Galilean anti-de-Sitter spacetime in Romans theory

The Romans type IIA theory is the only known example of 10-dimensional maximal supergravity where (tensor) fields are explicitly massive. We provide an example of a non-relativistic anti-de Sitter $NRadS_4\times S^6$ background as a solution in massive type IIA. A compactification of which on $S^6$ gives immediately the prototype NRadS background in D=4 which is proposed to be dual to `cold atoms' or unitary fermions on a wire.Comment: 10 pages; change in reference

STRING STRING DUALITY CONJECTURE IN SIX DIMENSIONS AND CHARGED SOLITONIC STRINGS

It has recently been conjectured that the type IIA string theory compactified on K3 and the heterotic string theory compactified on a four dimensional torus describe identical string theories. The fundamental heterotic string can be regarded as a non-singular soliton solution of the type IIA string theory with a semi-infinite throat. We show that this solution admits 24 parameter non-singular deformation describing a fundamental heterotic string carrying electric charge and current. The charge is generated due to the coupling of the gauge fields to the anti-symmetric tensor field, and not to an explicit source term. This clarifies how soliton solutions carrying charge under the Ramond-Ramond fields can be constructed in the type IIA theory, and provides further support to the string string duality conjecture. Similarly, the fundamental type IIA string can be regarded as a non-singular solution of the heterotic string theory with a semi-infinite throat, but this solution does not admit any deformation representing charged string. This is also consistent with the expectation that a fundamental type IIA string does not carry any charge that couples to the fields originating in the Ramond-Ramond sector.Comment: 17 pages, LaTeX fil

Galilean type IIA backgrounds and a map

We obtain non-relativistic AdS4 X CP3 solutions with dynamical exponent 3 in type IIA string theory, both with and without Romans mass. The compactifications to four dimensions are found to describe Proca fields in anti-de Sitter spacetime. This leads us to conclude that the massive and massless IIA theories should be identified in four dimensions and the Romans mass should be identified with the `flux' along CP3 in a definite manner. From supergravity point of view, it is suggestive of some four-dimensional symmetry that rotates Romans mass into the flux along CP3. We also provide M-theory Galilean ABJM background which gives rise to the nonrelativistic type IIA solution.Comment: 10 pages;v2: major revisions, errors on supersymmetry corrected and references added; to be published in MPL

Meta-Stable Brane Configurations with Seven NS5-Branes

We present the intersecting brane configurations consisting of NS-branes, D4-branes(and anti D4-branes) and O6-plane, of type IIA string theory corresponding to the meta-stable nonsupersymmetric vacua in four dimensional N=1 supersymmetric SU(N_c) x SU(N_c') x SU(N_c'') gauge theory with a symmetric tensor field, a conjugate symmetric tensor field and bifundamental fields. We also describe the intersecting brane configurations of type IIA string theory corresponding to the nonsupersymmetric meta-stable vacua in the above gauge theory with an antisymmetric tensor field, a conjugate symmetric tensor field, eight fundamental flavors and bifundamentals. These brane configurations consist of NS-branes, D4-branes(and anti D4-branes), D6-branes and O6-planes.Comment: 34pp, 9 figures; Improved the draft and added some footnotes; Figure 1, footnote 7 and captions of Figures 7,8,9 added or improved and to appear in CQ

Meta-Stable Brane Configurations by Adding an Orientifold-Plane to Giveon-Kutasov

In hep-th/0703135, they have found the type IIA intersecting brane configuration where there exist three NS5-branes, D4-branes and anti-D4-branes. By analyzing the gravitational interaction for the D4-branes in the background of the NS5-branes, the phase structures in different regions of the parameter space were studied in the context of classical string theory. In this paper, by adding the orientifold 4-plane and 6-plane to the above brane configuration, we describe the intersecting brane configurations of type IIA string theory corresponding to the meta-stable nonsupersymmetric vacua of these gauge theories.Comment: 21 pp, 6 figures; reduced bytes of figures, DBI action analysis added and to appear in JHE

Harmonic Forms and Deformation of ALC metrics with Spin(7) holonomy

Asymptotically locally conical (ALC) metric of exceptional holonomy has an asymptotic circle bundle structure that accommodates the M theory circle in type IIA reduction. Taking Spin(7) metrics of cohomogeneity one as explicit examples, we investigate deformations of ALC metrics, in particular that change the asymptotic S^1 radius related to the type IIA string coupling constant. When the canonical four form of Spin(7) holonomy is taken to be anti-self-dual, the deformations of Spin(7) metric are related to the harmonic self-dual four forms, which are given by solutions to a system of first order differential equations, due to the metric ansatz of cohomogeneity one. We identify the L^2-normalizable solution that deforms the asymptotic radius of the M theory circle.Comment: 33 pages, no figure, minor corrections, reference adde

Timelike Hopf Duality and Type IIA^* String Solutions

The usual T-duality that relates the type IIA and IIB theories compactified on circles of inversely-related radii does not operate if the dimensional reduction is performed on the time direction rather than a spatial one. This observation led to the recent proposal that there might exist two further ten-dimensional theories, namely type IIA^* and type IIB^*, related to type IIB and type IIA respectively by a timelike dimensional reduction. In this paper we explore such dimensional reductions in cases where time is the coordinate of a non-trivial U(1) fibre bundle. We focus in particular on situations where there is an odd-dimensional anti-de Sitter spacetime AdS_{2n+1}, which can be described as a U(1) bundle over \widetilde{CP}^n, a non-compact version of CP^n corresponding to the coset manifold SU(n,1)/U(n). In particular, we study the AdS_5\times S^5 and AdS_7\times S^4 solutions of type IIB supergravity and eleven-dimensional supergravity. Applying a timelike Hopf T-duality transformation to the former provides a new solution of the type IIA^* theory, of the form \widetilde{CP}^2\times S^1\times S^5. We show how the Hopf-reduced solutions provide further examples of ``supersymmetry without supersymmetry.'' We also present a detailed discussion of the geometrical structure of the Hopf-fibred metric on AdS_{2n+1}, and its relation to the horospherical metric that arises in the AdS/CFT correspondence.Comment: Latex, 26 page

SO(32) Spinors of Type I and Other Solitons on Brane-Antibrane Pair

We construct the SO(32) spinor state in weakly coupled type I string theory as a kink solution of the tachyon field on the D-string - anti-D-string pair and calculate its mass. We also give a description of this system in terms of an exact boundary conformal field theory and show that in this description this state can be regarded as a non-supersymmetric D0-brane in type I string theory. This construction can be generalised to represent the D0-brane in type IIA string theory as a vortex solution of the tachyon field on the membrane anti-membrane pair, and the D-string of type I string theory as a topological soliton of the tachyon field on the D5-brane anti- D5-brane pair.Comment: LaTeX file, 31 page

Strong Coupling Dynamics of Branes from M-theory

We study some aspects of the strong coupling dynamics of Dirichlet six branes, anti- six branes, and orientifold planes by using the equivalence of type IIA string theory and M-theory on S^1. In the strong coupling limit there exists static configuration of brane and anti-brane at arbitrary separation, suspended in an external magnetic field. The mass of the open string stretched between the brane and the anti-brane approaches a finite positive value even when the branes coincide. Similar result is obtained for a Dirichlet six brane on top of an orientifold six plane. We also derive the anomalous gravitational interaction on the brane and the orientifold plane from M-theory.Comment: LaTeX file, 15 pages, section on brane-antibrane interaction revised with some of the results reinterpreted, new references adde