784 research outputs found
Open mirror symmetry for Pfaffian Calabi-Yau 3-folds
We investigate the open mirror symmetry of certain non-complete intersection
Calabi- Yau 3-folds, so called pfaffian Calabi-Yau. We perform the prediction
of the number of disk invariants of several examples by using the direct
integration method proposed recently and the open mirror symmetry. We treat
several pfaffian Calabi-Yau 3-folds in and branes with two
discrete vacua. Some models have the two special points in its moduli space,
around both of which we can consider different A-model mirror partners. We
compute disc invariants for both cases. This study is the first application of
the open mirror symmetry to the compact non-complete intersections in toric
variety.Comment: 64 pages; v2: typos corrected, minor changes, references added; v3:
published version, minor corrections and improvement
A method to polarise antiprotons in storage rings and create polarised antineutrons
An intense circularely polarised photon beam interacts with a cooled
antiproton beam in a storage ring. Due to spin dependent absorption cross
sections for the reaction gamma+antiproton > pi- + antineutron a built-up of
polarisation of the stored antiprotons takes place. Figures-of-merit around 0.1
can be reached in principle over a wide range of antiproton energies. In this
process antineutrons with Polarisation > 70% emerge. The method is presented
for the case of 300 MeV/c cooled antiproton beam
Calculations for Mirror Symmetry with D-branes
We study normal functions capturing D-brane superpotentials on several one-
and two-parameter Calabi-Yau hypersurfaces and complete intersections in
weighted projective space. We calculate in the B-model and interpret the
results using mirror symmetry in the large volume regime, albeit without
identifying the precise A-model geometry in all cases. We identify new classes
of extensions of Picard-Fuchs equations, as well as a novel type of topology
changing phase transition involving quantum D-branes. A 4-d domain wall which
is obtained in one region of closed string moduli space from wrapping a
four-chain interpolating between two Lagrangian submanifolds is, for other
values of the parameters, represented by a disk ending on a single Lagrangian.Comment: 42 page
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
A surprising method for polarising antiprotons
We propose a method for polarising antiprotons in a storage ring by means of
a polarised positron beam moving parallel to the antiprotons. If the relative
velocity is adjusted to the cross section for spin-flip is
as large as about barn as shown by new QED-calculations of
the triple spin-cross sections. Two possibilities for providing a positron
source with sufficient flux density are presented. A polarised positron beam
with a polarisation of 0.70 and a flux density of approximately /(mm s) appears to be feasible by means of a radioactive C
dc-source. A more involved proposal is the production of polarised positrons by
pair production with circularly polarised photons. It yields a polarisation of
0.76 and requires the injection into a small storage ring. Such polariser
sources can be used at low (100 MeV) as well as at high (1 GeV) energy storage
rings providing a time of about one hour for polarisation build-up of about
antiprotons to a polarisation of about 0.18. A comparison with other
proposals show a gain in the figure-of-merit by a factor of about ten.Comment: 13 pages, 8 figures; v2: minor language and signification corrections
v3: (14 pages, 12 figures) major error, nonapplicable polarisation transfer
cross sections replaced by the mandatory spin-flip cross section
D-brane Categories for Orientifolds -- The Landau-Ginzburg Case
We construct and classify categories of D-branes in orientifolds based on
Landau-Ginzburg models and their orbifolds. Consistency of the worldsheet
parity action on the matrix factorizations plays the key role. This provides
all the requisite data for an orientifold construction after embedding in
string theory. One of our main results is a computation of topological field
theory correlators on unoriented worldsheets, generalizing the formulas of Vafa
and Kapustin-Li for oriented worldsheets, as well as the extension of these
results to orbifolds. We also find a doubling of Knoerrer periodicity in the
orientifold context.Comment: 45 pages, 6 figure
The holomorphic anomaly for open string moduli
We complete the holomorphic anomaly equations for topological strings with
their dependence on open moduli. We obtain the complete system by standard path
integral arguments generalizing the analysis of BCOV (Commun. Math. Phys. 165
(1994) 311) to strings with boundaries. We study both the anti-holomorphic
dependence on open moduli and on closed moduli in presence of Wilson lines. By
providing the compactification a' la Deligne-Mumford of the moduli space of
Riemann surfaces with boundaries, we show that the open holomorphic anomaly
equations are structured on the (real codimension one) boundary components of
this space.Comment: 1+14 pages, 6 figures! v2: ref. added v3: section 4 expanded, 1+17
pages, 11 figures!!, to be publ. in JHE
ABCD of Beta Ensembles and Topological Strings
We study beta-ensembles with Bn, Cn, and Dn eigenvalue measure and their
relation with refined topological strings. Our results generalize the familiar
connections between local topological strings and matrix models leading to An
measure, and illustrate that all those classical eigenvalue ensembles, and
their topological string counterparts, are related one to another via various
deformations and specializations, quantum shifts and discrete quotients. We
review the solution of the Gaussian models via Macdonald identities, and
interpret them as conifold theories. The interpolation between the various
models is plainly apparent in this case. For general polynomial potential, we
calculate the partition function in the multi-cut phase in a perturbative
fashion, beyond tree-level in the large-N limit. The relation to refined
topological string orientifolds on the corresponding local geometry is
discussed along the way.Comment: 33 pages, 1 figur
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