1,879 research outputs found
On the Instanton Contributions to the Masses and Couplings of Singlets
We consider the gauge neutral matter in the low--energy effective action for
string theory compactification on a \cym\ with world--sheet
supersymmetry. At the classical level these states (the \sing's of )
correspond to the cohomology group H^1(\M,{\rm End}\>T). We examine the first
order contribution of instantons to the mass matrix of these particles. In
principle, these corrections depend on the \K\ parameters through factors
of the form e^{2\p i t_i} and also depend on the complex structure
parameters. For simplicity we consider in greatest detail the quintic threefold
\cp4[5]. It follows on general grounds that the total mass is often, and
perhaps always, zero. The contribution of individual instantons is however
nonzero and the contribution of a given instanton may develop poles associated
with instantons coalescing for certain values of the complex structure. This
can happen when the underlying \cym\ is smooth. Hence these poles must cancel
between the coalescing instantons in order that the superpotential be finite.
We examine also the \Y\ couplings involving neutral matter \ysing\ and neutral
and charged fields \ymix, which have been little investigated even though they
are of phenomenological interest. We study the general conditions under which
these couplings vanish classically. We also calculate the first--order
world--sheet instanton correction to these couplings and argue that these also
vanish.Comment: 40 pages, plain TeX with epsf, one uuencoded figur
A Class of N=1 Supersymmetric RG Flows from Five-dimensional N = 8 Supergravity
We consider the holographic dual of a general class of N=1* flows in which
all three chiral multiplets have independent masses, and in which the
corresponding Yang-Mills scalars can develop particular
supersymmetry-preserving vevs. We also allow the gaugino to develop a vev. This
leads to a six parameter subspace of the supergravity scalar action, and we
show that this is a consistent truncation, and obtain a superpotential that
governs the N=1* flows on this subspace. We analyse some of the structure of
the superpotential, and check consistency with the asymptotic behaviour near
the UV fixed point. We show that the dimensions of the six couplings obey a sum
rule all along the N=1* flows. We also show how our superpotential describes
part of the Coulomb branch of the non-trivial N=1 fixed point theory.Comment: 14 pages; harvmac. New version has only minor correction
Deformed Quantum Cohomology and (0,2) Mirror Symmetry
We compute instanton corrections to correlators in the genus-zero topological
subsector of a (0,2) supersymmetric gauged linear sigma model with target space
P1xP1, whose left-moving fermions couple to a deformation of the tangent
bundle. We then deduce the theory's chiral ring from these correlators, which
reduces in the limit of zero deformation to the (2,2) ring. Finally, we compare
our results with the computations carried out by Adams et al.[ABS04] and Katz
and Sharpe[KS06]. We find immediate agreement with the latter and an
interesting puzzle in completely matching the chiral ring of the former.Comment: AMSLatex, 30 pages, one eps figure. V4: typos corrected, final
version appearing in JHE
Field condensations and Noncritical String for c>1
Quantum theory of 2d gravity for is examined as a non-critical string
theory by taking account of the loop-correction of open strings whose end
points are on the 2d world surface of the closed string. This loop-correction
leads to a conformal anomaly, and we obtain a modified target-space action
which implies a new phase of the non-critical closed-string. In this phase, the
dual field of the gauge field, which lives on the boundary, condenses and the
theory can be extended to without any instability.Comment: 17 pages, Latex, no figur
Recommended from our members
FOREVER: Fault/intrusiOn REmoVal through Evolution & Recovery
The goal of the FOREVER project is to develop a service for Fault/intrusiOn REmoVal through Evolution & Recovery. In order to achieve this goal, our work addresses three main tasks: the definition of the FOREVER service architecture; the analysis of how diversity techniques can improve resilience; and the evaluation of the FOREVER service. The FOREVER service is an important contribution to intrustion-tolerant replication middleware and significantly enhances the resilience
Fermionic characters for graded parafermions
Fermionic-type character formulae are presented for charged
irreduciblemodules of the graded parafermionic conformal field theory
associated to the coset . This is obtained by counting the
weakly ordered `partitions' subject to the graded exclusion principle.
The bosonic form of the characters is also presented.Comment: 24 p. This corrects typos (present even in the published version) in
eqs (4.4), (5.23), (5.24) and (C.4
A Possible IIB Superstring Matrix Model with Euler Characteristic and a Double Scaling Limit
We show that a recently proposed Yang-Mills matrix model with an auxiliary
field, which is a candidate for a non-perturbative description of type IIB
superstrings, captures the Euler characteristic of moduli space of Riemann
surfaces. This happens at the saddle point for the Yang-Mills field. It turns
out that the large-n limit in this matrix model corresponds to a double scaling
limit in the Penner model.Comment: 5 pages, LaTe
Semirigid Geometry
We provide an intrinsic description of -super \RS s and -\SR\
surfaces. Semirigid surfaces occur naturally in the description of topological
gravity as well as topological supergravity. We show that such surfaces are
obtained by an integrable reduction of the structure group of a complex
supermanifold. We also discuss the \s moduli spaces of -\SR\ surfaces and
their relation to the moduli spaces of -\s\ \RS s.Comment: 29p
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