947 research outputs found
Type IIA orientifold compactification on SU(2)-structure manifolds
We investigate the effective theory of type IIA string theory on
six-dimensional orientifold backgrounds with SU(2)-structure. We focus on the
case of orientifolds with O6-planes, for which we compute the bosonic effective
action in the supergravity approximation. For a generic SU(2)-structure
background, we find that the low-energy effective theory is a gauged N=2
supergravity where moduli in both vector and hypermultiplets are charged. Since
all these supergravities descend from a corresponding N=4 background, their
scalar target space is always a quotient of a SU(1,1)/U(1) x
SO(6,n)/SO(6)xSO(n) coset, and is therefore also very constrained.Comment: 31 pages; v2: local report number adde
Surface Operator, Bubbling Calabi-Yau and AGT Relation
Surface operators in N=2 four-dimensional gauge theories are interesting
half-BPS objects. These operators inherit the connection of gauge theory with
the Liouville conformal field theory, which was discovered by Alday, Gaiotto
and Tachikawa. Moreover it has been proposed that toric branes in the A-model
topological strings lead to surface operators via the geometric engineering. We
analyze the surface operators by making good use of topological string theory.
Starting from this point of view, we propose that the wave-function behavior of
the topological open string amplitudes geometrically engineers the surface
operator partition functions and the Gaiotto curves of corresponding gauge
theories. We then study a peculiar feature that the surface operator
corresponds to the insertion of the degenerate fields in the conformal field
theory side. We show that this aspect can be realized as the geometric
transition in topological string theory, and the insertion of a surface
operator leads to the bubbling of the toric Calabi-Yau geometry.Comment: 36 pages, 14 figures. v2: minor changes and typos correcte
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Visuo-spatial cognition in Williams syndrome: Reviewing and accounting for the strengths and weaknesses in performance
Individuals with Williams syndrome typically show relatively poor visuo-spatial abilities in comparison to stronger verbal skills. However, individuals' level of performance is not consistent across all visuo-spatial tasks. The studies assessing visuo-spatial functioning in Williams syndrome are critically reviewed, in order to provide a clear pattern of the relative difficulty of these tasks. This prompts a possible explanation of the variability in performance seen which focuses on the processing demands of some of these tasks. Individuals with Williams syndrome show an atypical processing style on tests of construction, which does not affect tests of perception
Electromyographic Analysis in Elite Swimmers with Shoulder Pain during a Functional Task
The purpose of study was to determine and compare electromyographic activity of selected shoulder girdle muscles in elite swimmers with and without shoulder pain. Twelve professional swimmers with shoulder pain (mean age: 18.55±3.16 years, body mass: 74.33±2.91 kg, and height: 179.00±5.29cm) and twelve swimmers without pain (mean age: 18.11±1.61 years, body weight: 73.33±6.06 kg, height: 178.33±5.07cm) were recruited. Surface electromyography signals were collected from seven upper limb muscles during a task: participants were instructed to mark points with a pen within each of the 3 circles counterclockwise. The normalised root-mean-square value was used to determine the muscular activation. Swimmers with shoulder pain demonstrated greater activation of the upper trapezius (pain group mean: 28.04±10.37, control group mean: 13.40±06.04; p=0.002, partial eta square: 0.455), serratus anterior (pain group mean: 30.78±20.09, control group mean: 13.30±5.52; p=0.023, partial eta square: 0.283) and latissimus dorsi (pain group mean: 27.05±17.87, control group mean: 4.99±3.90; p=0.002, partial eta square: 0.450) muscles. There was no difference (p>0.05) in the activation of the middle and lower trapezius, middle deltoid and sternocleidomastoid. The altered muscle activation patterns may contribute to the painful shoulder in elite swimmers and need to be considered within the rehabilitation interventions
Taming open/closed string duality with a Losev trick
A target space string field theory formulation for open and closed B-model is
provided by giving a Batalin-Vilkovisky quantization of the holomorphic
Chern-Simons theory with off-shell gravity background. The target space
expression for the coefficients of the holomorphic anomaly equation for open
strings are obtained. Furthermore, open/closed string duality is proved from a
judicious integration over the open string fields. In particular, by
restriction to the case of independence on continuous open moduli, the shift
formulas of [7] are reproduced and shown therefore to encode the data of a
closed string dual.Comment: 22 pages, no figures; v.2 Refs. and a comment added
Open string wavefunctions in flux compactifications
We consider compactifications of type I supergravity on manifolds with SU(3)
structure, in the presence of RR fluxes and magnetized D9-branes, and analyze
the generalized Dirac and Laplace-Beltrami operators associated to the D9-brane
worldvolume fields. These compactifications are T-dual to standard type IIB
toroidal orientifolds with NSNS and RR 3-form fluxes and D3/D7 branes. By using
techniques of representation theory and harmonic analysis, the spectrum of open
string wavefunctions can be computed for Lie groups and their quotients, as we
illustrate with explicit twisted tori examples. We find a correspondence
between irreducible unitary representations of the Kaloper-Myers algebra and
families of Kaluza-Klein excitations. We perform the computation of 2- and
3-point couplings for matter fields in the above flux compactifications, and
compare our results with those of 4d effective supergravity.Comment: 89 pages, 4 figures. v3: more typos corrected, version published in
JHE
Heterotic Flux Attractors
We find attractor equations describing moduli stabilization for heterotic
compactifications with generic SU(3)-structure. Complex structure and K\"ahler
moduli are treated on equal footing by using SU(3)xSU(3)-structure at
intermediate steps. All independent vacuum data, including VEVs of the
stabilized moduli, is encoded in a pair of generating functions that depend on
fluxes alone. We work out an explicit example that illustrates our methods.Comment: 37 pages, references and clarifications adde
Moduli Stabilization and Cosmology of Type IIB on SU(2)-Structure Orientifolds
We consider type IIB flux compactifications on six-dimensional
SU(2)-structure manifolds with O5- and O7-planes. These six-dimensional spaces
allow not only for F_3 and H_3 fluxes but also for F_1 and F_5 fluxes. We
derive the four-dimensional N=1 scalar potential for such compactifications and
present one explicit example of a fully stabilized AdS vacuum with large volume
and small string coupling. We then discuss cosmological aspects of these
compactifications and derive several no-go theorems that forbid dS vacua and
slow-roll inflation under certain conditions. We also study concrete examples
of cosets and twisted tori and find that our no-go theorems forbid dS vacua and
slow-roll inflation in all but one of them. For the latter we find a dS
critical point with \epsilon numerically zero. However, the point has two
tachyons and eta-parameter \eta \approx -3.1.Comment: 35 pages + appendices, LaTeX2e; v2: numerical dS extremum added,
typos corrected, references adde
On N = 2 Truncations of IIB on T^{1,1}
We study the N=4 gauged supergravity theory which arises from the consistent
truncation of IIB supergravity on the coset T^{1,1}. We analyze three N=2
subsectors and in particular we clarify the relationship between true
superpotentials for gauged supergravity and certain fake superpotentials which
have been widely used in the literature. We derive a superpotential for the
general reduction of type I supergravity on T^{1,1} and this together with a
certain solution generating symmetry is tantamount to a superpotential for the
baryonic branch of the Klebanov-Strassler solution.Comment: 32 pages, v2:references adde
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