458 research outputs found
Topological field theories and their symmetries within the Batalin-Vilkovisky framework
We discuss the algebraic construction of topological models (of both Schwarz- and Witten-type) within the Batalin-Vilkovisky formalism and we elaborate on a simple description of vector supersymmetry within this framework
Perturbative Computation of Glueball Superpotentials for SO(N) and USp(N)
We use the superspace method of hep-th/0211017 to prove the matrix model
conjecture for N=1 USp(N) and SO(N) gauge theories in four dimensions. We
derive the prescription to relate the matrix model to the field theory
computations. We perform an explicit calculation of glueball superpotentials.
The result is consistent with field theory expectations.Comment: 24 pages, 10 figure
On Type II Strings in Two Dimensions
We consider type IIA/B strings in two-dimensions and their projection with
respect to the nilpotent space-time supercharge. Based on the ground ring
structure, we propose a duality between perturbed type II strings and the
topological B-model on deformed Calabi-Yau singularities. Depending on the type
II spectra, one has either the conifold or the suspended pinch point geometry.
Using the corresponding quiver gauge theory, obtained by D-branes wrapping in
the resolved suspended pinch point geometry, we propose the all orders
perturbative partition function.Comment: 1+23 page
Double Dissociation of Format-Dependent and Number-Specific Neurons in Human Parietal Cortex
Based on neuroimaging methods, it is a commonly held view that numerical representation in the human parietal lobes is format independent. We used a transcranial magnetic stimulation adaptation paradigm to examine the existence of functionally segregated overlapping populations of neurons for different numerical formats and to reveal how numerical information is encoded and represented. Based on 2 experiments, we found that right parietal lobe stimulation showed a dissociation between digits and verbal numbers, whereas the left parietal lobe showed a double dissociation between the different numerical formats. Further analysis and modeling also excluded pre- or postrepresentational components as the source of the current effects. These results demonstrate that both parietal lobes are equipped with format-dependent neurons that encode quantity
Wrapped fivebranes and N=2 super Yang-Mills theory
We construct D=10 supergravity solutions corresponding to type IIB fivebranes
wrapping a two-sphere in a Calabi-Yau two-fold. These are related in the IR to
the large N limit of pure N=2 SU(N) super Yang-Mills theory. We show that the
singularities in the IR correspond to the wrapped branes being distributed on a
ring. We analyse the dynamics of a probe fivebrane and show that it
incorporates the full perturbative structure of the gauge theory. For a class
of solutions the two-dimensional moduli space is non-singular and we match the
result for the corresponding slice of the Coulomb branch of the gauge theory.Comment: 24 Latex pages, two figures;v2 typos corrected, references adde
M-Theory solutions with AdS factors
Solutions of D=7 maximal gauged supergravity are constructed with metrics
that are a product of a n-dimensional anti-de Sitter (AdS) space, with
n=2,3,4,5, and certain Einstein manifolds. The gauge fields have the same form
as in the recently constructed solutions describing the near-horizon limits of
M5-branes wrapping supersymmetric cycles. The new solutions do not preserve any
supersymmetry and can be uplifted to obtain new solutions of D=11 supergravity,
which are warped and twisted products of the D=7 metric with a squashed
four-sphere. Some aspects of the stability of the solutions are discussed.Comment: 30 pages. References adde
LOFAR discovery of the fastest-spinning millisecond pulsar in the Galactic field
We report the discovery of PSR J09520607, a 707-Hz binary millisecond
pulsar which is now the fastest-spinning neutron star known in the Galactic
field (i.e., outside of a globular cluster). PSR J09520607 was found using
LOFAR at a central observing frequency of 135 MHz, well below the 300 MHz to 3
GHz frequencies typically used in pulsar searches. The discovery is part of an
ongoing LOFAR survey targeting unassociated Fermi Large Area Telescope
-ray sources. PSR J09520607 is in a 6.42-hr orbit around a very
low-mass companion ( M) and we identify a
strongly variable optical source, modulated at the orbital period of the
pulsar, as the binary companion. The light curve of the companion varies by 1.6
mag from at maximum to , indicating that it is
irradiated by the pulsar wind. Swift observations place a 3- upper
limit on the keV X-ray luminosity of erg
s (using the 0.97 kpc distance inferred from the dispersion measure).
Though no eclipses of the radio pulsar are observed, the properties of the
system classify it as a black widow binary. The radio pulsed spectrum of PSR
J09520607, as determined through flux density measurements at 150 and 350
MHz, is extremely steep with (where ).
We discuss the growing evidence that the fastest-spinning radio pulsars have
exceptionally steep radio spectra, as well as the prospects for finding more
sources like PSR J09520607.Comment: 9 pages, 3 figures, 1 table, published in ApJ letter
Let's Twist Again: General Metrics of G(2) Holonomy from Gauged Supergravity
We construct all complete metrics of cohomogeneity one G(2) holonomy with S^3
x S^3 principal orbits from gauged supergravity. Our approach rests on a
generalization of the twisting procedure used in this framework. It corresponds
to a non-trivial embedding of the special Lagrangian three-cycle wrapped by the
D6-branes in the lower dimensional supergravity. There are constraints that
neatly reduce the general ansatz to a six functions one. Within this approach,
the Hitchin system and the flop transformation are nicely realized in eight
dimensional gauged supergravity.Comment: 31 pages, latex; v2: minor changes, references adde
Holonomy from wrapped branes
Compactifications of M-theory on manifolds with reduced holonomy arise as the
local eleven-dimensional description of D6-branes wrapped on supersymmetric
cycles in manifolds of lower dimension with a different holonomy group.
Whenever the isometry group SU(2) is present, eight-dimensional gauged
supergravity is a natural arena for such investigations. In this paper we use
this approach and review the eleven dimensional description of D6-branes
wrapped on coassociative 4-cycles, on deformed 3-cycles inside Calabi-Yau
threefolds and on Kahler 4-cycles.Comment: 1+8 pages, Latex. Proceedings of the Leuven workshop, 2002. v2:
Corrected typos in equations (4)-(8
- …