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hep-th/9110054
Generalized Duality and Singular Strings in Higher Dimensions
Deformations of gauged WZW actions are constructed for any pair $(G,H)$ by taking different embeddings of the gauge group $H\subset G$ as it acts on the left and right of the group element $g$. This leads to models that are dual to each other, generalizing the axial/vector duality of the two dimensional black hole manifold. The classical equations are completely solved for any pair $(G,H)$ and in particular for the anti de Sitter string based on $SO(d- 1,2)/SO(d-1,1)$ for which the normal modes are determined. Duality is demonstrated for models that have the same set of normal modes. Concentrating on $SO(2,2)/SO(2,1)$, the metric and dilaton fields of the $d=3$ string as well as some of the dual generalizations are obtained. They have curvature singularities and represent new singular solutions of Einstein's general relativity in three dimensions.
1991-10-18
2009-10-22
[ "hep-th" ]
I. Bars and K. Sfetsos
hep-th/9110051
Instantons in the Quantum Framework of 2D Gravity
We analyze the non--perturbative features of 2D quantum gravity defined by stochastic regularization of the unstable matrix model showing, first, that the WKB approximation of the well-defined quantum Fokker-Planck hamiltonian corresponds to the semiclassical eigenvalue density of the former. The double scaled potential exhibits an instanton--like behaviour, which is universal and scales, but whose interpretation in terms of pure gravity is still open.
1991-10-18
2008-02-03
[ "hep-th" ]
J. Luis Miramontes and Joaquin Sanchez Guillen
hep-th/9110052
Structure Constants of the Fractional Supersymmetry Chiral Algebras
The fractional supersymmetry chiral algebras in two-dimensional conformal field theory are extended Virasoro algebras with fractional spin currents. We show that associativity and closure of these algebras determines their structure constants in the case that the Virasoro algebra is extended by precisely one current. We compute the structure constants of these algebras explicitly and we show that correlators of the currents satisfy non-Abelian braiding relations.
1991-10-18
2009-10-22
[ "hep-th" ]
P.C.Argyres, J.M.Grochocinski, S.-H.H.Tye
hep-th/9110050
Analytical Bethe Ansatz for Quantum-Algebra-Invariant Spin Chains
We have recently constructed a large class of open quantum spin chains which have quantum-algebra symmetry and which are integrable. We show here that these models can be exactly solved using a generalization of the analytical Bethe Ansatz (BA) method. In particular, we determine in this way the spectrum of the transfer matrices of the $U_q [(su(2)]$-invariant spin chains associated with $A^{(1)}_1$ and $A^{(2)}_2$ in the fundamental representation. The quantum-algebra invariance of these models plays an essential role in obtaining these results. The BA equations for these open chains are ``doubled'' with respect to the BA equations for the corresponding closed chains.
1991-10-17
2014-11-18
[ "hep-th" ]
Luca Mezincescu and Rafael I. Nepomechie
hep-th/9110047
Rg Flows in the $D$-Series of Minimal Cfts
Using results of the thermodynamic Bethe Ansatz approach and conformal perturbation theory we argue that the $\phi_{1,3}$-perturbation of a unitary minimal $(1+1)$-dimensional conformal field theory (CFT) in the $D$-series of modular invariant partition functions induces a renormalization group (RG) flow to the next-lower model in the $D$-series. An exception is the first model in the series, the 3-state Potts CFT, which under the $\ZZ_2$-even $\phi_{1,3}$-perturbation flows to the tricritical Ising CFT, the second model in the $A$-series. We present arguments that in the $A$-series flow corresponding to this exceptional case, interpolating between the tetracritical and the tricritical Ising CFT, the IR fixed point is approached from ``exactly the opposite direction''. Our results indicate how (most of) the relevant conformal fields evolve from the UV to the IR CFT.
1991-10-17
2009-10-22
[ "hep-th" ]
Timothy R. Klassen and Ezer Melzer
hep-th/9110044
(Super-) String in Two Dimensional Black Hole and Target Space Dualities
We review the recently proposed string theory in two dimensional black hole background. Especially, the structure of the duality in the target space is discussed. The duality is analogous to \lq\lq $R \rightarrow 1/R$" symmetry of a compactified boson. We consider the duality in more general target space manifolds which have Killing symmetries and we give an explicit formula which connects two different manifolds which are dual to each other. Superstring theory in two dimensional black hole background is also discussed based on supersymmetric $SU(1,1)/U(1)$ gauged Wess-Zumino-Witten model.
1991-10-17
2008-11-26
[ "hep-th" ]
Shin'ichi Nojiri
hep-th/9110049
Exactly Solved Models with Quantum Algebra Symmetry
We have constructed and solved various one-dimensional quantum mechanical models which have quantum algebra symmetry. Here we summarize this work, and also present new results on graded models, and on the so-called string solutions of the Bethe Ansatz equations for the $A^{(2)}_2$ model.
1991-10-17
2007-05-23
[ "hep-th" ]
Luca Mezincescu and Rafael I. Nepomechie
hep-th/9110048
Topological Field Theory and Rational Curves
We analyze the superstring propagating on a Calabi-Yau threefold. This theory naturally leads to the consideration of Witten's topological non-linear sigma-model and the structure of rational curves on the Calabi-Yau manifold. We study in detail the case of the world-sheet of the string being mapped to a multiple cover of an isolated rational curve and we show that a natural compactification of the moduli space of such a multiple cover leads to a formula in agreement with a conjecture by Candelas, de la Ossa, Green and Parkes.
1991-10-17
2015-06-26
[ "hep-th" ]
Paul S. Aspinwall and David R. Morrison
hep-th/9110045
Hamiltonian Reduction of Super Osp(1,2)} and Sl(2,1) Kac-Moody Algebras
We present the Wakimoto construction of the super OSp(1,2) and SL(2,1) Kac-Moody algebras and the free field representation of the corresponding WZW models. After imposing suitable constraints, we can lead the Feigin-Fuchs representation of Virasoro algebras and coadjoint actions ofthe N=1 and N=2 conformal symmetries. This formulation corresponds to a supercovariant extension of the Drinfeld and Sokolov Hamiltonian reduction.
1991-10-16
2011-04-20
[ "hep-th" ]
Kazuhiro Kimura
hep-th/9110046
Phase Diagram of the Dissipative Hofstadter Model
The dissipative quantum mechanics of a charged particle in a uniform magnetic field and periodic potential has delocalization critical points which correspond to backgrounds for the open string. We study the phase diagram of this system (in the magnetic field/dissipation constant plane) and find a fractal structure which, in the limit of zero dissipation, matches the fractal energy level structure of the pure quantum mechanical version of this problem (Hofstadter model).
1991-10-16
2019-08-14
[ "hep-th" ]
Curtis G. Callan, Jr. and Denise Freed
hep-th/9110039
Cosets as gauge slices in SU(1,1) strings
We consider a string theory based on an SU(1,1) Wess-Zumino-Novikov-Witten model and an arbitrary unitary conformal fild theory. We show that the solutions of the Virasoro conditions, in the unitarity regime of the SU(1,1) theory, are states which lie in the Euclidean coset SU(1,1)/U(1). This shows the validity, at the quantum level, of a time-like type of gauge in these models.
1991-10-15
2009-10-22
[ "hep-th" ]
Stephen Hwang
hep-th/9110037
Hard Art of the Universe Creation
We develop a stochastic approach to the theory of tunneling with the baby universe formation. This method is applied also to the theory of creation of the universe in a laboratory.
1991-10-15
2009-09-29
[ "hep-th" ]
Andrei Linde
hep-th/9110038
Gauge and General Coordinate Invariance in Non-Polynomial Closed String Field Theory
An appropriate field configuration in non-polynomial closed string field theory is shown to correspond to a general off-shell field configuration in low energy effective field theory. A set of string field theoretic symmetries that act on the fields in low energy effective field theory as general coordinate transformation and antisymmetric tensor gauge transformation is identified. The analysis is carried out to first order in the fields; thus the symmetry transformations in string field theory reproduce the linear and the first non-linear terms in the gauge transformations in the low energy effective field theory.
1991-10-15
2009-09-15
[ "hep-th" ]
Debashis Ghoshal and Ashoke Sen
hep-th/9110040
S-matrix of N=2 Supersymmetric Sine-Gordon Theory
We investigate the S-matrix of N=2 supersymmetric sine-Gordon theory based on the N=2 supersymmetry and the quantum group structure. The topological charges play an important role to derive physical contents.
1991-10-15
2009-10-22
[ "hep-th" ]
Ken-ichiro Kobayashi and Tsuneo Uematsu
hep-th/9110041
Some Properties of (Non) Critical Strings
We review some recent developments in string theory, emphasizing the importance of vacuum instabilities, their relation to the density of states, and the role of space-time fermions in non-critical string theory. We also discuss the classical dynamics of two dimensional string theory.
1991-10-15
2007-05-23
[ "hep-th" ]
D. Kutasov
hep-th/9110043
Copernican Crystallography
Redundancies are pointed out in the widely used extension of the crystallographic concept of Bravais class to quasiperiodic materials. Such pitfalls can be avoided by abandoning the obsolete paradigm that bases ordinary crystallography on microscopic periodicity. The broadening of crystallography to include quasiperiodic materials is accomplished by defining the point group in terms of indistinguishable (as opposed to identical) densities.
1991-10-15
2009-01-23
[ "hep-th" ]
N. David Mermin (Laboratory of Atomic and Solid State Physics Cornell University, Ithaca, NY 14853-2501)
hep-th/9110042
K\"ahler-Chern-Simons Theory
K\"ahler-Chern-Simons theory describes antiself-dual gauge fields on a four- dimensional K\"ahler manifold. The phase space is the space of gauge potentials, the symplectic reduction of which by the constraints of antiself-duality leads to the moduli space of antiself-dula instantons. We outline the theory highlighting the symmetries, their canonical realization and some properties of the quantum wave functions. The relationship to integrable systems via dimensional reduction is briefly discussed.
1991-10-15
2007-05-23
[ "hep-th" ]
V.P.Nair (Columbia University)
hep-th/9110035
Superspace WZW Models and Black Holes
We show how to write an off-shell action for the $SU(2)\times U(1)$ supersymmetric WZW model in terms of $N=2$ chiral and twisted chiral multiplets. We discuss the $N=4$ supersymmetry of this model and exhibit the $N=4$ superconformal current algebra. Finally, we show that the off-shell formulation makes it possible to perform a duality transformation, which leads to a supersymmetric sigma model on a manifold with a black hole type singularity.
1991-10-14
2007-05-23
[ "hep-th" ]
Changhyun Ahn, Martin Rocek, Kareljan Schoutens and Alexander Sevrin
hep-th/9110034
Open String Theory in 1+1 Dimensions
We show that tree level open two dimensional string theory is exactly solvable; the solution exhibits some unusual features, and is qualitatively different from the closed case. The open string ``tachyon'' S -- matrix describes free fermions, which can be interpreted as the quarks at the ends of the string. These ``quarks'' live naturally on a lattice in space-time. We also find an exact vacuum solution of the theory, corresponding to a charged black hole.
1991-10-14
2010-11-01
[ "hep-th" ]
M. Bershadsky and D. Kutasov
hep-th/9110036
Flipped SU(5): Origins and Recent Developments
We present an account of the early developments that led to the present form of the flipped $SU(5)$ string model. We focus on the method used to decide on this particular string model, as well as the basic steps followed in constructing generic models in the free fermionic formulation of superstrings in general and flipped $SU(5)$ in particular. We then describe the basic calculable features of the model which are used to obtain its low-energy spectrum: doublet and triplet Higgs mass matrices, fermion Yukawa matrices, neutrino masses, and the top-quark mass. We also review the status of proton decay in the model, as well as the hidden sector bound states called cryptons. Finally, we comment on the subject of string threshold corrections and string unification.
1991-10-14
2007-05-23
[ "hep-th" ]
J. Lopez and D. Nanopoulos
hep-th/9110033
Anomaly-free $W$-gravity Theories
We give a review of some recent developments in the quantisation of $W$-gravity theories. In particular, we discuss the construction of anomaly-free $W_\infty$ and $W_3$ gravities.
1991-10-13
2007-05-23
[ "hep-th" ]
C.N. Pope
hep-th/9110031
BRST Analysis of Physical States for 2D (Super) Gravity Coupled to (Super) Conformal Matter
We summarize some recent results on the BRST analysis of physical states of 2D gravity coupled to c<=1 conformal matter and the supersymmetric generalization.
1991-10-12
2009-10-22
[ "hep-th" ]
P. Bouwknegt, J. McCarthy and K. Pilch
hep-th/9110027
Classical W-symmetry and Grassmannian Manifold
Classical W-symmetry is globally parametrized by the Grassmannian Manifold which is associated with the non-relativistic fermions. We give the bosonization rule which defines the natural higher coordinates system to describe the W-geometry. Generators of the W-algebra can be obtained from a single tau-function by using vertex operators.
1991-10-11
2009-10-22
[ "hep-th" ]
Yutaka Matsuo
hep-th/9110030
Correlation Functions of Local Operators in 2D Gravity Coupled to Minimal Matter
Recent advances are being discussed on the calculation, within the conformal field theory approach, of the correlation functions for local operators in the theory of 2D gravity coupled to the minimal models of matter.
1991-10-11
2007-05-23
[ "hep-th" ]
Vl.S.Dotsenko
hep-th/9110029
Correlators of Special States in c=1 Liouville Theory
We generalize the ground ring structure to all special BRST invariant operators in the right branch in the c=1 Liouville theory. We also discuss correlation functions of special states on the sphere.
1991-10-11
2009-10-22
[ "hep-th" ]
Miao Li
hep-th/9110028
W-Geometries
It is shown that, classically, the W-algebras are directly related to the extrinsic geometry of the embedding of two-dimensional manifolds with chiral parametrisation (W-surfaces) into higher dimensional K\"ahler manifolds. We study the local and the global geometries of such embeddings, and connect them to Toda equations. The additional variables of the related KP hierarchy are shown to yield a specific coordinate system of the target-manifold, and this allows us to prove that W-transformations are simply particular diffeomorphisms of this target space. The W-surfaces are shown to be instantons of the corresponding non-linear $\sigma$-models.
1991-10-11
2009-10-22
[ "hep-th" ]
Jean-Loup Gervais, Yutaka Matsuo
hep-th/9110032
Comments on Two-Loop Kac-Moody Algebras
It is shown that the two-loop Kac-Moody algebra is equivalent to a two variable loop algebra and a decoupled $\beta$-$\gamma$ system. Similarly WZNW and CSW models having as algebraic structure the Kac-Moody algebra are equivalent to an infinity of versions of the corresponding ordinary models and decoupled abelian fields.
1991-10-10
2009-10-22
[ "hep-th" ]
L.A.Ferreira, J.F.Gomes, A.Schwimmer and A.H.Zimerman
hep-th/9110026
Effective String Amplitudes for Hadronic Physics
We propose using the general structure and properties of conformal field theory amplitudes, in particular those defined on surfaces with boundaries, to explore effective string theory amplitudes for some hadronic processes. Two examples are considered to illustrate the approach. In one a natural mechanism for chiral symmetry breaking within the string picture is proposed. One consequence is that the vertex operator for pion emission (at zero momentum) behaves like a world sheet current evaluated on the string boundary. This fact is used to rederive, in a more general setting, hadronic mass relations found in the early days of string theory by Lovelace, and Ademollo, Veneziano and Weinberg. In the second example, we derive the general structure of the form factor for the emission of a pomeron (interpreted as a closed string) from a meson or baryon. The result reconciles the interpretation of the pomeron as a closed string, emitted from the interior of the meson or baryon world sheet, with the additive quark rules for total hadronic cross sections. We also review the difficulties involved in constructing complete effective string theories for hadrons, and comment on the relation between the intercepts of trajectories and the short distance behavior of the underlying theory.
1991-10-10
2009-10-22
[ "hep-th" ]
David C. Lewellen
hep-th/9110025
Coadjoint Orbits of the Generalised Sl(2) Sl(3) Kdv Hierarchies
In this paper we develop two coadjoint orbit constructions for the phase spaces of the generalised $Sl(2)$ and $Sl(3)$ KdV hierachies. This involves the construction of two group actions in terms of Yang Baxter operators, and an Hamiltonian reduction of the coadjoint orbits. The Poisson brackets are reproduced by the Kirillov construction. From this construction we obtain a `natural' gauge fixing proceedure for the generalised hierarchies.
1991-10-09
2009-10-22
[ "hep-th", "math.QA" ]
Nigel J. Burroughs
hep-th/9110024
Generalized W-algebras and Integrable Hierarchies
We report on generalizations of the KdV-type integrable hierarchies of Drinfel'd and Sokolov. These hierarchies lead to the existence of new classical $W$-algebras, which arise as the second Hamiltonian structure of the hierarchies. In particular, we present a construction of the $W_n^{(l)}$ algebras.
1991-10-08
2019-08-17
[ "hep-th" ]
N. Burroughs, M. de Groot, T. Hollowood and L. Miramontes
hep-th/9110023
Gauge and Matter Condensates in Realistic String Models
We examine the inter-relationship of the superpotential containing hidden and observable matter fields and the ensuing condensates in free fermionic string models. These gauge and matter condensates of the strongly interacting hidden gauge groups play a crucial role in the determination of the physical parameters of the observable sector. Supplementing the above information with the requirement of modular invariance, we find that a generic model with only trilinear superpotential allows for a degenerate (and sometimes pathological) set of vacua. This degeneracy may be lifted by higher order terms in the superpotential. We also point out some other subtle points that may arise in calculations of this nature. We exemplify our observations by computing explicitly the modular invariant gaugino and matter condensates in the flipped SU(5) string model with hidden gauge group $SO(10)\times SU(4)$.
1991-10-08
2009-10-22
[ "hep-th" ]
S. Kalara, J. Lopez, and D. Nanopoulos
hep-th/9110022
Universal Field Equations with Covariant Solutions D.B. Fairlie
Metric independent $\sigma$ models are constructed. These are field theories which generalise the membrane idea to situations where the target space has fewer dimensions than the base manifold. Instead of reparametrisation invariance of the independent variables, one has invariance of solutions of the field equations under arbitrary functional redefinitions of the field quantities. Among the many interesting properties of these new models is the existence of a hierarchical structure which is illustrated by the following result. Given an arbitrary Lagrangian, dependent only upon first derivatives of the field, and homogeneous of weight one, an iterative procedure for calculating a sequence of equations of motion is discovered, which ends with a universal, possibly integrable equation, which is independent of the starting Lagrangian. A generalisation to more than one field is given.
1991-10-08
2009-10-22
[ "hep-th" ]
J. Govaerts, A. Morozov
hep-th/9110019
Classical Dynamics of Point Particles in 2+1 Gravity
The relation between Einstein gravity and the Chern-Simons gauge theory of the Poincare' group is discussed at the classical level.
1991-10-07
2009-10-22
[ "hep-th" ]
Andrea Cappelli, conference proceedings
hep-th/9110021
Gauge Theory Formulation of the $c=1$ Matrix Model: Symmetries and Discrete States
We present a non-relativistic fermionic field theory in 2-dimensions coupled to external gauge fields. The singlet sector of the $c=1$ matrix model corresponds to a specific external gauge field. The gauge theory is one-dimensional (time) and the space coordinate is treated as a group index. The generators of the gauge algebra are polynomials in the single particle momentum and position operators and they form the group $W^{(+)}_{1+\infty}$. There are corresponding Ward identities and residual gauge transformations that leave the external gauge fields invariant. We discuss the realization of these residual symmetries in the Minkowski time theory and conclude that the symmetries generated by the polynomial basis are not realized. We motivate and present an analytic continuation of the model which realises the group of residual symmetries. We consider the classical limit of this theory and make the correspondence with the discrete states of the $c=1$ (Euclidean time) Liouville theory. We explain the appearance of the $SL(2)$ structure in $W^{(+)}_{1+\infty}$. We also present all the Euclidean classical solutions and the classical action in the classical phase space. A possible relation of this theory to the $N=2$ string theory and also self-dual Einstein gravity in 4-dimensions is pointed out.
1991-10-07
2015-06-26
[ "hep-th" ]
Sumit R.Das, Avinash Dhar, Gautam Mandal and Spenta R.Wadia
hep-th/9110017
Scattering at Planckian Energies
We give a systematic analysis of forward scattering in 3$+$1-dimensional quantum gravity, at center of mass energies comparable or larger than the Planck energy. We show that quantum gravitational effects in this kinematical regime are described by means of a topological field theory. We find that the scattering amplitudes display a universal behaviour very similar to two dimensional string amplitudes, thereby recovering results obtained previously by 't Hooft. Finally, we discuss the two-particle process in some detail.
1991-10-07
2009-10-22
[ "hep-th" ]
Herman Verlinde and Erik Verlinde
hep-th/9110020
Classical Scattering in 2+1 Gravity with N Spinning Sources
The classical dynamics of N spinning point sources in 2+1 Einstein-Cartan gravity is considered. It corresponds to the ISO(2,1) Chern-Simons theory, in which the torsion source is restricted to its intrinsic spin part. A class of explicit solutions is found for the dreibein and the spin connection, which are torsionless in the spinless limit. By using the residual local Poincare' invariance of the solutions, we fix the gauge so that the metric is smooth outside the particles and satisfies proper asymptotic conditions at space and time infinity. We recover previous results for test bodies and find new ones for the scattering of two dynamical particles in the massless limit.
1991-10-07
2009-10-22
[ "hep-th" ]
Andrea Cappelli, Marcello Ciafaloni and Paolo Valtancoli
hep-th/9110016
Self-Gravitating Strings In 2+1 Dimensions
We present a family of classical spacetimes in 2+1 dimensions. Such a spacetime is produced by a Nambu-Goto self-gravitating string. Due to the special properties of three-dimensional gravity, the metric is completely described as a Minkowski space with two identified worldsheets. In the flat limit, the standard string is recovered. The formalism is developed for an open string with massive endpoints, but applies to other boundary conditions as well. We consider another limit, where the string tension vanishes in geometrical units but the end-masses produce finite deficit angles. In this limit, our open string reduces to the free-masses solution of Gott, which possesses closed timelike curves when the relative motion of the two masses is sufficiently rapid. We discuss the possible causal structures of our spacetimes in other regimes. It is shown that the induced worldsheet Liouville mode obeys ({\it classically}) a differential equation, similar to the Liouville equation and reducing to it in the flat limit. A quadratic action formulation of this system is presented. The possibility and significance of quantizing the self-gravitating string, is discussed.
1991-10-06
2009-10-22
[ "hep-th" ]
Shahar Ben-Menahem (Stanford Linear Accelerator Center)
hep-th/9110015
The $W_3$-string spectrum
We study the spectrum of $W_3$ strings. In particular, we show that for appropriately chosen space-time signature, one of the scalar fields is singled out by the spin-3 constraint and is ``frozen'': no creation operators from it can appear in physical states and the corresponding momentum must assume a specific fixed value. The remaining theory is unitary and resembles an ordinary string theory in $d\ne26$ with anomalies cancelled by appropriate background charges. In the case of the $W_3$ string, however, the spin-two ``graviton'' is massive.
1991-10-05
2009-10-07
[ "hep-th" ]
C.N. Pope, L.J. Romans, E. Sezgin and K.S. Stelle
hep-th/9110013
Brst Cohomology and Physical States in 2D Supergravity Coupled to ${\hat c} \leq 1$ Matter
We study the BRST cohomology for two-dimensional supergravity coupled to $\hat c \leq 1$ superconformal matter in the conformal gauge. The super-Liouville and superconformal matters are represented by free scalar fields $\phi^L$ and $\phi^M$ and fermions $\psi^L$ and $\psi^M$, respectively, with suitable background charges, and these are coupled in such a way that the BRST charge is nilpotent. The physical states of the full theory are determined for NS and R sectors. It is shown that there are extra states with ghost number $N_{FP}=0,\pm 1$ for discrete momenta other than the degree of freedom corresponding to the ``center of mass", and that these are closely related to the ``null states" in the minimal models with $\hat c<1$.
1991-10-04
2009-10-22
[ "hep-th" ]
Katsumi Itoh and Nobuyoshi Ohta
hep-th/9110014
Mirror Manifolds: A Brief Review and Progress Report
We first give a complete, albeit brief, review of the discovery of mirror symmetry in $N=2$ string/conformal field theory. In particular, we describe the naturality arguments which led to the initial mirror symmetry conjectures and the subsequent work which established the existence of mirror symmetry through direct construction. We then review a number of striking consequences of mirror symmetry -- both conceptual and calculational. Finally, we describe recent work which introduces a variant on our original proof of the existence of mirror symmetry. This work affirms classical--quantum symmetry duality as well as extends the domain of our initial mirror symmetry construction.
1991-10-04
2007-05-23
[ "hep-th" ]
B.R. Greene and M.R. Plesser
hep-th/9110018
RG flows of non-diagonal minimal models perturbed by $\phi_{1,3}$
Studying perturbatively, for large m, the torus partition function of both (A,A) and (A,D) series of minimal models in the Cappelli, Itzykson, Zuber classification, deformed by the least relevant operator $\phi_{(1,3)}$, we disentangle the structure of $\phi_{1,3}$ flows. The results are conjectured on reasonable ground to be valid for all m. They show that (A,A) models always flow to (A,A) and (A,D) ones to (A,D). No hopping between the two series is possible. Also, we give arguments that there exist 3 isolated flows (E,A)-->(A,E) that, together with the two series, should exhaust all the possible $\phi_{1,3}$ flows. Conservation (and symmetry breaking) of non-local currents along the flows is discussed and put in relation to the A,D,E classification.
1991-10-04
2009-10-22
[ "hep-th" ]
F.Ravanini
hep-th/9110010
Quantum Solitons in Affine Toda Field Theories
The spectra of $A_r$ affine Toda field theories with imaginary coupling constant, are investigated. Soliton solutions are found, which, despite the non-unitary form of the Lagrangian, have real classical masses and are stable to small perturbations. The quantum corrections to the soliton masses are determined, to lowest order in $\hbar$. The solitons have the same spectrum as the fundamental Toda particles; a feature that is preserved in the quantum theory.
1991-10-03
2009-10-22
[ "hep-th" ]
Timothy Hollowood
hep-th/9110011
Quantum Gravity and String Theory, What Have We Learned?
This is a non-technical talk given at the Sixth Marcel Grossman Meeting on General Relativity, Kyoto, Japan in June 1991. Some developments in string theory over the last six years are discussed together with their qualitative implications for issues in quantum gravity.
1991-10-03
2007-05-23
[ "hep-th" ]
A. Strominger
hep-th/9110007
Some aspects of free field resolutions in 2D CFT with application to the quantum Drinfeld-Sokolov reduction
We review some aspects of the free field approach to two-dimensional conformal field theories. Specifically, we discuss the construction of free field resolutions for the integrable highest weight modules of untwisted affine Kac-Moody algebras, and extend the construction to a certain class of admissible highest weight modules. Using these, we construct resolutions of the completely degenerate highest weight modules of W-algebras by means of the quantum Drinfeld-Sokolov reduction. As a corollary we derive character formulae for these degenerate highest weight modules.
1991-10-02
2007-05-23
[ "hep-th" ]
P. Bouwknegt, J. McCarthy, and K. Pilch
hep-th/9110009
Constituent Quarks as Solitons
We exhibit soliton solutions of QCD in two dimensions that have the quantum numbers of quarks. They exist only for quarks heavier than the dimensional gauge coupling, and have infinite energy, corresponding to the presence of a string carrying the non-singlet color flux off to spatial infinity. The quark solitons also disappear at finite temperature, as the temperature-dependent effective quark mass is reduced in the approach to the quark/hadron phase transition.
1991-10-02
2009-09-11
[ "hep-th" ]
John Ellis, Yitzhak Frishman and Marek Karliner
hep-th/9110008
Duality Invariant Effective String Actions and Minimal Superstring Unification
Some results are presented concerning duality invariant effective string actions and the construction of automorphic functions for general (2,2) string compactifications. These considerations are applied in order to discuss the {\it minimal} unification of gauge coupling constants in orbifold compactifications with special emphasis on string threshold corrections.
1991-10-02
2008-11-26
[ "hep-th" ]
D. Luest
hep-th/9110005
Three-Dimensional Gravity and String Ghosts
It is known that much of the structure of string theory can be derived from three-dimensional topological field theory and gravity. We show here that, at least for simple topologies, the string diffeomorphism ghosts can also be explained in terms of three-dimensional physics.
1991-10-01
2010-04-28
[ "hep-th" ]
S. Carlip and I. I. Kogan
hep-th/9110002
The Effective String of 3D Gauge Systems at the Deconfining Transition
It is argued that the effective string of whatever 3D gauge system at the deconfining transition is universally described by the minimal $N=2$ extended superconformal theory at $c=1$. A universal value of the critical temperature is predicted.
1991-10-01
2009-10-22
[ "hep-th" ]
M. Caselle and F.Gliozzi
hep-th/9110012
From factorizable S-matrices to conformal invariance
Lecture notes on factorizable S-matrices, thermodynamic Bethe Ansatz and integrable perturbations of conformally invariant models; J.A.Swieca Summer School 1991
1991-10-01
2007-05-23
[ "hep-th" ]
Koberle Roland
hep-th/9110003
Field Identification in Non-Unitary Diagonal Cosets
We study the nonunitary diagonal cosets constructed from admissible representations of Kac-Moody algebras at fractional level, with an emphasis on the question of field identification. Generic classes of field identifications are obtained from the analysis of the modular S matrix. These include the usual class related to outer automorphisms, as well as some intrinsically nonunitary field identifications. They allow for a simple choice of coset field representatives where all field components of the coset are associated with integrable finite weights.
1991-10-01
2015-06-26
[ "hep-th" ]
Pierre Mathieu, David Senechal and Mark Walton
hep-th/9110006
On the Solution of Topological Landau-Ginzburg Models with $c=3$
The solution is given for the $c=3$ topological matter model whose underlying conformal theory has Landau-Ginzburg model $W=-\qa (x^4 +y^4)+\af x^2y^2$. While consistency conditions are used to solve it, this model is probably at the limit of such techniques. By using the flatness of the metric of the space of coupling constants I rederive the differential equation that relates the parameter \af\ to the flat coordinate $t$. This simpler method is also applied to the $x^3+y^6$-model.
1991-10-01
2009-10-22
[ "hep-th" ]
Z. Maassarani
hep-th/9110004
Manifestly $O(d,d)$ Invariant Approach to Space-Time Dependent String Vacua
An $O(d,d)$ symmetry of the manifold of string vacua that do not depend on $d$ (out of $D$) space-time coordinates has been recently identified. Here we write down, for $d=D-1$, the low energy equations of motion and their general solution in a manifestly $O(d,d)$-invariant form, pointing out an amusing similarity with the renormalization group framework. Previously considered cosmological and black hole solutions are recovered as particular examples.
1991-10-01
2015-06-26
[ "hep-th" ]
K.A. Meissner and G. Veneziano
hep-th/9110001
The Lie h-Invariant Conformal Field Theories and the Lie h-Invariant Graphs
We use the Virasoro master equation to study the space of Lie h-invariant conformal field theories, which includes the standard rational conformal field theories as a small subspace. In a detailed example, we apply the general theory to characterize and study the Lie h-invariant graphs, which classify the Lie h-invariant conformal field theories of the diagonal ansatz on SO(n). The Lie characterization of these graphs is another aspect of the recently observed Lie group-theoretic structure of graph theory.
1991-10-01
2015-06-26
[ "hep-th" ]
M.B. Halpern, E.B. Kiritsis, N.A. Obers
hep-th/9109058
Quantum Symmetries in 2D Massive Field Theories
We review various aspects of (infinite) quantum group symmetries in 2D massive quantum field theories. We discuss how these symmetries can be used to exactly solve the integrable models. A possible way for generalizing to three dimensions is shortly described.
1991-09-30
2007-05-23
[ "hep-th" ]
Denis Bernard
hep-th/9109057
On the possibility of $Z_N$ exotic supersymmetry in two dimensional Conformal Field Theory
We investigate the possibility to construct extended parafermionic conformal algebras whose generating current has spin $1+\frac{1}{K}$, generalizing the superconformal (spin 3/2) and the Fateev Zamolodchikov (spin 4/3) algebras. Models invariant under such algebras would possess $Z_K$ exotic supersymmetries satisfying (supercharge)$^K$ = (momentum). However, we show that for $K=4$ this new algebra allows only for models at $c=1$, for $K=5$ it is a trivial rephrasing of the ordinary $Z_5$ parafermionic model, for $K=6,7$ (and, requiring unitarity, for all larger $K$) such algebras do not exist. Implications of this result for existence of exotic supersymmetry in two dimensional field theory are discussed.
1991-09-30
2015-06-26
[ "hep-th" ]
F.Ravanini
hep-th/9109053
Gauge Coupling Running in Minimal SU(3)xSU(2)xU(1) Superstring Unification
We study the evolution of the gauge coupling constants in string unification schemes in which the light spectrum below the compactification scale is exactly that of the minimal supersymmetric standard model. In the absence of string threshold corrections the predicted values $\sin^2\theta _W=0.218$ and $\alpha _s=0.20$ are in gross conflict with experiment, but these corrections are generically important. One can express the string threshold corrections to $\sin^2\theta _W$ and $\alpha_s$ in terms of certain $modular$ $weights$ of quark, lepton and Higgs superfields as well as the $moduli$ of the string model. We find that in order to get agreement with the experimental measurements within the context of this $minimal$ scheme, certain constraints on the $modular$ $weights$ of the quark, lepton and Higgs superfields should be obeyed. Our analysis indicates that this $minimal$ $string$ $unification$
1991-09-27
2009-10-07
[ "hep-th" ]
Luis Ibanez, Dieter Luest and Graham Ross
hep-th/9109054
Integrable Discrete Linear Systems and One-Matrix Model
In this paper we analyze one-matrix models by means of the associated discrete linear systems. We see that the consistency conditions of the discrete linear system lead to the Virasoro constraints. The linear system is endowed with gauge invariances. We show that invariance under time-independent gauge transformations entails the integrability of the model, while the double scaling limit is connected with a time-dependent gauge transformation. We derive the continuum version of the discrete linear system, we prove that the partition function is actually the $\tau$-function of the KdV hierarchy and that the linear system completely determines the Virasoro constraints.
1991-09-27
2014-11-18
[ "hep-th" ]
L. Bonora, M. Martellini and C. S. Xiong
hep-th/9109055
Deformations, Symmetries and Topological Degrees of Freedom of the String
We discuss three closely related questions; i)~Given a conformal field theory, how may we deform it? ii)~What are the symmetries of string theory? and iii)~Does string theory have free parameters? We show that there is a distinct deformation of the stress tensor for every solution to the linearised covariant equations of motion for the massless modes of the Bosonic string, and use this result to discuss the symmetries of the string. We also find an additional finite dimensional space of deformations which may correspond to free parameters of string theory, or alternatively may be interpreted as topological degrees of freedom, perhaps analogous to the isolated states found in two dimensions.
1991-09-27
2009-10-02
[ "hep-th" ]
Mark Evans and Ioannis Giannakis (Rockefeller University)
hep-th/9109056
A representation of the exchange relation for affine Toda field theory
Vertex operators are constructed providing representations of the exchange relations containing either the S-matrix of a real coupling (simply-laced) affine Toda field theory, or its minimal counterpart. One feature of the construction is that the bootstrap relations for the S-matrices follow automatically from those for the conserved quantities, via an algebraic interpretation of the fusing of two particles to form a single bound state.
1991-09-27
2009-10-22
[ "hep-th" ]
E. Corrigan and P.E. Dorey
hep-th/9109052
Instantons and Solitons in Heterotic String Theory
This is a transcript of lectures given at the Sixth Jorge Andre Swieca Summer School in Theoretical Physics. The subject of these lectures is soliton solutions of string theory. We construct a class of exact conformal field theories possessing a spacetime soliton or instanton interpretation and present a preliminary discussion of their physical properties.
1991-09-26
2012-08-27
[ "hep-th" ]
Curtis G. Callan, Jr
hep-th/9109051
The Damping of Energetic Gluons and Quarks in High-Temperature QCD
When a gluon or a quark is sent through the hot QCD plasma it can be absorbed into the ambient heat bath and so can acquire an effective lifetime. At high temperatures and for weak couplings the inverse lifetime, or damping rate, for energetic quarks and transverse gluons, (those whose momenta satisfy $|\p| \gg gT$) is given by $\gamma(\p) = c\; g^2 \log\left({1\over g}\right)\; T + O(g^2T)$. We show that very simple arguments suffice both to fix the numerical coefficient, $c$, in this expression and to show that the $O(g^2T)$ contribution is incalculable in perturbation theory without further assumptions. For QCD with $N_c$ colours we find (expressed in terms of the casimir invariants $C_a=N_c$ and $C_f=(N_c^2-1)/(2N_c)$): $c_g=+{C_a\over 4\pi}$ for gluons and $c_q=+{C_f\over 4\pi}$ for quarks. These numbers agree with the more detailed calculations of Pisarski \etal\ but disagree with those of Lebedev and Smilga. The simplicity of the calculation also permits a direct verification of the gauge-invariance and physical sign of the result.
1991-09-26
2009-12-30
[ "hep-th" ]
C.P. Burgess and A.L. Marini
hep-th/9109050
Structure constants in the N=1 superoperator algebra
Using the Coulomb Gas formulation of N=1 Superconformal Field Theories, we extend the arguments of Dotsenko and Fateev for the bosonic case to evaluate the structure constants of N=1 minimal Superconformal Algebras in the Neveu-Schwarz sector.
1991-09-25
2015-06-26
[ "hep-th" ]
L. Alvarez-Gaume, Ph. Zaugg
hep-th/9109047
The supersymmetric sigma model and the geometry of the Weyl-Kac character formula
Field theoretic and geometric ideas are used to construct a chiral supersymmetric field theory whose ground state is a specified irreducible representation of a centrally extended loop group. The character index of the associated supercharge (an appropriate Dirac operator on $LG/T$) is the Weyl-K\v{a}c character formula which we compute explicitly by the steepest descent approximation.
1991-09-25
2009-10-22
[ "hep-th" ]
Orlando Alvarez, I.M. Singer and Paul Windey
hep-th/9109048
Elements of String Cosmology
Aspects of string cosmology for critical and non-critical strings are discussed emphasizing the necessity to account for the dilaton dynamics for a proper incorporation of ``large - small" duality. This drastically modifies the intuition one has with Einstein's gravity. For example winding modes, even though contribute to energy density, oppose expansion and if not annihilated will stop the expansion. Moreover we find that the radiation dominated era of the standard cosmology emerges quite naturally in string cosmology. Our analysis of non-critical string cosmology provides a reinterpretation of the (universal cover of the) recently studied two dimensional black hole solution as a conformal realization of cosmological solutions found previously by Mueller.
1991-09-25
2009-09-17
[ "hep-th" ]
A. A. Tseytlin and C. Vafa
hep-th/9109049
Extended Inflation from Strings
We study the possibility of extended inflation in the effective theory of gravity from strings compactified to four dimensions and find that it strongly depends on the mechanism of supersymmetry breaking. We consider a general class of string--inspired models which are good candidates for successful extended inflation. In particular, the $\omega$--problem of ordinary extended inflation is automatically solved by the production of only very small bubbles until the end of inflation. We find that the inflaton field could belong either to the untwisted or to the twisted massless sectors of the string spectrum, depending on the supersymmetry breaking superpotential.
1991-09-25
2009-10-22
[ "hep-th" ]
J. Garcia-Bellido and M. quiros
hep-th/9109046
Hermitian vs. Anti-Hermitian 1-Matrix Models and Their Hierarchies
Building on a recent work of \v C. Crnkovi\'c, M. Douglas and G. Moore, a study of multi-critical multi-cut one-matrix models and their associated $sl(2,C)$ integrable hierarchies, is further pursued. The double scaling limits of hermitian matrix models with different scaling ans\"atze, lead, to the KdV hierarchy, to the modified KdV hierarchy and part of the non-linear Schr\"odinger hierarchy. Instead, the anti-hermitian matrix model, in the two-arc sector, results in the Zakharov-Shabat hierarchy, which contains both KdV and mKdV as reductions. For all the hierarchies, it is found that the Virasoro constraints act on the associated tau-functions. Whereas it is known that the ZS and KdV models lead to the Virasoro constraints of an $sl(2,C)$ vacuum, we find that the mKdV model leads to the Virasoro constraints of a highest weight state with arbitrary conformal dimension.
1991-09-24
2011-07-19
[ "hep-th" ]
Timothy Hollowood, Luis Miramontes, Andrea Pasquinucci and Chiara Nappi
hep-th/9109041
Renormalization Group Patterns and C-Theorem in More Than Two Dimensions
We elaborate on a previous attempt to prove the irreversibility of the renormalization group flow above two dimensions. This involves the construction of a monotonically decreasing $c$-function using a spectral representation. The missing step of the proof is a good definition of this function at the fixed points. We argue that for all kinds of perturbative flows the $c$-function is well-defined and the $c$-theorem holds in any dimension. We provide examples in multicritical and multicomponent scalar theories for dimension $2<d<4$. We also discuss the non-perturbative flows in the yet unsettled case of the $O(N)$ sigma-model for $2\leq d\leq 4$ and large $N$.
1991-09-24
2009-10-22
[ "hep-th" ]
Andrea Cappelli, Jos\'e Ignacio Latorre and Xavier Vilasis-Cardona
hep-th/9109043
Implications of Target Space Duality
Based on the assumption that the target space duality ($T\to 1/T$) is preserved even nonperturbatively, the properties of static string vacua are studied. A discussion of the effective four-dimensional supergravity action based on target-space modular symmetry $SL(2,{\bf Z})$ is presented. The nonperturbative superpotential removes the vacuum degeneracy with respect to the compactification modulus ($T$) generically breaks supersymmetry with negative cosmological constant. Charged matter fields get negative $(mass)^2$ signalling an additional instability of string vacuum and the blowing up of orbifold singularities. In addition for a class of modularly invariant potentials topologically stable stringy domain walls of nontrivial compaction modulus field configuration are found. They are supersymmetric solutions, thus saturating the Bogomolnyi bound. Their physical implications are discussed.
1991-09-24
2008-02-03
[ "hep-th" ]
M. Cvetic
hep-th/9109044
Topological Defects in the Moduli Sector of String Theory
We point out that the moduli sector of the $(2,2)$ string compactification with its nonperturbatively preserved non-compact symmetries is a fertile framework to study global topological defects, thus providing a natural source for the large scale structure formation. Based on the target space modular invariance of the nonperturbative superpotential of the four-dimensional N=1 supersymmetric string vacua, topologically stable stringy domain walls are found. They are supersymmetric solutions, thus saturating the Bogomolnyi bound. It is also shown that there are moduli sectors that allow for the global monopole-type and texture-type configurations whose radial stability is ensured by higher derivative terms.
1991-09-24
2008-02-03
[ "hep-th" ]
M. Cvetic
hep-th/9109042
Singular Vectors and Conservation Laws of Quantum KdV type equations
We give a direct proof of the relation between vacuum singular vectors and conservation laws for the quantum KdV equation or equivalently for $\Phi_{(1,3)}$-perturbed conformal field theories. For each degree at which a classical conservation law exists, we find a quantum conserved quantity for a specific value of the central charge. Various generalizations ($N=1,2$ supersymmetric, Boussinesq) of this result are presented.
1991-09-24
2009-10-22
[ "hep-th" ]
P. Di Francesco and P. Mathieu
hep-th/9109045
Note on Discrete Gauge Anomalies
We consider the probem of gauging discrete symmetries. All valid constraints on such symmetries can be understood in the low energy theory in terms of instantons. We note that string perturbation theory often exhibits global discrete symmetries, which are broken non-perturbatively.
1991-09-24
2011-09-29
[ "hep-th" ]
T. Banks and M. Dine
hep-th/9109040
Irrational Axions as a Solution of The Strong CP Problem in an Eternal Universe
We exhibit a novel solution of the strong CP problem, which does not involve any massless particles. The low energy effective Lagrangian of our model involves a discrete spacetime independent axion field which can be thought of as a parameter labeling a dense set of $\theta$ vacua. In the full theory this parameter is seen to be dynamical, and the model seeks the state of lowest energy, which has $\theta_{eff} = 0$. The processes which mediate transitions between $\theta$ vacua involve heavy degrees of freedom and are very slow. Consequently, we do not know whether our model can solve the strong CP problem in a universe which has been cool for only a finite time. We present several speculations about the cosmological evolution of our model.
1991-09-23
2009-09-15
[ "hep-th" ]
Tom Banks, Michael Dine and Nathan Seiberg
hep-th/9109034
A Deformation Theory of Self-Dual Einstein Spaces
The self-dual Einstein equations on a compact Riemannian 4-manifold can be expressed as a quadratic condition on the curvature of an $SU(2)$ (spin) connection which is a covariant generalization of the self-dual Yang-Mills equations. Local properties of the moduli space of self-dual Einstein connections are described in the context of an elliptic complex which arises in the linearization of the quadratic equations on the $SU(2)$ curvature. In particular, it is shown that the moduli space is discrete when the cosmological constant is positive; when the cosmological constant is negative the moduli space can be a manifold the dimension of which is controlled by the Atiyah-Singer index theorem.
1991-09-20
2007-05-23
[ "hep-th" ]
C. G. Torre
hep-th/9109037
Some Correlation Functions of Minimal Superconformal Models Coupled to Supergravity
We compute general three-point functions of minimal superconformal models coupled to supergravity in the Neveu-Schwarz sector for spherical topology thus extending to the superconformal case the results of Goulian and Li and of Dotsenko.
1991-09-20
2009-10-22
[ "hep-th" ]
L. ALvarez-Gaume Ph. Zaugg
hep-th/9109038
Twisting Classical Solutions in Heterotic String Theory
We show that, given a classical solution of the heterotic string theory which is independent of $d$ of the space time directions, and for which the gauge field configuration lies in a subgroup that commutes with $p$ of the $U(1)$ generators of the gauge group, there is an $O(d)\otimes O(d+p)$ transformation, which, acting on the solution, generates new classical solutions of the theory. With the help of these transformations we construct black 6-brane solutions in ten dimensional heterotic string theory carrying independent magnetic, electric and antisymmetric tensor gauge field charge, by starting from a black 6-brane solution that carries magnetic charge but no electric or antisymmetric tensor gauge field charge. The electric and the magnetic charges point in different directions in the gauge group.
1991-09-20
2009-09-15
[ "hep-th" ]
S. F. Hassan and Ashoke Sen
hep-th/9109035
Classification of Simple Current Invariants
We summarize recent work on the classification of modular invariant partition functions that can be obtained with simple currents in theories with a center (Z_p)^k with p prime. New empirical results for other centers are also presented. Our observation that the total number of invariants is monodromy-independent for (Z_p)^k appears to be true in general as well. (Talk presented in the parallel session on string theory of the Lepton-Photon/EPS Conference, Geneva, 1991.)
1991-09-20
2008-11-26
[ "hep-th" ]
B. Gato-Rivera and A.N. Schellekens
hep-th/9109036
Batalin-Vilkovisky Lagrangian Quantisation
The Lagrangian Batalin-Vilkovisky (BV) formalism gives the rules for the quantisation of a general class of gauge theories which contain all the theories known up to now. It does, however, not only give a recipe to obtain a gauge fixed action, but also gives a nice understanding of the mechanism behind gauge fixing. It moreover brings together a lot of previous knowledge and recipes in one main concept~: the canonical transformations. We explain the essentials of this formalism and give related results on the superparticle. Also anomalies (in general functions of fields and antifields) can be obtained in this formalism, and it gives the relation between anomalies in different gauges. A Pauli-Villars scheme can be used to obtain a regularised definition of the expressions at the one loop level. The calculations become similar to those of Fujikawa with the extra freedom of using arbitrary variables. A discrepancy between anomalies in light-cone gauge of the Green-Schwarz superstring and in the semi-light-cone gauge is discussed.
1991-09-20
2007-05-23
[ "hep-th" ]
Antoine Van Proeyen
hep-th/9109039
A $\kappa$-Symmetry Calculus for Superparticles
We develop a $\kappa$-symmetry calculus for the d=2 and d=3, N=2 massive superparticles, which enables us to construct higher order $\kappa$-invariant actions. The method relies on a reformulation of these models as supersymmetric sigma models that are invariant under local worldline superconformal transformations. We show that the $\kappa$-symmetry is embedded in the superconformal symmetry so that a calculus for the $\kappa$-symmetry is equivalent to a tensor calculus for the latter. We develop such a calculus without the introduction of a worldline supergravity multiplet.
1991-09-20
2009-10-22
[ "hep-th" ]
Jerome P. Gauntlett
hep-th/9112059
Strings with Discrete Target Space
We investigate the field theory of strings having as a target space an arbitrary discrete one-dimensional manifold. The existence of the continuum limit is guaranteed if the target space is a Dynkin diagram of a simply laced Lie algebra or its affine extension. In this case the theory can be mapped onto the theory of strings embedded in the infinite discrete line $\Z$ which is the target space of the SOS model. On the regular lattice this mapping is known as Coulomb gas picture. ... Once the classical background is known, the amplitudes involving propagation of strings can be evaluated by perturbative expansion around the saddle point of the functional integral. For example, the partition function of the noninteracting closed string (toroidal world sheet) is the contribution of the gaussian fluctuations of the string field. The vertices in the corresponding Feynman diagram technique are constructed as the loop amplitudes in a random matrix model with suitably chosen potential.
1991-09-19
2009-10-22
[ "hep-th" ]
I. Kostov
hep-th/9109033
SU(3) x SU(2) x U(1): The residual symmetry of extended conformal gravity
Within the 4-dimensional conformal algebra, the presence of two translation operators implies the existence of 3 distinct metrics of definite Weyl weight constructible from the translational gauge fields. If we demand that each of these metrics give rise to a gauge theory of gravity, we are led to extend the symmetry so that each of these three metrics has a corresponding translation operator. Assigning a vierbein to each of these three translations, a different spacetime metric arises for every choice of inner product of the vierbeins. The covering group of the compact part of the minimal transitive group classifying these inner products is $SU(4)$. An additional $SU(2)$ symmetry classifies the antisymmetric parts of the vierbein product. If the metric is chosen as the gauge field of the translations in the standard way, the SU(4) part of this symmetry is broken to the semidirect product of $SU(3)$ with $U(1)$.
1991-09-19
2008-02-06
[ "hep-th" ]
James T. Wheeler
hep-th/9109032
Interaction of Discrete States in Two-Dimensional String Theory
We study the couplings of discrete states that appear in the string theory embedded in two dimensions, and show that they are given by the structure constants of the group of area preserving diffeomorphisms. We propose an effective action for these states, which is itself invariant under this infinite-dimensional group.
1991-09-19
2015-06-26
[ "hep-th" ]
I. R. Klebanov and A. M. Polyakov
hep-th/9109028
New Special Operators in $W$-Gravity Theories
We find new special physical operators of $W_3 -$gravity having non trivial ghost sectors. Some of these operators may be viewed as the liouville dressings of the energy operator of the Ising model coupled to {\it 2d~gravity} and this fills in a gap in the connection between pure $W_3 -$gravity and Ising model coupled to 2d gravity found in our previous work. We formulate a selection rule required for the calculation of correlators in $W -$gravity theories. Using this rule, we construct the non ghost part of the new operators of $W_N -$gravity and find that they represent the $(N , N+1)$ minimal model operators from both inside and outside the minimal table. Along the way we obtain the canonical spectrum of $W_N -$gravity for all $N$ .
1991-09-18
2007-05-23
[ "hep-th" ]
S. Kalyana Rama
hep-th/9109030
Topology Change in General Relativity
A review is given of recent work on topology changing solutions to the first order form of general relativity. These solutions have metrics which are smooth everywhere, invertible almost everywhere, and have bounded curvature. The importance of considering degenerate metrics is discussed, and the possibility that quantum effects can suppress topology change is briefly examined.
1991-09-18
2007-05-23
[ "hep-th" ]
Gary T. Horowitz
hep-th/9109029
Beyond the Large N Limit: Non-linear W(infinity) as symmetry of the SL(2,R)/U(1) coset model
We show that the symmetry algebra of the $SL(2,R)_{k}/U(1)$ coset model is a non-linear deformation of $W_{\infty}$, characterized by $k$. This is a universal $W$-algebra which linearizes in the large $k$ limit and truncates to $W_{N}$ for $k=-N$. Using the theory of non-compact parafermions we construct a free field realization of the non-linear $W_{\infty}$ in terms of two bosons with background charge. The $W$-characters of all unitary $SL(2,R)/U(1)$ representations are computed. Applications to the physics of 2-d black hole backgrounds are also discussed and connections with the KP approach to $c=1$ string theory are outlined.
1991-09-18
2015-06-26
[ "hep-th" ]
I. Bakas, E. Kiritsis
hep-th/9109027
On the connection between Quantum Mechanics and the geometry of two-dimensional strings
On the basis of an area-preserving symmetry in the phase space of a one-dimensional matrix model - believed to describe two-dimensional string theory in a black-hole background which also allows for space-time foam - we give a geometric interpretation of the fact that two-dimensional stringy black holes are consistent with conventional quantum mechanics due to the infinite gauged `W-hair' property that characterises them.
1991-09-17
2009-09-11
[ "hep-th" ]
J.Ellis, N.E. Mavromatos, D.V. Nanopoulos
hep-th/9109031
Constant Curvature and Non-Perturbative W3 Gravity
We show that the new classical action for two dimensional gravity (the Jackiw-Teitelboim model) possesses a $W_3$ algebra. We quantise the resulting $W_3$ gravity in the presence of matter fields with arbitrary central charges and obtain the critical exponents. The auxiliary field of the model, expressing the constancy of the scalar curvature, can be interpreted as one of the physical degrees of freedom of the $W_3$ gravity. Our expressions are corrections to some previously published results for this model where the $W_3$ symmetry was not accounted for.
1991-09-17
2007-05-23
[ "hep-th" ]
N. Mohammedi
hep-th/9109026
String Effective Action and Two Dimensional Charged Black Hole
Graviton-dilaton background field equations in three space-time dimensions, following from the string effective action are solved when the metric has only time dependence. By taking one of the two space dimensions as compact, our solution reproduces a recently discovered charged black hole solution in two space-time dimensions. Solutions in presence of nonvanishing three dimensional background antisymmetric tensor field are also discussed.
1991-09-14
2015-06-26
[ "hep-th" ]
S. Pratik Khastgir and Alok Kumar
hep-th/9109024
On the Liouville Approach to Correlation Functions for 2-D Quantum Gravity
We evaluate the three point function for arbitrary states in bosonic minimal models on the sphere coupled to quantum gravity in two dimensions. The validity of the formal continuation in the number of Liouville screening charge insertions is shown directly from the Liouville functional integral using semi-classical methods.
1991-09-13
2009-10-22
[ "hep-th" ]
Kenichiro Aoki and Eric D'Hoker
hep-th/9109025
Correlation functions of minimal models coupled to two dimensional quantum supergravity
We compute the three point functions of Neveu--Schwarz primary fields of the minimal models on the sphere when coupled to supergravity in two dimensions. The results show that the three point correlation functions are determined by the scaling dimensions of the fields, as in the bosonic case.
1991-09-13
2009-10-22
[ "hep-th" ]
Kenichiro Aoki and Eric D'Hoker
hep-th/9109022
Some Applications of String Field Theory
We study general properties of the classical solutions in non-polynomial closed string field theory and their relationship with two dimensional conformal field theories. In particular we discuss how different conformal field theories which are related by marginal or nearly marginal deformations can be regarded as different classical solutions of some underlying string field theory. We also discuss construction of a classical solution labelled by infinite number of parameters in string field theory in two dimensions. For a specific set of values of the parameters the solution can be identified to the black hole solution.
1991-09-12
2007-05-23
[ "hep-th" ]
Ashoke Sen
hep-th/9109023
On quantum group symmetries of conformal field theories
The appearance of quantum groups in conformal field theories is traced back to the Poisson-Lie symmetries of the classical chiral theory. A geometric quantization of the classical theory deforms the Poisson-Lie symmetries to the quantum group ones. This elucidates the fundamental role of chiral symmetries that quantum groups play in conformal models. As a byproduct, one obtains a more geometric approach to the representation theory of quantum groups.
1991-09-12
2007-05-23
[ "hep-th" ]
Fernando Falceto and Krzysztof Gawedzki
hep-th/9109019
Restricted Quantum Affine Symmetry of Perturbed Minimal Models
We study the structure of superselection sectors of an arbitrary perturbation of a conformal field theory. We describe how a restriction of the q-deformed $\hat{sl(2)}$ affine Lie algebra symmetry of the sine-Gordon theory can be used to derive the S-matrices of the $\Phi^{(1,3)}$ perturbations of the minimal unitary series. This analysis provides an identification of fields which create the massive kink spectrum. We investigate the ultraviolet limit of the restricted sine-Gordon model, and explain the relation between the restriction and the Fock space cohomology of minimal models. We also comment on the structure of degenerate vacuum states. Deformed Serre relations are proven for arbitrary affine Toda theories, and it is shown in certain cases how relations of the Serre type become fractional spin supersymmetry relations upon restriction.
1991-09-11
2015-06-26
[ "hep-th" ]
G. Felder and A. LeClair
hep-th/9109020
Infinite Quantum Group Symmetry in 2d Quantum Field Theory
I describe how integrable quantum field theories in 2 spacetime dimensions are characterized by infinite dimensional quantum group symmetries, namely the q-deformations of affine Lie algebras, and their Yangian limit. These symmetries can provide a new non-perturbative formulation of the theories.
1991-09-11
2007-05-23
[ "hep-th" ]
Andre LeClair
hep-th/9109016
Classical Gravity Coupled to Liouville Theory
We consider the two dimensional Jackiw-Teitelboim model of gravity. We first couple the model to the Liouville action and $c$ scalar fields and show, treating the combined system as a non linear sigma model, that the resulting theory can be interpreted as a critical string moving in a target space of dimension $D=c+2$. We then analyse perturbatively a generalised model containing a kinetic term and an arbitrary potential for the auxiliary field. We use the background field method and work with covariant gauges. We show that the renormalisability of the theory depends on the form of the potential. For a general potential, the theory can be renormalised as a non linear sigma model. In the particular case of a Liouville-like potential, the theory is renormalisable in the usual sense.
1991-09-11
2009-10-22
[ "hep-th" ]
F.D. Mazzitelli and N. Mohammedi
hep-th/9109018
Stochastic Quantization vs. KdV Flows in 2D Quantum Gravity
We consider the stochastic quantization scheme for a non-perturbative stabilization of 2D quantum gravity and prove that it does not satisfy the KdV flow equations. It therefore differs from a recently suggested matrix model which allows real solutions to the KdV equations. The behaviour of the Fermi energy, the free energy and macroscopic loops in the stochastic quantization scheme are elucidated.
1991-09-11
2009-10-22
[ "hep-th" ]
J. Ambjorn, C.V. Johnson and T.R.Morris
hep-th/9109017
Singular vectors by Fusions in affine su(2)
Explicit expressions for the singular vectors in the highest weight representations of $A_1^{(1)}$ are obtained using the fusion formalism of conformal field theory.
1991-09-11
2009-10-22
[ "hep-th" ]
M. Bauer and N. Sochen
hep-th/9109021
Excited-state thermodynamics
In the last several years, the Casimir energy for a variety of 1+1-dimensional integrable models has been determined from the exact S-matrix. It is shown here how to modify the boundary conditions to project out the lowest-energy state, which enables one to find excited-state energies. This is done by calculating thermodynamic expectation values of operators which generate discrete symmetries. This is demonstrated with a number of perturbed conformal field theories, including the Ising model, the three-state Potts model, ${\bf Z}_n$ parafermions, Toda minimal S-matrices, and massless Goldstinos.
1991-09-11
2009-10-22
[ "hep-th" ]
Paul Fendley
hep-th/9109013
Collective Field Representation of Nonrelativistic Fermions in (1+1) Dimensions
A collective field formalism for nonrelativistic fermions in (1+1) dimensions is presented. Applications to the D=1 hermitian matrix model and the system of one-dimensional fermions in the presence of a weak electromagnetic field are discussed.
1991-09-10
2007-05-23
[ "hep-th" ]
Dimitra Karabali
hep-th/9109011
Critical Boundary Conditions for the Effective String
Gauge systems in the confining phase induce constraints at the boundaries of the effective string, which rule out the ordinary bosonic string even with short distance modifications. Allowing topological excitations, corresponding to winding around the colour flux tube, produces at the quantum level a universal free fermion string with a boundary phase nu=1/4. This coincides with a model proposed some time ago in order to fit Monte Carlo data of 3D and 4D Lattice gauge systems better. A universal value of the thickness of the colour flux tube is predicted.
1991-09-10
2019-08-17
[ "hep-th" ]
M.Caselle, R.Fiore, F.Gliozzi, P.Provero and S.Vinti
hep-th/9109012
Is S=1 for c=1?
The $c=1$ string in the Liouville field theory approach is shown to possess a nontrivial tree-level $S$-matrix which satisfies factorization property implied by unitary, if all the extra massive physical states are included.
1991-09-10
2009-10-22
[ "hep-th" ]
D. Minic and Z. Yang