) = 1. The underlying set is z −w jzj2 + jwj2 = 1 (1) w z with the standard S3 topology. The usual basis for su(2) is 0 i 0 −1 i 0 X = Y = Z = (2) i 0 1 0 0 −i (which are each i times the Pauli matrices: X = iσx, etc.). a) Show this is the algebra of purely imaginary quaternions, under the commutator bracket. b) Extend X to a left-invariant field and Y to a right-invariant field, and show by computation that the Lie bracket between them is zero. c) Extending X, Y , Z to global left-invariant vector fields, give SU(2) the metric g(X; X) = g(Y; Y ) = g(Z; Z) = 1 and all other inner products zero. Show this is a bi-invariant metric. d) Pick > 0 and set g(X; X) = 2, leaving g(Y; Y ) = g(Z; Z) = 1. Show this is left-invariant but not bi-invariant. p 2) The realification of an n × n complex matrix A + −1B is its assignment it to the 2n × 2n matrix A −B (3) BA Any n × n quaternionic matrix can be written A + Bk where A and B are complex matrices. Its complexification is the 2n × 2n complex matrix A −B (4) B A a) Show that the realification of complex matrices and complexifica- tion of quaternionic matrices are algebra homomorphisms. -
CLIFFORD ALGEBRAS and THEIR REPRESENTATIONS Introduction
CLIFFORD ALGEBRAS AND THEIR REPRESENTATIONS Andrzej Trautman, Uniwersytet Warszawski, Warszawa, Poland Article accepted for publication in the Encyclopedia of Mathematical Physics c 2005 Elsevier Science Ltd ! Introduction Introductory and historical remarks Clifford (1878) introduced his ‘geometric algebras’ as a generalization of Grassmann alge- bras, complex numbers and quaternions. Lipschitz (1886) was the first to define groups constructed from ‘Clifford numbers’ and use them to represent rotations in a Euclidean ´ space. E. Cartan discovered representations of the Lie algebras son(C) and son(R), n > 2, that do not lift to representations of the orthogonal groups. In physics, Clifford algebras and spinors appear for the first time in Pauli’s nonrelativistic theory of the ‘magnetic elec- tron’. Dirac (1928), in his work on the relativistic wave equation of the electron, introduced matrices that provide a representation of the Clifford algebra of Minkowski space. Brauer and Weyl (1935) connected the Clifford and Dirac ideas with Cartan’s spinorial represen- tations of Lie algebras; they found, in any number of dimensions, the spinorial, projective representations of the orthogonal groups. Clifford algebras and spinors are implicit in Euclid’s solution of the Pythagorean equation x2 y2 + z2 = 0 which is equivalent to − y x z p = 2 p q (1) −z y + x q ! " ! " # $ so that x = q2 p2, y = p2 + q2, z = 2pq. If the numbers appearing in (1) are real, then − this equation can be interpreted as providing a representation of a vector (x, y, z) R3, null ∈ with respect to a quadratic form of signature (1, 2), as the ‘square’ of a spinor (p, q) R2. -
Generically Split Octonion Algebras and A1-Homotopy Theory
Generically split octonion algebras and A1-homotopy theory Aravind Asok∗ Marc Hoyoisy Matthias Wendtz Abstract 1 We study generically split octonion algebras over schemes using techniques of A -homotopy theory. By combining affine representability results with techniques of obstruction theory, we establish classifica- tion results over smooth affine schemes of small dimension. In particular, for smooth affine schemes over algebraically closed fields, we show that generically split octonion algebras may be classified by charac- teristic classes including the second Chern class and another “mod 3” invariant. We review Zorn’s “vector matrix” construction of octonion algebras, generalized to rings by various authors, and show that generi- cally split octonion algebras are always obtained from this construction over smooth affine schemes of low dimension. Finally, generalizing P. Gille’s analysis of octonion algebras with trivial norm form, we observe that generically split octonion algebras with trivial associated spinor bundle are automatically split in low dimensions. Contents 1 Introduction 1 2 Octonion algebras, algebra and geometry 6 2.1 Octonion algebras and Zorn’s vector matrices......................................7 2.2 Octonion algebras and G2-torsors............................................9 2.3 Homogeneous spaces related to G2 and octonions.................................... 11 1 3 A -homotopy sheaves of BNis G2 17 1 3.1 Some A -fiber sequences................................................. 17 1 3.2 Characteristic maps and strictly A -invariant sheaves.................................. 19 3.3 Realization and characteristic maps........................................... 21 1 3.4 Some low degree A -homotopy sheaves of BNis Spinn and BNis G2 .......................... 24 4 Classifying octonion algebras 29 4.1 Classifying generically split octonion algebras...................................... 30 4.2 When are octonion algebras isomorphic to Zorn algebras?............................... -
On the Complexification of the Classical Geometries And
On the complexication of the classical geometries and exceptional numb ers April Intro duction The classical groups On R Spn R and GLn C app ear as the isometry groups of sp ecial geome tries on a real vector space In fact the orthogonal group On R represents the linear isomorphisms of arealvector space V of dimension nleaving invariant a p ositive denite and symmetric bilinear form g on V The symplectic group Spn R represents the isometry group of a real vector space of dimension n leaving invariant a nondegenerate skewsymmetric bilinear form on V Finally GLn C represents the linear isomorphisms of a real vector space V of dimension nleaving invariant a complex structure on V ie an endomorphism J V V satisfying J These three geometries On R Spn R and GLn C in GLn Rintersect even pairwise in the unitary group Un C Considering now the relativeversions of these geometries on a real manifold of dimension n leads to the notions of a Riemannian manifold an almostsymplectic manifold and an almostcomplex manifold A symplectic manifold however is an almostsymplectic manifold X ie X is a manifold and is a nondegenerate form on X so that the form is closed Similarly an almostcomplex manifold X J is called complex if the torsion tensor N J vanishes These three geometries intersect in the notion of a Kahler manifold In view of the imp ortance of the complexication of the real Lie groupsfor instance in the structure theory and representation theory of semisimple real Lie groupswe consider here the question on the underlying geometrical -
Patterns of Maximally Entangled States Within the Algebra of Biquaternions
J. Phys. Commun. 4 (2020) 055018 https://doi.org/10.1088/2399-6528/ab9506 PAPER Patterns of maximally entangled states within the algebra of OPEN ACCESS biquaternions RECEIVED 21 March 2020 Lidia Obojska REVISED 16 May 2020 Siedlce University of Natural Sciences and Humanities, ul. 3 Maja 54, 08-110 Siedlce, Poland ACCEPTED FOR PUBLICATION E-mail: [email protected] 20 May 2020 Keywords: bipartite entanglement, biquaternions, density matrix, mereology PUBLISHED 28 May 2020 Original content from this Abstract work may be used under This paper proposes a description of maximally entangled bipartite states within the algebra of the terms of the Creative Commons Attribution 4.0 biquaternions–Ä . We assume that a bipartite entanglement is created in a process of splitting licence. one particle into a pair of two indiscernible, yet not identical particles. As a result, we describe an Any further distribution of this work must maintain entangled correlation by the use of a division relation and obtain twelve forms of biquaternions, attribution to the author(s) and the title of representing pure maximally entangled states. Additionally, we obtain other patterns, describing the work, journal citation mixed entangled states. Finally, we show that there are no other maximally entangled states in Ä and DOI. than those presented in this work. 1. Introduction In 1935, Einstein, Podolski and Rosen described a strange phenomenon, in which in its pure state, one particle behaves like a pair of two indistinguishable, yet not identical, particles [1]. This phenomenon, called by Einstein ’a spooky action at a distance’, has been investigated by many authors, who tried to explain this strange correlation [2–9]. -
Majorana Spinors
MAJORANA SPINORS JOSE´ FIGUEROA-O'FARRILL Contents 1. Complex, real and quaternionic representations 2 2. Some basis-dependent formulae 5 3. Clifford algebras and their spinors 6 4. Complex Clifford algebras and the Majorana condition 10 5. Examples 13 One dimension 13 Two dimensions 13 Three dimensions 14 Four dimensions 14 Six dimensions 15 Ten dimensions 16 Eleven dimensions 16 Twelve dimensions 16 ...and back! 16 Summary 19 References 19 These notes arose as an attempt to conceptualise the `symplectic Majorana{Weyl condition' in 5+1 dimensions; but have turned into a general discussion of spinors. Spinors play a crucial role in supersymmetry. Part of their versatility is that they come in many guises: `Dirac', `Majorana', `Weyl', `Majorana{Weyl', `symplectic Majorana', `symplectic Majorana{Weyl', and their `pseudo' counterparts. The tra- ditional physics approach to this topic is a mixed bag of tricks using disparate aspects of representation theory of finite groups. In these notes we will attempt to provide a uniform treatment based on the classification of Clifford algebras, a work dating back to the early 60s and all but ignored by the theoretical physics com- munity. Recent developments in superstring theory have made us re-examine the conditions for the existence of different kinds of spinors in spacetimes of arbitrary signature, and we believe that a discussion of this more uniform approach is timely and could be useful to the student meeting this topic for the first time or to the practitioner who has difficulty remembering the answer to questions like \when do symplectic Majorana{Weyl spinors exist?" The notes are organised as follows. -
Gauging the Octonion Algebra
UM-P-92/60_» Gauging the octonion algebra A.K. Waldron and G.C. Joshi Research Centre for High Energy Physics, University of Melbourne, Parkville, Victoria 8052, Australia By considering representation theory for non-associative algebras we construct the fundamental and adjoint representations of the octonion algebra. We then show how these representations by associative matrices allow a consistent octonionic gauge theory to be realized. We find that non-associativity implies the existence of new terms in the transformation laws of fields and the kinetic term of an octonionic Lagrangian. PACS numbers: 11.30.Ly, 12.10.Dm, 12.40.-y. Typeset Using REVTEX 1 L INTRODUCTION The aim of this work is to genuinely gauge the octonion algebra as opposed to relating properties of this algebra back to the well known theory of Lie Groups and fibre bundles. Typically most attempts to utilise the octonion symmetry in physics have revolved around considerations of the automorphism group G2 of the octonions and Jordan matrix representations of the octonions [1]. Our approach is more simple since we provide a spinorial approach to the octonion symmetry. Previous to this work there were already several indications that this should be possible. To begin with the statement of the gauge principle itself uno theory shall depend on the labelling of the internal symmetry space coordinates" seems to be independent of the exact nature of the gauge algebra and so should apply equally to non-associative algebras. The octonion algebra is an alternative algebra (the associator {x-1,y,i} = 0 always) X -1 so that the transformation law for a gauge field TM —• T^, = UY^U~ — ^(c^C/)(/ is well defined for octonionic transformations U. -
O/Zp OCTONION ALGEBRA and ITS MATRIX REPRESENTATIONS
Palestine Journal of Mathematics Vol. 6(1)(2017) , 307313 © Palestine Polytechnic University-PPU 2017 O Z OCTONION ALGEBRA AND ITS MATRIX = p REPRESENTATIONS Serpil HALICI and Adnan KARATA¸S Communicated by Ayman Badawi MSC 2010 Classications: Primary 17A20; Secondary 16G99. Keywords and phrases: Quaternion algebra, Octonion algebra, Cayley-Dickson process, Matrix representation. Abstract. Since O is a non-associative algebra over R, this real division algebra can not be algebraically isomorphic to any matrix algebras over the real number eld R. In this study using H with Cayley-Dickson process we obtain octonion algebra. Firstly, We investigate octonion algebra over Zp. Then, we use the left and right matrix representations of H to construct repre- sentation for octonion algebra. Furthermore, we get the matrix representations of O Z with the = p help of Cayley-Dickson process. 1 Introduction Let us summarize the notations needed to understand octonionic algebra. There are only four normed division algebras R, C, H and O [2], [6]. The octonion algebra is a non-commutative, non-associative but alternative algebra which discovered in 1843 by John T. Graves. Octonions have many applications in quantum logic, special relativity, supersymmetry, etc. Due to the non-associativity, representing octonions by matrices seems impossible. Nevertheless, one can overcome these problems by introducing left (or right) octonionic operators and xing the direc- tion of action. In this study we investigate matrix representations of octonion division algebra O Z . Now, lets = p start with the quaternion algebra H to construct the octonion algebra O. It is well known that any octonion a can be written by the Cayley-Dickson process as follows [7]. -
Nilpotent Elements Control the Structure of a Module
Nilpotent elements control the structure of a module David Ssevviiri Department of Mathematics Makerere University, P.O BOX 7062, Kampala Uganda E-mail: [email protected], [email protected] Abstract A relationship between nilpotency and primeness in a module is investigated. Reduced modules are expressed as sums of prime modules. It is shown that presence of nilpotent module elements inhibits a module from possessing good structural properties. A general form is given of an example used in literature to distinguish: 1) completely prime modules from prime modules, 2) classical prime modules from classical completely prime modules, and 3) a module which satisfies the complete radical formula from one which is neither 2-primal nor satisfies the radical formula. Keywords: Semisimple module; Reduced module; Nil module; K¨othe conjecture; Com- pletely prime module; Prime module; and Reduced ring. MSC 2010 Mathematics Subject Classification: 16D70, 16D60, 16S90 1 Introduction Primeness and nilpotency are closely related and well studied notions for rings. We give instances that highlight this relationship. In a commutative ring, the set of all nilpotent elements coincides with the intersection of all its prime ideals - henceforth called the prime radical. A popular class of rings, called 2-primal rings (first defined in [8] and later studied in [23, 26, 27, 28] among others), is defined by requiring that in a not necessarily commutative ring, the set of all nilpotent elements coincides with the prime radical. In an arbitrary ring, Levitzki showed that the set of all strongly nilpotent elements coincides arXiv:1812.04320v1 [math.RA] 11 Dec 2018 with the intersection of all prime ideals, [29, Theorem 2.6]. -
Classifying the Representation Type of Infinitesimal Blocks of Category
Classifying the Representation Type of Infinitesimal Blocks of Category OS by Kenyon J. Platt (Under the Direction of Brian D. Boe) Abstract Let g be a simple Lie algebra over the field C of complex numbers, with root system Φ relative to a fixed maximal toral subalgebra h. Let S be a subset of the simple roots ∆ of Φ, which determines a standard parabolic subalgebra of g. Fix an integral weight ∗ µ µ ∈ h , with singular set J ⊆ ∆. We determine when an infinitesimal block O(g,S,J) := OS of parabolic category OS is nonzero using the theory of nilpotent orbits. We extend work of Futorny-Nakano-Pollack, Br¨ustle-K¨onig-Mazorchuk, and Boe-Nakano toward classifying the representation type of the nonzero infinitesimal blocks of category OS by considering arbitrary sets S and J, and observe a strong connection between the theory of nilpotent orbits and the representation type of the infinitesimal blocks. We classify certain infinitesimal blocks of category OS including all the semisimple infinitesimal blocks in type An, and all of the infinitesimal blocks for F4 and G2. Index words: Category O; Representation type; Verma modules Classifying the Representation Type of Infinitesimal Blocks of Category OS by Kenyon J. Platt B.A., Utah State University, 1999 M.S., Utah State University, 2001 M.A, The University of Georgia, 2006 A Thesis Submitted to the Graduate Faculty of The University of Georgia in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Athens, Georgia 2008 c 2008 Kenyon J. Platt All Rights Reserved Classifying the Representation Type of Infinitesimal Blocks of Category OS by Kenyon J. -
Arxiv:2012.09644V1 [Math.RA] 15 Dec 2020 Oitv -Iesoa Rs.Nnsoitv -Iesoa)Comp Form 8-Dimensional) Norm Nonassociative Associated Whose (Resp
SPLITTING OF QUATERNIONS AND OCTONIONS OVER PURELY INSEPARABLE EXTENSIONS IN CHARACTERISTIC 2 DETLEV W. HOFFMANN Abstract. We give examples of quaternion and octonion division algebras over a field F of characteristic 2 that split over a purely inseparable extension E of F of degree 4 but that do not split over any subextension of F inside E of lower exponent,≥ or, in the case of octonions, over any simple subextension of F inside E. Thus, we get a negative answer to a question posed by Bernhard M¨uhlherr and Richard Weiss. We study this question in terms of the isotropy behaviour of the associated norm forms. 1. Introduction Recall that a quaternion (resp. octonion) algebra A over a field F is a an as- sociative 4-dimensional (resp. nonassociative 8-dimensional) composition algebra whose associated norm form nA is a nondegenerate quadratic form defined on the F -vector space A. This norm form has the property that A is a division algebra iff nA is anisotropic. Furthermore, nA determines A in the sense that if A′ is an- other quaternion (resp. octonion) algebra, then A ∼= A′ as F -algebras iff nA ∼= nA′ (i.e., the norm forms are isometric). There is a vast amount of literature on such algebras. In this note, we consider only base fields of characteristic 2, a case that, compared to characteristic not 2, gives rise to additional subtleties that make the theory in some sense richer but also more intricate and complicated. For example, when conisdering subfields of such algebras one has to distingush between separable and inseparable quadratic extensions. -
Hyperbolicity of Hermitian Forms Over Biquaternion Algebras
HYPERBOLICITY OF HERMITIAN FORMS OVER BIQUATERNION ALGEBRAS NIKITA A. KARPENKO Abstract. We show that a non-hyperbolic hermitian form over a biquaternion algebra over a field of characteristic 6= 2 remains non-hyperbolic over a generic splitting field of the algebra. Contents 1. Introduction 1 2. Notation 2 3. Krull-Schmidt principle 3 4. Splitting off a motivic summand 5 5. Rost correspondences 7 6. Motivic decompositions of some isotropic varieties 12 7. Proof of Main Theorem 14 References 16 1. Introduction Throughout this note (besides of x3 and x4) F is a field of characteristic 6= 2. The basic reference for the staff related to involutions on central simple algebras is [12].p The degree deg A of a (finite dimensional) central simple F -algebra A is the integer dimF A; the index ind A of A is the degree of a central division algebra Brauer-equivalent to A. Conjecture 1.1. Let A be a central simple F -algebra endowed with an orthogonal invo- lution σ. If σ becomes hyperbolic over the function field of the Severi-Brauer variety of A, then σ is hyperbolic (over F ). In a stronger version of Conjecture 1.1, each of two words \hyperbolic" is replaced by \isotropic", cf. [10, Conjecture 5.2]. Here is the complete list of indices ind A and coindices coind A = deg A= ind A of A for which Conjecture 1.1 is known (over an arbitrary field of characteristic 6= 2), given in the chronological order: • ind A = 1 | trivial; Date: January 2008. Key words and phrases.