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Off-Shell Interactions for Closed-String Tachyons
Preprint typeset in JHEP style - PAPER VERSION hep-th/0403238 KIAS-P04017 SLAC-PUB-10384 SU-ITP-04-11 TIFR-04-04 Off-Shell Interactions for Closed-String Tachyons Atish Dabholkarb,c,d, Ashik Iqubald and Joris Raeymaekersa aSchool of Physics, Korea Institute for Advanced Study, 207-43, Cheongryangri-Dong, Dongdaemun-Gu, Seoul 130-722, Korea bStanford Linear Accelerator Center, Stanford University, Stanford, CA 94025, USA cInstitute for Theoretical Physics, Department of Physics, Stanford University, Stanford, CA 94305, USA dDepartment of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India E-mail:[email protected], [email protected], [email protected] Abstract: Off-shell interactions for localized closed-string tachyons in C/ZN super- string backgrounds are analyzed and a conjecture for the effective height of the tachyon potential is elaborated. At large N, some of the relevant tachyons are nearly massless and their interactions can be deduced from the S-matrix. The cubic interactions be- tween these tachyons and the massless fields are computed in a closed form using orbifold CFT techniques. The cubic interaction between nearly-massless tachyons with different charges is shown to vanish and thus condensation of one tachyon does not source the others. It is shown that to leading order in N, the quartic contact in- teraction vanishes and the massless exchanges completely account for the four point scattering amplitude. This indicates that it is necessary to go beyond quartic inter- actions or to include other fields to test the conjecture for the height of the tachyon potential. Keywords: closed-string tachyons, orbifolds. -
H ( Ff^L°9 . INTERNATIONAL CENTRE for \ | THEORETICAL PHYSICS
IC/87/420 H ( ff^l°9 . INTERNATIONAL CENTRE FOR I 'V. ': \| THEORETICAL PHYSICS HARMONIC SUPERSTRING AND COVARIANT QUANTIZATION OF THE GREEN-SCHWARZ SUPERSTRING E. Nissimov S. Pacheva and INTERNATIONAL ATOMIC ENERGY S. Solomon AGENCY UNITED NATIONS EDUCATIONAL, SCIENTIFIC AND CULTURAL ORGANIZATION T T IC/87/420 ABSTRACT International Atomic Energy Agency Based on our recent work, we describe a new generalized model of space- and United Nations Educational Scientific and Cultural Organization time supersymmetric strings - the harmonic superstring. It has the same phys- ical content as the original Green-Schwarz (GS) superstring but it is defined on INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS an enlarged superspace: the D=10 harmonic superspace and incorporates addi- tional fennionic string coordinates. The main feature of the harmonic superstring model is that it contains covariant and irreducible first-class constraints only. This allows for a straight- HARMONIC SUPERSTRING AND COVARIANT QUANTIZATION forward manifestly super-Poincaie'covariant Batalin-Fradkin-Vilkoviski (BFV) OF THE GREEN-SCHWARZ SUPERSTRING * - Becchi-Rouet-Stora-Tyutin (BRST) quantization. The BRST charge has a re- markably simple form and the corresponding BFV hamiltonian exhibits manifest Parisi-Sourlas O5p(l,l|2) symmetry. E. Nissinsov ** In a particular Lorentz-covariant gauge we find the covariant vertex opera- International Centre for Theoretical Physics, Trieste, Italy, tors for the emission of the massless states which closely resemble the covariant "classical" expressions previously guessed by Green and Schwarz. S. Pacheva Institute of Nuclear Research and Nuclear Energy, Boul. Lenin 72, 1784 Sofia, Bulgaria and S. Solomon Physics Department, Weizmann Institute, Hehovot 76100, Israel. MIRAMARE - TRIESTE December 1987 •' To appear in "Perspectives In String Theories" (Proceedings of the Copenhagen Workshop, Denmark, October 1987). -
The Quantized Fermionic String
Class 2: The quantized fermionic string Canonical quantization Light-cone quantization Spectrum of the fermionic string, GSO projection . The super-Virasoro constraints, which allow to eliminate the ghosts, are implemented and analyzed in essentially the same way as in the bosonic string. One new feature is the existence of two sectors: bosonic and fermionic, which have to be studied separately. To remove the tachyon one has to perform the so-called GSO projection, which guarantees space-time supersymmetry of the ten-dimensional theory. There are two possible space-time supersymmetric GSO projections which result in the Type IIA and Type IIB superstring. Summary The fermionic string is quantized analogously to the bosonic string, although now we'll find the critical dimension is 10 . One new feature is the existence of two sectors: bosonic and fermionic, which have to be studied separately. To remove the tachyon one has to perform the so-called GSO projection, which guarantees space-time supersymmetry of the ten-dimensional theory. There are two possible space-time supersymmetric GSO projections which result in the Type IIA and Type IIB superstring. Summary The fermionic string is quantized analogously to the bosonic string, although now we'll find the critical dimension is 10 The super-Virasoro constraints, which allow to eliminate the ghosts, are implemented and analyzed in essentially the same way as in the bosonic string. To remove the tachyon one has to perform the so-called GSO projection, which guarantees space-time supersymmetry of the ten-dimensional theory. There are two possible space-time supersymmetric GSO projections which result in the Type IIA and Type IIB superstring. -
Introduction to Superstring Theory
Introduction to Superstring theory Carmen Nunez Instituto de Astronomia y Física del Espacio C.C. 67 - Sue. 28, 1428 Buenos Aires, Argentina and Physics Department, University of Buenos Aires [email protected] Abstract 1 Overview The bosonic string theory, despite all its beautiful features, has a number of short comings. The most obvious of these are the absence of fermions and the presence of tachyons in spacetime. The tachyon is not an actual physical inconsistency; it indicates at least that the calculations are being performed in an unstable vacuum state. More over, tachyon exchange contributes infrarred divergences in loop diagrams and these divergences make it hard to isolate the ultraviolet behaviour of the "unified quan tum theory" the bosonic string theory gives rise to and determine whether it is really satisfactory. Historically, the solution to the tachyon problem appeared with the solution to the other problem, the absence of fermions. The addition of a new ingredient, supersym- metry on the world-sheet, improves substantially the general picture. In 1977 Gliozzi, Scherk and Olive showed that it was possible to get a model with no tachyons and with equal masses and multiplicities for bosons and fermions. In 1980, Green and Schwarz proved that this model had spacetime supersymmetry. In the completely consisten- t tachyon free form of the superstring theory it was then possible to show that the one-loop diagrams were completely finite and free of ultraviolet divergences. While most workers on the subject believe that the finiteness will also hold to all orders of perturbation theory, complete and universally accepted proofs have not appeared so far. -
Superstrings ETH Proseminar in Theoretical Physics
Neveu{Schwarz{Ramond formulation Modular invariance Green{Schwarz formulation Superstrings ETH Proseminar in Theoretical Physics ImRe Majer May 13th, 2013 ImRe Majer | Superstrings 1/42 Neveu{Schwarz{Ramond formulation Modular invariance Green{Schwarz formulation Outline 1 Neveu{Schwarz{Ramond formulation Building up the spectrum GSO projection 2 Modular invariance Spin structures Partition function 3 Green{Schwarz formulation Supersymmetry Building up the spectrum ImRe Majer | Superstrings 2/42 Neveu{Schwarz{Ramond formulation Modular invariance Green{Schwarz formulation Outline 1 Neveu{Schwarz{Ramond formulation Building up the spectrum GSO projection 2 Modular invariance Spin structures Partition function 3 Green{Schwarz formulation Supersymmetry Building up the spectrum ImRe Majer | Superstrings 3/42 Neveu{Schwarz{Ramond formulation Modular invariance Green{Schwarz formulation NSR action Light cone gauge fixing The Neveu{Schwarz{Ramond action in light cone gauge 1 Z S l:c: = − d 2σ @ X i @αX i − i ¯i ρα@ i NSR 2π α α transverse coordinates i = 1;:::; 8 i is a worldsheet Majorana 2-spinor i is a spacetime vector i SO(8) rotational symmetry =) is an 8v representation of SO(8) ImRe Majer | Superstrings 4/42 Neveu{Schwarz{Ramond formulation Modular invariance Green{Schwarz formulation Building up the spectrum Tools for generating the spectrum Open string or the right-moving part of a closed string. Creation and annihilation operators: i i i X : α−n and αn n 2 Z i i i d−m and dm m 2 Z for R-sector : i i 1 b−r and br r 2 Z + 2 for NS-sector The mass2 operator: X X 1 α0m2 = αi αi + md i d i − for NS-sector −n n −m m 2 n>0 m>0 | {z } | {z } N(α) N(d) 0 2 X i i X i i α m = α−nαn + rb−r br for R-sector n>0 r>0 | {z } | {z } N(α) N(b) ImRe Majer | Superstrings 5/42 Neveu{Schwarz{Ramond formulation Modular invariance Green{Schwarz formulation Building up the spectrum Ground states NSR formulation: All creation/annihilation operators are spacetime vectors. -
PHYS 652: String Theory II Homework 2
PHYS 652: String Theory II Homework 2 Due 2/27/2017 (Assigned 2/15/2017) 1 Heterotic Strings Last semester, you constructed the closed bosonic string by combining left- and right-moving copies of the open bosonic string subject to the level-matching condition. In this class we repeated that construction to obtain the type-II closed superstrings from two copies of the open type-I superstring. In the RNS formalism we employed a GSO projection to remove the tachyon and computed the massless spectrum in lightcone gauge. In the GS formalism spacetime supersymmetry extends the lightcone gauge to superspace and there is no tachyon. Despite the differences between the two formulations, the massless spectra agree. The heterotic strings are closed superstrings obtained by combining the bosonic string for the left-movers with the type-I superstring for the right-movers, again subject to level-matching. Split the 26 coordinates of the critical bosonic string into 10 X's and 16 Y 's and treat the X's as the left-moving side of the spacetime coordinate with the right-moving side identified with the 10 X's of the critical type-I superstring. Using level-matching, construct the massless spectrum in both the RNS and GS formalisms and interpret it in terms of gauge and gravity multiplets. At this point, it is not possible to determine the gauge group of this theory but you can deduce the rank. If, in addition, you were told that the gauge algebra is semi-simple and its dimension is 496, what are the possibilities for the heterotic strings? Why is this string called \heterotic"? 2 Fermionization and Picture Fixing reparameterization-invariance of the bosonic string to conformal gauge requires the in- clusion of the bc ghost system. -
Week 15 1 GSO Projection
Week 15 Reading material • Polchinski, chapter 10, chapter 12 • Becker, Becker, Schwartz, Chapter 4 • Green, Schwartz, Witten, chapter 4,5 1 GSO projection We have seen so far that it is possible to introduce spacetime fermions by using the R-NS formulation of the superstring: we introduce free fermions on the worldsheet. We have also seen that after we bosonize the fermions, we can describe the corresponding (left-moing) vertex operators by X Hj X j V ∼ Ξ ∼ exp(i ± ) exp(−φ/2) = exp(i H ) exp(−φ/2) (1) α 2 2 j j And we can notate the α indices by the combinations of µ pm that appear in the exponential. We also know that ∼ exp(±iHj) for some j. There are a total of 25 choices of signs, giving that a Dirac spinor in ten dimensions has 32 components. If we consider a spacetime fermion, the left mover piece will be a spinor, and the right mover piece should be an integer spin object. The reason for this is that the total spin should be half-integer. If we consider a massless particle, then the right mover piece will be roughly (@X¯ + k ) exp(ikX), and apart from the exponential piece, the conformal field has OPE's with similar conformal operators that go like integer powers of (¯z − w¯)−1. If we consider V+++++ and V−−−−−, we find that their OPE is given by 1 V (z)V (w) ∼ exp(−φ) (2) +++++ −−−−− (z − w)3=2 Remember that the V have conformal dimension one, and that exp(−φ) has conformal dimension equal to one half. -
Notes on Non-Critical Superstrings in Various Dimensions
hep-th/0305197 PUPT-2086 Notes on Non-Critical Superstrings in Various Dimensions Sameer Murthy1 Department of Physics, Princeton University Princeton, NJ 08544, USA Abstract We study non-critical superstrings propagating in d 6 dimensional Minkowski space ≤ or equivalently, superstrings propagating on the two-dimensional Euclidean black hole tensored with d-dimensional Minkowski space. We point out a subtlety in the construction of supersymmetric theories in these backgrounds, and explain how this does not allow a consistent geometric interpretation in terms of fields propagating on a cigar-like spacetime. We explain the global symmetries of the various theories by using their description as the near horizon geometry of wrapped NS5-brane configurations. In the six-dimensional theory, arXiv:hep-th/0305197v1 22 May 2003 we present a CFT description of the four dimensional moduli space and the global O(3) symmetry. The worldsheet action invariant under this symmetry contains both the =2 N sine-Liouville interaction and the cigar metric, thereby providing an example where the two interactions are naturally present in the same worldsheet lagrangian already at the non-dynamical level. May, 2003 1 [email protected] 1. Introduction and summary It has been known for a long time that consistent string theories can live in low number of dimensions. These theories typically develop a dynamical Liouville mode [1] on the worldsheet, and have been called non-critical string theories. These theories can be thought of as Weyl invariant string theories in a spacetime background which is one dimension higher, and contains a varying dilaton and a non-trivial ‘tachyon’ profile which corresponds to the Liouville interaction on the worldsheet. -
String Coherent Vertex Operators of Neveu-Schwarz and Ramond States
Available online at www.sciencedirect.com ScienceDirect Nuclear Physics B 955 (2020) 115050 www.elsevier.com/locate/nuclphysb String coherent vertex operators of Neveu-Schwarz and Ramond states Alice Aldi, Maurizio Firrotta Dipartimento di Fisica, Università di Roma Tor Vergata, I.N.F.N. Sezione di Roma Tor Vergata, Via della Ricerca Scientifica, 1 - 00133 Roma, Italy Received 26 January 2020; received in revised form 5 May 2020; accepted 9 May 2020 Available online 14 May 2020 Editor: Stephan Stieberger Abstract We present a compact expression for a coherent vertex operator in superstring theory, in the Neveu- Schwarz sector, that can be easily extended to the Ramond sector by supersymmetric transformations in target space. We give also an explicit construction for the Ramond coherent vertex operator. These construc- tions provide the use of the supersymmetric version of the Del Giudice-Di Vecchia-Fubini operators and Operator Product Expansion techniques, displaying manifest BRST invariance and after normal ordering also manifest covariance. As a consistency check we compute tree level three-point scattering amplitudes involving Neveu-Schwarz coherent vertex operators in different superghost pictures. Extending these re- sults to the closed superstring, we give the expressions of the coherent vertex operators in the case of type IIA and IIB theories. © 2020 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3. Contents 1. Supersymmetric DDF operators, Spectrum-Generating-Algebra and coherent vertex operators . 3 1.1. OPE construction of general massive vertex operator........................ -
10 the Worldsheet Theory of Superstrings
10 The worldsheet theory of superstrings 10.1 The supersymmetric Polyakov action We begin by constructing a version of the Polyakov action with local (1, 1) supersymmetry 3 on the worldsheet. The metric field gab is accompanied by the spin 2 gravitino field χa↵, µ 1 whereas the embedding coordinate field X is accompanied by a set of spin 2 fermion fields µ ↵.TheEuclideanactionis 1 2 1 ab µ µ a b a µ 1 1 S = d σpg g @aX @bXµ + Γ @a µ (χaΓ Γ ) @bXµ χb µ 4⇡ ↵0 − p↵0 − 4 Z ✓ ◆(10.1) Here the 2D spinor convention is the Euclidean version of the convention described in section 3.4. The action (10.1) is subject to a number of gauge symmetries: di↵eomorphism, local supersymmetry (super-di↵eomorphism), Weyl symmetry, and super-Weyl symmetry. The local supersymmetry transformation takes the form i i δe a = "Γ χa,δgab = "(Γaχb +Γbχa), 1 δχ =2 spin" + (χ Γ Γbχ )(Γij"), a ra 4 a ij b µ µ (10.2) δX = p↵0" , 1 1 µ = @ Xµ χ µ Γa", p a − 2 a ✓ ↵0 ◆ where the supersymmetry generating parameter "(σ)isafermionicspinorfield,and spin is ra the spin connection defined in (3.68). µ 1 The Weyl transformation assigns weight 0 to X ,andweight 2 to χa and µ. Note that µ a the kinetic term for µ is Weyl invariant due to Γ µ =0.Thesuper-Weyltransformatoin i µ µ leaves e a, X ,and invariant, and transforms the gravitino by δχa =Γa⇣ (10.3) for a fermionic spinor field ⇣.Theinvarianceof(10.1)under(10.3)followsfromtheidentities b a b a µ ΓaΓ Γ =0and(ΓΓ )↵(Γb µ)β =0. -
Hep-Th] 13 Oct 2009 2 1 Mi:[email protected] Email: [email protected] E-Mail: .Oe Problems Open 6
GGI Lectures on the Pure Spinor Formalism of the Superstring Oscar A. Bedoyaa1 and Nathan Berkovitsb2 aInstituto de F´ısica, Universidade de S˜ao Paulo 05315-970, S˜ao Paulo, SP, Brasil bInstituto de F´ısica Te´orica, UNESP-Universidade Estadual de S˜ao Paulo 01140-070, S˜ao Paulo, SP, Brasil Notes taken by Oscar A. Bedoya of lectures of Nathan Berkovits in June 2009 at the Galileo Galilei Institute School “New Perspectives in String Theory” Outline 1. Introduction arXiv:0910.2254v1 [hep-th] 13 Oct 2009 2. d = 10 Super Yang-Mills and Superparticle 3. Pure Spinor Superstring and Tree Amplitudes 4. Loop Amplitudes 5. Curved Backgrounds 6. Open Problems 1 e-mail: [email protected] 2 email: [email protected] 1. Introduction 1.1. Ramond-Neveu-Schwarz formalism The superstring in the RNS formalism has four different sectors. In the NS GSO(+) sector, there are the massless vector and massive states while in the NS GSO(−) there are the tachyon and massive modes. On the other hand, in the R GSO(+) sector, there are massless Weyl and massive states, while in the R GSO(−) there are anti-Weyl massless and massive states. Although the GSO projection projects out the GSO(−) part of the spectrum, some processes (such as tachyon condensation) involve this sector. The RNS formalism in the NS GSO(+) and NS GSO(−) sectors is supersymmetric at the worldsheet level. For the open string, it can be described by a superfield in two dimensions Xm(z, κ) = Xm(z) + κψm(z). (1.1) In this formalism, can write vertex operators for the massless field in the GSO(+) sector V = dzdκ(DXm)A (X), (1.2) Z m ∂ ∂ where the derivative is D = ∂κ +κ ∂z . -
String Theory II
Lecture notes String Theory II 136.006 summer term 2009 Maximilian Kreuzer Institut f¨ur Theoretische Physik, TU–Wien +43 – 1 – 58801-13621 Wiedner Hauptstraße 8–10, A-1040 Wien [email protected] http://hep.itp.tuwien.ac.at/˜kreuzer/inc/sst2.pdf Contents 1 Conformal field theory 1 1.1 Theconformalgroup................................... .......... 1 1.2 Wick rotation and Euclidean fields . .......... 3 1.3 Tensors, energy–momentum, and correlations . ........... 7 1.4 First order systems and ghosts . ............ 9 1.5 Operator-state correspondence and vertex operators . ........... 12 1.6 Operator product expansion . ........ 20 1.7 TheWicktheorem ...................................... ........ 25 1.8 Ghost number anomaly and topology . ............ 29 1.9 Ward identities and conformal bootstrap . ............... 35 1.10 Minimal models and chiral algebras . ............ 38 Chapter 1 Conformal field theory Conformal field theory is concerned with quantum field theories that are invariant under con- formal coordinate transformations. Most of the known results refer to two dimensions, where the conformal group is infinite dimensional so that Ward identities strongly constrain the struc- ture of quantum fields and correlation functions. Much of the interest in conformal field theory comes from string theory, but there are also important applications in statistical mechanics and solid state physics, like second order phase transitions of two-dimensional systems and the (fractional) quantum Hall effect [DI97,ga99,cr99]. We first discuss the conformal group in arbitrary dimensions and the Wick rotation with the field content of string theory, which provides the basic examples of free fields. We evaluate the 2-point correlations and discuss the appropriate vacuum states and then proceed to more general concepts and techniques of Euclidean conformal field theory.