BRST and Topological Gauge Theories
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Perturbative Renormalization and BRST
Perturbative renormalization and BRST Michael D¨utsch Institut f¨ur Theoretische Physik Universit¨at Z¨urich CH-8057 Z¨urich, Switzerland [email protected] Klaus Fredenhagen II. Institut f¨ur Theoretische Physik Universit¨at Hamburg D-22761 Hamburg, Germany [email protected] 1 Main problems in the perturbative quantization of gauge theories Gauge theories are field theories in which the basic fields are not directly observable. Field configurations yielding the same observables are connected by a gauge transformation. In the classical theory the Cauchy problem is well posed for the observables, but in general not for the nonobservable gauge variant basic fields, due to the existence of time dependent gauge transformations. Attempts to quantize the gauge invariant objects directly have not yet been completely satisfactory. Instead one modifies the classical action by adding a gauge fixing term such that standard techniques of perturbative arXiv:hep-th/0411196v1 22 Nov 2004 quantization can be applied and such that the dynamics of the gauge in- variant classical fields is not changed. In perturbation theory this problem shows up already in the quantization of the free gauge fields (Sect. 3). In the final (interacting) theory the physical quantities should be independent on how the gauge fixing is done (’gauge independence’). Traditionally, the quantization of gauge theories is mostly analyzed in terms of path integrals (e.g. by Faddeev and Popov) where some parts of the arguments are only heuristic. In the original treatment of Becchi, Rouet and Stora (cf. also Tyutin) (which is called ’BRST-quantization’), a restriction to purely massive theories was necessary; the generalization to the massless case by Lowenstein’s method is cumbersome. -
SUPERSYMMETRY 1. Introduction the Purpose
SUPERSYMMETRY JOSH KANTOR 1. Introduction The purpose of these notes is to give a short and (overly?)simple description of supersymmetry for Mathematicians. Our description is far from complete and should be thought of as a first pass at the ideas that arise from supersymmetry. Fundamental to supersymmetry is the mathematics of Clifford algebras and spin groups. We will describe the mathematical results we are using but we refer the reader to the references for proofs. In particular [4], [1], and [5] all cover spinors nicely. 2. Spin and Clifford Algebras We will first review the definition of spin, spinors, and Clifford algebras. Let V be a vector space over R or C with some nondegenerate quadratic form. The clifford algebra of V , l(V ), is the algebra generated by V and 1, subject to the relations v v = v, vC 1, or equivalently v w + w v = 2 v, w . Note that elements of· l(V ) !can"b·e written as polynomials· in V · and this! giv"es a splitting l(V ) = l(VC )0 l(V )1. Here l(V )0 is the set of elements of l(V ) which can bCe writtenC as a linear⊕ C combinationC of products of even numbers ofCvectors from V , and l(V )1 is the set of elements which can be written as a linear combination of productsC of odd numbers of vectors from V . Note that more succinctly l(V ) is just the quotient of the tensor algebra of V by the ideal generated by v vC v, v 1. -
1 Hamiltonian Quantization and BRST -Survival Guide; Notes by Horatiu Nastase
1 Hamiltonian quantization and BRST -survival guide; notes by Horatiu Nastase 1.1 Dirac- first class and second class constraints, quan- tization Classical Hamiltonian Primary constraints: φm(p; q) = 0 (1) imposed from the start. The equations of motion on a quantity g(q; p) are g_ = [g; H]P:B: (2) Define φm ∼ 0 (weak equality), meaning use the constraint only at the end of the calculation, then for consistency φ_m ∼ 0, implying [φm; H]P:B: ∼ 0 (3) The l.h.s. will be however in general a linearly independent function (of φm). If it is, we can take its time derivative and repeat the process. In the end, we find a complete set of new constrains from the time evolution, called secondary constraints. Together, they form the set of constraints, fφjg; j = 1; J. A quantity R(q; p) is called first class if [R; φj]P:B: ∼ 0 (4) for all j=1, J. If not, it is called second class. Correspondingly, constraints are also first class and second class, independent of being primary or sec- ondary. To the Hamiltonian we can always add a term linear in the constraints, generating the total Hamiltonian HT = H + umφm (5) where um are functions of q and p. The secondary constraint equations are [φm; HT ] ∼ [φm; H] + un[φm; φn] ∼ 0 (6) where in the first line we used that [un; φm]φn ∼ 0. The general solution for um is um = Um + vaVam (7) with Um a particular solution and Vam a solution to Vm[φj; φm] = and va arbitrary functions of time only. -
Equivariant De Rham Cohomology and Gauged Field Theories
Equivariant de Rham cohomology and gauged field theories August 15, 2013 Contents 1 Introduction 2 1.1 Differential forms and de Rham cohomology . .2 1.2 A commercial for supermanifolds . .3 1.3 Topological field theories . .5 2 Super vector spaces, super algebras and super Lie algebras 11 2.1 Super algebras . 12 2.2 Super Lie algebra . 14 3 A categorical Digression 15 3.1 Monoidal categories . 15 3.2 Symmetric monoidal categories . 17 4 Supermanifolds 19 4.1 Definition and examples of supermanifolds . 19 4.2 Super Lie groups and their Lie algebras . 23 4.3 Determining maps from a supermanifold to Rpjq ................ 26 5 Mapping supermanifolds and the functor of points formalism 31 5.1 Internal hom objects . 32 5.2 The functor of points formalism . 34 5.3 The supermanifold of endomorphisms of R0j1 .................. 36 5.4 Vector bundles on supermanifolds . 37 5.5 The supermanifold of maps R0j1 ! X ...................... 41 5.6 The algebra of functions on a generalized supermanifold . 43 1 1 INTRODUCTION 2 6 Gauged field theories and equivariant de Rham cohomology 47 6.1 Equivariant cohomology . 47 6.2 Differential forms on G-manifolds. 49 6.3 The Weil algebra . 53 6.4 A geometric interpretation of the Weil algebra . 57 1 Introduction 1.1 Differential forms and de Rham cohomology Let X be a smooth manifold of dimension n. We recall that Ωk(X) := C1(X; ΛkT ∗X) is the vector space of differential k-forms on X. What is the available structure on differential forms? 1. There is the wedge product Ωk(M) ⊗ Ω`(M) −!^ Ωk+`(X) induced by a vector bundle homomorphism ΛkT ∗X ⊗ Λ`T ∗X −! Λk+`T ∗X ∗ Ln k This gives Ω (X) := k=0 Ω (X) the structure of a Z-graded algebra. -
Topics in Algebraic Supergeometry Over Projective Spaces
Dipartimento di Matematica \Federigo Enriques" Dottorato di Ricerca in Matematica XXX ciclo Topics in Algebraic Supergeometry over Projective Spaces MAT/03 Candidato: Simone Noja Relatore: Prof. Bert van Geemen Correlatore: Prof. Sergio Luigi Cacciatori Coordinatore di Dottorato: Prof. Vieri Mastropietro A.A. 2016/2017 Contents Introduction 4 1 Algebraic Supergeometry 8 1.1 Main Definitions and Fundamental Constructions . .8 1.2 Locally-Free Sheaves on a Supermanifold and Even Picard Group . 14 1.3 Tangent and Cotangent Sheaf of a Supermanifold . 16 1.4 Berezinian Sheaf, First Chern Class and Calabi-Yau Condition . 21 2 Supergeometry of Projective Superspaces 24 2.1 Cohomology of O n|m ` ................................. 24 P p q n|m 2.2 Invertible Sheaves and Even Picard Group Pic0pP q ................ 26 2.3 Maps and Embeddings into Projective Superspaces . 31 2.4 Infinitesimal Automorphisms and First Order Deformations . 32 2.4.1 Supercurves over P1 and the Calabi-Yau Supermanifold P1|2 ......... 35 2.5 P1|2 as N “ 2 Super Riemann Surface . 37 2.6 Aganagic-Vafa's Mirror Supermanifold for P1|2 .................... 41 3 N “ 2 Non-Projected Supermanifolds over Pn 45 3.1 Obstruction to the Splitting of a N “ 2 Supermanifold . 45 3.2 N “ 2 Non-Projected Supermanifolds over Projective Spaces . 49 3.3 Non-Projected Supermanifolds over P1 ......................... 50 1 3.3.1 Even Picard Group of P!pm; nq ......................... 52 1 3.3.2 Embedding of P!p2; 2q: an Example by Witten . 54 3.4 Non-Projected Supermanifolds over P2 ......................... 56 2 3.4.1 P!pFM q is a Calabi-Yau Supermanifold . -
Superfield Equations in the Berezin-Kostant-Leites Category
Superfield equations in the Berezin-Kostant-Leites category Michel Egeileh∗ and Daniel Bennequin† ∗Conservatoire national des arts et m´etiers (ISSAE Cnam Liban) P.O. Box 113 6175 Hamra, 1103 2100 Beirut, Lebanon E-mail: [email protected] †Institut de Math´ematiques de Jussieu-Paris Rive Gauche, Bˆatiment Sophie Germain, 8 place Aur´elie Nemours, 75013 Paris, France E-mail: [email protected] Abstract Using the functor of points, we prove that the Wess-Zumino equations for massive chiral superfields in dimension 4|4 can be represented by supersymmetric equations in terms of superfunctions in the Berezin-Kostant-Leites sense (involving ordinary fields, with real and complex valued components). Then, after introducing an appropriate supersymmetric extension of the Fourier transform, we prove explicitly that these su- persymmetric equations provide a realization of the irreducible unitary representations with positive mass and zero superspin of the super Poincar´egroup in dimension 4|4. 1 Introduction From the point of view of quantum field theory, 1-particle states of a free elementary par- ticle constitute a Hilbert space which, by the requirement of relativistic invariance, must carry an irreducible unitary representation of the Poincar´egroup V ⋊ Spin(V ), where V is a Lorentzian vector space. In signature (1, 3), it is well-known since [Wig] that the irreducible representations of the Poincar´egroup that are of physical interest are classified 1 3 by a nonnegative real number m (the mass), and a half-integer s ∈ {0, 2 , 1, 2 , ...} (the spin)1. It is also known, cf. [BK], that all the irreducible unitary representations of the Poincar´e group of positive (resp. -
Quotient Supermanifolds
BULL. AUSTRAL. MATH. SOC. 58A50 VOL. 58 (1998) [107-120] QUOTIENT SUPERMANIFOLDS CLAUDIO BARTOCCI, UGO BRUZZO, DANIEL HERNANDEZ RUIPEREZ AND VLADIMIR PESTOV A necessary and sufficient condition for the existence of a supermanifold structure on a quotient defined by an equivalence relation is established. Furthermore, we show that an equivalence relation it on a Berezin-Leites-Kostant supermanifold X determines a quotient supermanifold X/R if and only if the restriction Ro of R to the underlying smooth manifold Xo of X determines a quotient smooth manifold XQ/RQ- 1. INTRODUCTION The necessity of taking quotients of supermanifolds arises in a great variety of cases; just to mention a few examples, we recall the notion of supergrassmannian, the definition of the Teichmiiller space of super Riemann surfaces, or the procedure of super Poisson reduction. These constructions play a crucial role in superstring theory as well as in supersymmetric field theories. The first aim of this paper is to prove a necessary and sufficient condition ensuring that an equivalence relation in the category of supermanifolds gives rise to a quotient supermanifold; analogous results, in the setting of Berezin-Leites-Kostant (BLK) super- manifolds, were already stated in [6]. Secondly and rather surprisingly at that, it turns out that for Berezin-Leites-Kostant supermanifolds any obstacles to the existence of a quotient supermanifold can exist only in the even sector and are therefore purely topological. We demonstrate that an equivalence relation Ron a. BLK supermanifold X determines a quotient BLK supermanifold X/R if and only if the restriction of R to the underlying manifold Xo of X determines a quotient smooth manifold. -
Propagators and Path Integrals
NAT10NAAI. WSTITUUT VOOR KERNFYSICA EN NIKHEF-H/95-050 Propagators and Path Integrals J.W. van Holten NIKHEF-H, P.O. Box 41882 1009 DB Amsterdam NI, August 22, 1995 Abstract Path-integral expressions for one-particle propagators in scalar and ferinioaic field theories are derived, for arbitrary mass. This establishes a direct connection between field theory and specific classical point-particle models. The role of world-line rep&rametroation invaiiance of the classical action avnd the implementation of the corresponding BB5T-symmetry in the qutntuin theory are discussed. The presence of classical world-line supersymrnetry is shown to lead t/> an unwanted doubling of states for massive spin-1/2 particles. The origin of this phenomenon is traced to a 'hidden' topologies! fermionic excitation. A different formulation of the pseudo-classical mechan- ics using a bosonic representation of 71 is shown to remove those extra states at the expense of losing manifest supersymmetry. PilKHEf SECTIE - H POSTBUS 4188',!, 1009 DB A^STERDfW •UL ? 0 NJ 0 1 KS002045549 R: FI NL96FG754 DEOOSS87924 1 Introduction Because of their conceptual simplicity, path-integral methods [1, 2] often provide convenient procedures to obtain insight in field theoretical problems. In recent work by Strassler, McKeon, Schmidt, Schubert and others [3]-[7] world-line path integrals have been applied to a reformulation of standard Feynman perturbation theory from which useful information on the structure of perturbative Green's functions is extracted. Some of these results were actually first derived in the particle-limit of string theory [8]. A basic question in this context is the representation of propagators in quantum field theory by path integrals for relativistic particles of various kind. -
Torsion Constraints in Supergeometry
Commun. Math. Phys. 133, 563-615(1990) Communications ΪΠ Mathematical Physics ©Springer-Verlagl990 Torsion Constraints in Supergeometry John Lott* I.H.E.S., F-91440 Bures-sur-Yvette, France Received November 9, 1989; in revised form April 2, 1990 Abstract. We derive the torsion constraints for superspace versions of supergravity theories by means of the theory of G-stmctures. We also discuss superconformal geometry and superKahler geometry. I. Introduction Supersymmetry is a now well established topic in quantum field theory [WB, GGRS]. The basic idea is that one can construct actions in ordinary spacetime which involve both even commuting fields and odd anticommuting fields, with a symmetry which mixes the two types of fields. These actions can then be interpreted as arising from actions in a superspace with both even and odd coordinates, upon doing a partial integration over the odd coordinates. A mathematical framework to handle the differential topology of supermanifolds, manifolds with even and odd coordinates, was developed by Berezin, Kostant and others. A very readable account of this theory is given in the book of Manin [Ma]. The right notion of differential geometry for supermanifolds is less clear. Such a geometry is necessary in order to write supergravity theories in superspace. One could construct a supergeometry by ΊL2 grading what one usually does in (pseudo) Riemannian geometry, to have supermetrics, super Levi-Civita connections, etc. The local frame group which would take the place of the orthogonal group in standard geometry would be the orthosymplectic group. However, it turns out that this would be physically undesirable. Such a program would give more fields than one needs for a minimal supergravity theory, i.e. -
BRST Quantization of Yang-Mills Theory: a Purely Hamiltonian Approach on Fock Space
PHYSICAL REVIEW D 97, 074006 (2018) BRST quantization of Yang-Mills theory: A purely Hamiltonian approach on Fock space Hans Christian Öttinger* ETH Zürich, Department of Materials, Polymer Physics, HCP F 47.2, CH-8093 Zürich, Switzerland (Received 1 March 2018; published 3 April 2018) We develop the basic ideas and equations for the BRST quantization of Yang-Mills theories in an explicit Hamiltonian approach, without any reference to the Lagrangian approach at any stage of the development. We present a new representation of ghost fields that combines desirable self-adjointness properties with canonical anticommutation relations for ghost creation and annihilation operators, thus enabling us to characterize the physical states on a well-defined Fock space. The Hamiltonian is constructed by piecing together simple BRST invariant operators to obtain a minimal invariant extension of the free theory. It is verified that the evolution equations implied by the resulting minimal Hamiltonian provide a quantum version of the classical Yang-Mills equations. The modifications and requirements for the inclusion of matter are discussed in detail. DOI: 10.1103/PhysRevD.97.074006 I. INTRODUCTION The purpose of this paper is to show in the context of BRST quantization is a pivotal tool in developing Yang-Mills theories how all the above facets can be theories of the fundamental interactions, where the acro- handled entirely within the Hamiltonian approach, where nym BRST refers to Becchi, Rouet, Stora [1] and Tyutin explicit constructions on a suitable Fock space allow for a [2]. This method for handling constraints in the quantiza- maximum of intuition. The focus on Fock space implies a (quantum) particle interpretation rather than a field tion of field theories usually requires a broad viewpoint idealization. -
BRST Formulation of the Gupta-Bleuler Quantization Method
NL90C0266 MATIONAAL INSTITUUT VOOR KERNFYSICA EN HOCE-EMERGIEFYSICA March 1990 NIKHEF-H/90-7 BRST Formulation of the Gupta-Bleuler Quantization Method Z. Hastowicz *, J. Kowalski-Glikman \ J. Lukierski *. J.W, van Hotten t Abstract In this paper we show, how an algebra of mixed flits and second class constrain»» can ba transformed Into an algebra of the Gupta-Bleuler type, consisting of holomorphlc ar.d anti* hotomorphic constraints. We perform its quantization by BRST methods. We construct a second* level BRST operator n by Introducing a new ghost sector (the second-level ghosts), in addition to the ghosts of the standard BRST operator. We find an Inner product In this ghost sector such that the operator li ts hermltean. The physical states, as defined by the non-hermitsan holomorphlc constraints, are shown to be given in terms of the cohomology of this hermitean BRST charge. * Mstttuf tor TtwofHemt Pttyttca. UMvmrtlty of Wrodmw. ut Cybutokltgo «. Wnetmw. Poimnd • CHEAP, PO BOM 4IM?, 1009 DB Amstfdmm. Th» Nethftmnda. bit/ft rt00J)/fcf>«M.flSM»*itf f NSOHEF^ PO BOM 41*62. 1009 OB Amstontom. Thm Netherlands, bitnét 11ë&nikh*tli.nikh*t.nl NIKHEF SECTIE-H POSTBUS 41H3, 100» L«B AMSTERDAM 1 Introduction BRST-methods [1, 2} have become a powerful tool in the quantization of constrained systems. Not only do they provide a method for establishing the consistency of the covariant quantization procedure of gauge theories , such as used in the path-integral formulation of Yang-Mills theory [3], they also have become important in the elucidation of the canonical structure of constrained systems [4, 5, 6, 7] like relativistic point-particles and strings |8], In spite of all the past successes of the method, there still doesn't exist a completely unified and unique prescription for the application of BUST' methods to arbitrary constrained systems and surprises keep turning up when studying new systems with new types of gauge-invariances. -
2. the Concept of a Supermanifold
2. THE CONCEPT OF A SUPERMANIFOLD 2.1. Geometry of physical space. 2.2. The mathematical evolution of the concept of space as a geometrical ob- ject. 2.3. Geometry and algebra. 2.4. Supermanifolds and their supersymmetries. 2.1. Geometry of physical space. Someone who is already familiar with the theory of differentiable manifolds or algebraic varieties can be very quickly intro- duced to the notion of a supermanifold and the concept of supersymmetry. Just as the manifolds and varieties are defined by first starting with local pieces on which the coordinate functions are defined, and then gluing these local pieces together, a supermanifold may be defined as a space on which locally one has coordinates x1; : : : ; xn; θ1; : : : θr where the xi are the usual commuting coordinates and the θj, the anticommuting (fermionic) coordinates, with the various sets of local chats be- ing related by transformations of the appropriate smoothness type. Everything is then done exactly as in the classical theory. Supersymmetries are diffeomorphisms of such spaces and these form super Lie groups. One can construct a theory of differentiation and integration on such spaces and write down equations of motions of particles and fields starting from suitable Lagrangians. If one starts with a super- symmetric Lagrangian then one obtains an action of the supersymmetric group on the solutions of the field equations thus defined. The stage on which supersymmetic quantum field theory lives is then a super spacetime, either flat or curved. How- ever, such a treatment, in spite of being very practical and having the advantage of getting into the heart of matters very quickly, does not do full justice either to the understanding of the concepts at a deeper level or to comprehending the boldness of the generalization of conventional geometry that is involved here.