655 research outputs found
Nonrenormalization Theorem for Gauge Coupling in 2+1D
We prove that \be-function of the gauge coupling in gauge theory
coupled to any renormalizable system of spinor and scalar fields is zero. This
result holds both when the gauge field action is the Chern-Simons action and
when it is the topologically massive action.Comment: 8 pages, LaTeX file, CALT-68-191
D-branes in Topological Minimal Models: the Landau-Ginzburg Approach
We study D-branes in topologically twisted N=2 minimal models using the
Landau-Ginzburg realization. In the cases of A and D-type minimal models we
provide what we believe is an exhaustive list of topological branes and compute
the corresponding boundary OPE algebras as well as all disk correlators. We
also construct examples of topological branes in E-type minimal models. We
compare our results with the boundary state formalism, where possible, and find
agreement.Comment: 29 pages, late
The Landau-Ginzburg to Calabi-Yau Dictionary for D-Branes
Based on work by Orlov, we give a precise recipe for mapping between B-type
D-branes in a Landau-Ginzburg orbifold model (or Gepner model) and the
corresponding large-radius Calabi-Yau manifold. The D-branes in Landau-Ginzburg
theories correspond to matrix factorizations and the D-branes on the Calabi-Yau
manifolds are objects in the derived category. We give several examples
including branes on quotient singularities associated to weighted projective
spaces. We are able to confirm several conjectures and statements in the
literature.Comment: 24 pages, refs added + minor correctio
Boundary states, matrix factorisations and correlation functions for the E-models
The open string spectra of the B-type D-branes of the N=2 E-models are
calculated. Using these results we match the boundary states to the matrix
factorisations of the corresponding Landau-Ginzburg models. The identification
allows us to calculate specific terms in the effective brane superpotential of
E_6 using conformal field theory methods, thereby enabling us to test results
recently obtained in this context.Comment: 20 pages, no figure
Tensor Product and Permutation Branes on the Torus
We consider B-type D-branes in the Gepner model consisting of two minimal
models at k=2. This Gepner model is mirror to a torus theory. We establish the
dictionary identifying the B-type D-branes of the Gepner model with A-type
Neumann and Dirichlet branes on the torus.Comment: 26 page
D-branes in Toroidal Orbifolds and Mirror Symmetry
We study D-branes extended in T^2/Z_4 using the mirror description as a
tensor product of minimal models. We describe branes in the mirror both as
boundary states in minimal models and as matrix factorizations in the
corresponding Landau-Ginzburg model. We isolate a minimal set of branes and
give a geometric interpretation of these as D1-branes constrained to the
orbifold fixed points. This picture is supported both by spacetime arguments
and by the explicit construction of the boundary states, adapting the known
results for rational boundary states in the minimal models. Similar techniques
apply to a larger class of toroidal orbifolds.Comment: 30 pages, 2 figure
N=2 Liouville Theory with Boundary
We study N=2 Liouville theory with arbitrary central charge in the presence
of boundaries. After reviewing the theory on the sphere and deriving some
important structure constants, we investigate the boundary states of the theory
from two approaches, one using the modular transformation property of annulus
amplitudes and the other using the bootstrap of disc two-point functions
containing degenerate bulk operators. The boundary interactions describing the
boundary states are also proposed, based on which the precise correspondence
between boundary states and boundary interactions is obtained. The open string
spectrum between D-branes is studied from the modular bootstrap approach and
also from the reflection relation of boundary operators, providing a
consistency check for the proposal.Comment: 1+48 pages, no figure. typos corrected and references added. the
version to appear in JHE
Permutation branes and linear matrix factorisations
All the known rational boundary states for Gepner models can be regarded as
permutation branes. On general grounds, one expects that topological branes in
Gepner models can be encoded as matrix factorisations of the corresponding
Landau-Ginzburg potentials. In this paper we identify the matrix factorisations
associated to arbitrary B-type permutation branes.Comment: 43 pages. v2: References adde
D-branes on general N=1 backgrounds: superpotentials and D-terms
We study the dynamics governing space-time filling D-branes on Type II flux
backgrounds preserving four-dimensional N=1 supersymmetry. The four-dimensional
superpotentials and D-terms are derived. The analysis is kept on completely
general grounds thanks to the use of recently proposed generalized
calibrations, which also allow one to show the direct link of the
superpotentials and D-terms with BPS domain walls and cosmic strings
respectively. In particular, our D-brane setting reproduces the tension of
D-term strings found from purely four-dimensional analysis. The holomorphicity
of the superpotentials is also studied and a moment map associated to the
D-terms is proposed. Among different examples, we discuss an application to the
study of D7-branes on SU(3)-structure backgrounds, which reproduces and
generalizes some previous results.Comment: 50 pages; v2: table of contents, some clarifications and references
added; v3: typos corrected and references adde
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