Type IIA Orientifold Limit of M-Theory on Compact Joyce 8-Manifold of Spin(7)-Holonomy

We show that M-theory compactified on a compact Joyce 8-manifold of $Spin(7)$-holonomy, which yields an effective theory in $D = 3$ with $\N$ = 1 supersymmetry, admits at some special points in it moduli space a description in terms of type IIA theory on an orientifold of compact Joyce 7-manifold of $G_2$-holonomy. We find the evidence in favour of this duality by computing the massless spectra on both M-thory side and type IIA side. For the latter, we compute the massless spectra by going to the orbifold limit of the Joyce 7-manifold.Comment: 26 pages, 2 eps figures, Latex file, two references and one footnote added, corrected some typo

On the Fock space for nonrelativistic anyon fields and braided tensor products

We realize the physical N-anyon Hilbert spaces, introduced previously via unitary representations of the group of diffeomorphisms of the plane, as N-fold braided-symmetric tensor products of the 1-particle Hilbert space. This perspective provides a convenient Fock space construction for nonrelativistic anyon quantum fields along the more usual lines of boson and fermion fields, but in a braided category. We see how essential physical information is thus encoded. In particular we show how the algebraic structure of our anyonic Fock space leads to a natural anyonic exclusion principle related to intermediate occupation number statistics, and obtain the partition function for an idealised gas of fixed anyonic vortices.Comment: Added some references, more explicit formulae for the discrete case and remark on partition function. 25 pages latex, no figure

Comments on M Theory Dynamics on G2 Holonomy Manifolds

We study the dynamics of M-theory on G2 holonomy manifolds, and consider in detail the manifolds realized as the quotient of the spin bundle over S^3 by discrete groups. We analyse, in particular, the class of quotients where the triality symmetry is broken. We study the structure of the moduli space, construct its defining equations and show that three different types of classical geometries are interpolated smoothly. We derive the N=1 superpotentials of M-theory on the quotients and comment on the membrane instanton physics. Finally, we turn on Wilson lines that break gauge symmetry and discuss some of the implications.Comment: 21pages, Latex2e. v2: minor change

Towards A Topological G_2 String

We define new topological theories related to sigma models whose target space is a 7 dimensional manifold of G_2 holonomy. We show how to define the topological twist and identify the BRST operator and the physical states. Correlation functions at genus zero are computed and related to Hitchin's topological action for three-forms. We conjecture that one can extend this definition to all genus and construct a seven-dimensional topological string theory. In contrast to the four-dimensional case, it does not seem to compute terms in the low-energy effective action in three dimensions.Comment: 15 pages, To appear in the proceedings of Cargese 2004 summer schoo

Rotating membranes on G_2 manifolds, logarithmic anomalous dimensions and N=1 duality

We show that the $E-S \sim \log S$ behaviour found for long strings rotating on $AdS_5\times S^5$ may be reproduced by membranes rotating on $AdS_4\times S^7$ and on a warped $AdS_5$ M-theory solution. We go on to obtain rotating membrane configurations with the same $E-K \sim \log K$ relation on $G_2$ holonomy backgrounds that are dual to ${\mathcal{N}}=1$ gauge theories in four dimensions. We study membrane configurations on $G_2$ holonomy backgrounds systematically, finding various other Energy-Charge relations. We end with some comments about strings rotating on warped backgrounds.Comment: 1+44 pages. Latex. No figures. Minor corrections to make all membrane configurations consistent. One configuration is now noncompac

Let's Twist Again: General Metrics of G(2) Holonomy from Gauged Supergravity

We construct all complete metrics of cohomogeneity one G(2) holonomy with S^3 x S^3 principal orbits from gauged supergravity. Our approach rests on a generalization of the twisting procedure used in this framework. It corresponds to a non-trivial embedding of the special Lagrangian three-cycle wrapped by the D6-branes in the lower dimensional supergravity. There are constraints that neatly reduce the general ansatz to a six functions one. Within this approach, the Hitchin system and the flop transformation are nicely realized in eight dimensional gauged supergravity.Comment: 31 pages, latex; v2: minor changes, references adde

Kahler Independence of the G2-MSSM

The G2-MSSM is a model of particle physics coupled to moduli fields with interesting phenomenology both for colliders and astrophysical experiments. In this paper we consider a more general model - whose moduli Kahler potential is a completely arbitrary G2-holonomy Kahler potential and whose matter Kahler potential is also more general. We prove that the vacuum structure and spectrum of BSM particles is largely unchanged in this much more general class of theories. In particular, gaugino masses are still supressed relative to the gravitino mass and moduli masses. We also consider the effects of higher order corrections to the matter Kahler potential and find a connection between the nature of the LSP and flavor effects.Comment: Final version, matches the version published in JHE

Bending Tests of Hat Sections with Multiple Longitudinal Stiffeners

This paper is the first in a series of articles that report findings of the authors investigation into the behavior of cold formed steel hat sections in bending with multiple intermediate longitudinal stiffeners. Presented in this paper is the test program that was carried out at the University of Waterloo as part of a two year research program. It is known that sections with multiple intermediate stiffeners can fail either in a local sub-element buckling mode, or alternatively, can experience an overall plate buckling mode of failure. Although both failure modes were examined, the main objective was to develop a consistently accurate and practical method of predicting the ultimate bending strength of sections which failed in overall plate buckling. Recent testing carried out by previous researchers indicates that the bending resistance of multiple stiffened cold formed steel members which fail in overall plate buckling is too conservatively predicted by the current Canadian design standard (S136-94). These researchers have also shown that the American design specification (AlSI 96) is unconservative for the same sections. Data from 18 previous test specimens were compiled and supplemented with 94 additional tests carried out at the University of Waterloo, encompassing a range of section dimensions and material properties. All test specimens were simply supported and subjected to uniformly distributed loading. The Waterloo test program consisted of hat sections that failed primarily in overall plate buckling and in a few cases also in local sub-element buckling of the compression flange. Only six of the 112 specimens were observed to have failed in local sub-element buckling, while the remainder experienced overall plate buckling at failure

Analysis of Hat Sections with Multiple Intermediate Longitudinal Stiffeners

This paper is the second paper by the authors on the subject of the behavior of cold formed steel hat sections in bending with multiple intermediate longitudinal stiffeners. The first paper, also contained in these Proceedings, deals with the test results only (Acharya and Schuster, 1998). Presented in this paper is the analysis associated with the test program that was conducted at the University of Waterloo. The main objective was to develop a consistently accurate and practical method of predicting the ultimate bending strength of sections that fail in overall plate buckling. Recent testing carried out by previous researchers indicates that the bending resistance of multiple stiffened cold formed steel members which fail in overall plate buckling is too conservatively predicted by the current Canadian design standard (S136-94). These researchers have also shown that the American design specification (A1S1 96) is also unconservative for the same sections. This investigation primarily includes a theoretical study that is substantiated with the experimental data summarized in the first paper. The current North American design methods were evaluated with respect to their ability to predict the strength of the test specimens. Based on the work by Lind (Lind, 1973), which is shown to adequately predict the strength of sections that experience overall plate buckling, an alternate design method for strength determination is presented