7,018 research outputs found

### Superconformal defects in the tricritical Ising model

We study superconformal defect lines in the tricritical Ising model in 2
dimensions. By the folding trick, a superconformal defect is mapped to a
superconformal boundary of the N=1 superconformal unitary minimal model of
c=7/5 with D_6-E_6 modular invariant. It turns out that the complete set of the
boundary states of c=7/5 D_6-E_6 model cannot be interpreted as the consistent
set of superconformal defects in the tricritical Ising model since it does not
contain the "no defect" boundary state. Instead, we find a set of 18 consistent
superconformal defects including "no defect" and satisfying the Cardy
condition. This set also includes some defects which are not purely
transmissive or purely reflective.Comment: 25 pages, 3 figures. v2: typos corrected. v3: clarification about
spin structure aligned theory added, references adde

### 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-brane superpotentials and RG flows on the quintic

The behaviour of D2-branes on the quintic under complex structure
deformations is analysed by combining Landau-Ginzburg techniques with methods
from conformal field theory. It is shown that the boundary renormalisation
group flow induced by the bulk deformations is realised as a gradient flow of
the effective space time superpotential which is calculated explicitly to all
orders in the boundary coupling constant.Comment: 24 pages, 1 figure, v2:Typo in (3.14) correcte

### Moduli Webs and Superpotentials for Five-Branes

We investigate the one-parameter Calabi-Yau models and identify families of
D5-branes which are associated to lines embedded in these manifolds. The moduli
spaces are given by sets of Riemann curves, which form a web whose intersection
points are described by permutation branes. We arrive at a geometric
interpretation for bulk-boundary correlators as holomorphic differentials on
the moduli space and use this to compute effective open-closed superpotentials
to all orders in the open string couplings. The fixed points of D5-brane moduli
under bulk deformations are determined.Comment: 41 pages, 1 figur

### Defect Perturbations in Landau-Ginzburg Models

Perturbations of B-type defects in Landau-Ginzburg models are considered. In
particular, the effect of perturbations of defects on their fusion is analyzed
in the framework of matrix factorizations. As an application, it is discussed
how fusion with perturbed defects induces perturbations on boundary conditions.
It is shown that in some classes of models all boundary perturbations can be
obtained in this way. Moreover, a universal class of perturbed defects is
constructed, whose fusion under certain conditions obey braid relations. The
functors obtained by fusing these defects with boundary conditions are twist
functors as introduced in the work of Seidel and Thomas.Comment: 46 page

### Emergence of Quantum Correlations from Non-Locality Swapping

By studying generalized non-signalling theories, the hope is to find out what
makes quantum mechanics so special. In the present paper, we revisit the
paradigmatic model of non-signalling boxes and introduce the concept of a
genuine box. This will allow us to present the first generalized non-signalling
model featuring quantum-like dynamics. In particular, we present the coupler, a
device enabling non-locality swapping, the analogue of quantum entanglement
swapping, as well as teleportation. Remarkably, part of the boundary between
quantum and post-quantum correlations emerges in our study.Comment: 5 pages. 6 figures. Minor Revisions. To appear in PR

### Opening Mirror Symmetry on the Quintic

Aided by mirror symmetry, we determine the number of holomorphic disks ending
on the real Lagrangian in the quintic threefold. The tension of the domainwall
between the two vacua on the brane, which is the generating function for the
open Gromov-Witten invariants, satisfies a certain extension of the
Picard-Fuchs differential equation governing periods of the mirror quintic. We
verify consistency of the monodromies under analytic continuation of the
superpotential over the entire moduli space. We reproduce the first few
instanton numbers by a localization computation directly in the A-model, and
check Ooguri-Vafa integrality. This is the first exact result on open string
mirror symmetry for a compact Calabi-Yau manifold.Comment: 26 pages. v2: minor corrections and improvement

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