Master Ward Identity for Nonlocal Symmetries in D=2 Principal Chiral Models

We derive, in path integral approach, the (anomalous) master Ward identity associated with an infinite set of nonlocal conservation laws in two-dimensional principal chiral modelsComment: 12 pages, harvmac, minors correction

Currents, Charges, and Canonical Structure of Pseudodual Chiral Models

We discuss the pseudodual chiral model to illustrate a class of two-dimensional theories which have an infinite number of conservation laws but allow particle production, at variance with naive expectations. We describe the symmetries of the pseudodual model, both local and nonlocal, as transmutations of the symmetries of the usual chiral model. We refine the conventional algorithm to more efficiently produce the nonlocal symmetries of the model, and we discuss the complete local current algebra for the pseudodual theory. We also exhibit the canonical transformation which connects the usual chiral model to its fully equivalent dual, further distinguishing the pseudodual theory.Comment: 15 pages, ANL-HEP-PR-93-85,Miami-TH-1-93,Revtex (references updated, format improved to Revtex

Monopoles and Instantons in String Theory

In recent work, several classes of solitonic solutions of string theory with higher-membrane structure have been obtained. These solutions can be classified according to the symmetry possessed by the solitons in the subspace of the spacetime transverse to the membrane. Solitons with four-dimensional spherical symmetry represent instanton solutions in string theory, while those with three-dimensional spherical symmetry represent magnetic monopole-type solutions. For both of these classes, we discuss bosonic as well as heterotic solutions.Comment: 16 page

Gauged WZW models and Non-abelian duality

We consider WZW models based on the non-semi-simple algebras that they were recently constructed as contractions of corresponding algebras for semi-simple groups. We give the explicit expression for the action of these models, as well as for a generalization of them, and discuss their general properties. Furthermore we consider gauged WZW models based on these non-semi-simple algebras and we show that there are equivalent to non-abelian duality transformations on WZW actions. We also show that a general non-abelian duality transformation can be thought of as a limiting case of the non-abelian quotient theory of the direct product of the original action and the WZW action for the symmetry gauge group $H$. In this action there is no Lagrange multiplier term that constrains the gauge field strength to vanish. A particular result is that the gauged WZW action for the coset $(G_k \otimes H_l)/H_{k+l}$ is equivalent, in the limit $l\to \infty$, to the dualized WZW action for $G_k$ with respect to the subgroup $H$.Comment: 35 pages, harvmac, THU-94/01 (a few minor changes in subsec. 4.1 are made, a 3rd App. and a Note are added

Sigma model approach to string theory effective actions with tachyons

Motivated by recent discussions of actions for tachyon and vector fields related to tachyon condensation in open string theory we review and clarify some aspects of their derivation within sigma model approach. In particular, we demonstrate that the renormalized partition function $Z(T,A)$ of boundary sigma model gives the effective action for massless vectors which is consistent with string S-matrix and beta function, resolving an old problem with this suggestion in bosonic string case at the level of the leading $F^2 (dF)^2$ derivative corrections to Born-Infeld action. We give manifestly gauge invariant definition of $Z(T,A)$ in non-abelian NSR open string theory and check that its derivative reproduces the tachyon beta function in a particular scheme. We also discuss derivation of similar actions for tachyon and massless modes in closed bosonic and NSR (type 0) string theories.Comment: 26 pages, harvmac. To appear in the special issue of J. Math. Phys. on Strings, Branes and M-theory. v4: minor editorial changes, version to appear in JM

Strings in Plane Wave Backgrounds Revisited

String theory in an exact plane wave background is explored. A new example of singularity in the sense of string theory for nonsingular spacetime metric is presented. The 4-tachyon scattering amplitude is constructed. The spectrum of states found from the poles in the factorization turns out to be equivalent to that of the theory in flat space-time. The massless vertex operator is obtained from the residue of the first order pole.Comment: 15 pages, GTCRG-8, RevTe

Non-Abelian T-duality and consistent truncations in type-II supergravity

For a general class of SO(4) symmetric backgrounds in type II-supergravity, we show that the action of non-Abelian T-duality can be described via consistent truncation to seven dimensional theories with seemingly massive modes. As such, any solution to these theories uplifts to both massive type IIA and IIB supergravities presenting an invertible map between the two. For supersymmetric backgrounds, we show that for spinors transforming under SO(4) the non-Abelian T-duality transformation breaks the original supersymmetry by half. We use these mappings to generate the non-Abelian T-duals of the maximally supersymmetric pp-wave, the Lin, Lunin, Maldacena geometries and spacetimes with Lifshitz symmetry.Comment: 41 pages, references added, published versio

Type IIB supergravity solutions with AdS5 from Abelian and non-Abelian T dualities

We present a large class of new backgrounds that are solutions of type IIB supergravity with a warped AdS${}_5$ factor, non-trivial axion-dilaton, $B$-field and three-form Ramond-Ramond flux but yet have no five-form flux. We obtain these solutions and many of their variations by judiciously applying non-Abelian and Abelian T-dualities, as well as coordinate shifts to AdS${}_5\times X_5$ IIB supergravity solutions with $X_5=S^5, T^{1,1}, Y^{p,q}$. We address a number of issues pertaining to charge quantization in the context of non-Abelian T-duality. We comment on some properties of the expected dual super conformal field theories by studying their CFT central charge holographically. We also use the structure of the supergravity Page charges, central charges and some probe branes to infer aspects of the dual super conformal field theories.Comment: 71 pages, one table. v2: References added, some normalizations corrected, results unchange

Time-Dependent Backgrounds in 2D String Theory and the SS-matrix Generating Functional

We study the time-dependent tachyon backgrounds of the string collective field theory using the formalism of the $S$-matrix generating functional. In the process we clarify the connection between two ways of calculating the $S$-matrix, the one using the Feynman rule and the other using the classical solution to the nonlinear equation of motion. We develop the formalism for general backgrounds and apply it to the gravitational sine-Gordon model in detail. We reproduce the conformal field theory calculation which was based on expanding around the static $c=1$ theory. Furthermore, we prove that the tree- level partition function of this model shows the scaling behavior corresponding to $c=0$ model in the limit $p \to 0$ of sine-Gordon `momentum' $p$.Comment: 23 pages, BROWN-HET-92