1,184 research outputs found
Holographic Duals of Long Open Strings
We study the holographic map between long open strings, which stretch between
D-branes separated in the bulk space-time, and operators in the dual boundary
theory. We focus on a generalization of the Sakai-Sugimoto holographic model of
QCD, where the simplest chiral condensate involves an operator of this type.
Its expectation value is dominated by a semi-classical string worldsheet, as
for Wilson loops. We also discuss the deformation of the model by this
operator, and in particular its effect on the meson spectrum. This deformation
can be thought of as a generalization of a quark mass term to strong coupling.
It leads to the first top-down holographic model of QCD with a non-Abelian
chiral symmetry which is both spontaneously and explicitly broken, as in QCD.
Other examples we study include half-supersymmetric open Wilson lines, and
systems of D-branes ending on NS5-branes, which can be analyzed using
worldsheet methods.Comment: 35 pages, 4 figures, harvmac. v2: added reference
Duality and other Exotic Gauge Dynamics in Softly Broken Supersymmetric QCD
We analyze the theory of softly broken supersymmetric . Exotic behavior
like spontaneously broken baryon number, massless composite fermions and
Seiberg's duality seems to persist also in the presence of (small) soft
supersymmetry breaking. We argue that certain, specially tailored, lattice
simulations may be able to detect the novel phenomena. Most of the exotic
behavior does not survive the decoupling limit of large SUSY breaking
parameters.Comment: 13 page
Open String Moduli in KKLT Compactifications
In the Kachru-Kallosh-Linde-Trivedi (KKLT) de-Sitter construction one
introduces an anti-D3-brane that breaks the supersymmetry and leads to a
positive cosmological constant. In this paper we investigate the open string
moduli associated with this anti-D3-brane, corresponding to its position on the
3-sphere at the tip of the deformed conifold. We show that in the KKLT
construction these moduli are very light, and we suggest a possible way to give
these moduli a large mass by putting orientifold planes in the KKLT "throat".Comment: harvmac, 22 page
The black hole in the throat - thermodynamics of strongly coupled cascading gauge theories
We numerically construct black hole solutions corresponding to the
deconfined, chirally symmetric phase of strongly coupled cascading gauge
theories at various temperatures. We compute the free energy as a function of
the temperature, and we show that it becomes positive below some critical
temperature, indicating the possibility of a first order phase transition at
which the theory deconfines and restores the chiral symmetry.Comment: 45 pages, 13 figures, latex. v2: typo fixe
Holographic renormalization of cascading gauge theories
We perform a holographic renormalization of cascading gauge theories.
Specifically, we find the counter-terms that need to be added to the
gravitational action of the backgrounds dual to the cascading theory of
Klebanov and Tseytlin, compactified on an arbitrary four-manifold, in order to
obtain finite correlation functions (with a limited set of sources). We show
that it is possible to truncate the action for deformations of this background
to a five dimensional system coupling together the metric and four scalar
fields. Somewhat surprisingly, despite the fact that these theories involve an
infinite number of high-energy degrees of freedom, we find finite answers for
all one-point functions (including the conformal anomaly). We compute
explicitly the renormalized stress tensor for the cascading gauge theories at
high temperature and show how our finite answers are consistent with the
infinite number of degrees of freedom. Finally, we discuss ambiguities
appearing in the holographic renormalization we propose for the cascading gauge
theories; our finite results for the one-point functions have some ambiguities
in curved space (including the conformal anomaly) but not in flat space.Comment: 65 pages (46 pages + appendix), latex. v2: added references. v3:
added a reference and a footnot
Review of the Cardinalfishes (Perciformes: Apogonidae) of the Red Sea
Twelve genera and 54 species of cardinalfishes are reported from the Red Sea. The Red Sea cardinalfishes include: Apogon annularis RĂŒppell, A. apogonides (Bleeker), Apogon bryx Fraser, A. campbelli Smith, A. coccineus RĂŒppell, A. cookii Macleay, A. cyanosoma Bleeker, A. erythrosoma n. sp., A. exostigma (Jordan & Starks), A. fleurieu (LacepĂšde), A. fraenatus Valenciennes, A. guamensis Valenciennes, A. gularis Fraser & Lachner, A. heptastygma Cuvier, A. isus Randall & Böhlke, A. kallopterus Bleeker, A. leptacanthus Bleeker, A. multitaeniatus Cuvier, A. nigrofasciatus Lachner, A. pharaonis Bellotti, A. pselion Randall, Fraser & Lachner, A. pseudotaeniatus Gon, A. quadrifasciatus Cuvier, A. queketti Gilchrist, A. semiornatus Peters, A. smithi (Kotthaus), A. spilurus Regan, A. taeniatus Cuvier, A. talboti Smith, A. timorensis Bleeker, A. zebrinus Fraser, Randall & Lachner, Apogonichthys perdix Bleeker, Archamia bilineata Gon & Randall, Archamia fucata (Cantor), Archamia lineolata (Cuvier), Cercamia eremia (Allen), Cheilodipterus lachneri Klausewitz, C. lineatus (ForsskĂ„l), C. macrodon LacepPde, C. novemstriatus (RĂŒppell), C. pygmaios Gon, C. quinquelineatus Cuvier, Foa fo Jordan & Seale, Fowleria aurita (Valenciennes), F. marmorata (Alleyne & Macleay), F. vaiulae (Jordan & Seale), F. variegata (Valenciennes), Neamia octospina Smith & Radcliffe, Pseudamia gelatinosa Smith, Rhabdamia cypselura Weber, R. nigrimentum (Smith), R. spilota Allen & Kuiter, Siphamia permutata Klausewitz, and Sphaeramia orbicularis (Cuvier). Twelve (22%) of the apogonid species are endemic. Seven species, i.e. Apogon apogonides, A. campbelli, A. erythrosoma, A. talboti, Foa fo, Rhabdamia spilota and Sphaeramia orbicularis, are new to the Red Sea. Apogon coccineus of previous authors is a complex of three species, including campbelli Smith and erythrosoma n. sp. The dark-striped species of Apogon of the Red Sea previously identified as angustatus, endekataenia, fasciatus, or novemfasciatus are cookii and nigrofasciatus. Red Sea apogonids identified by previous authors as Apogon bandanensis, monochrous, nubilus and savayensis, are guamensis and zebrinus. Apogon micromaculatus Kotthaus is A. spilurus Regan. The specimen of Apogon kiensis reported by Smith (1961) from the Red Sea is A. bryx, recently described from the Philippines. In the genus Fowleria, polystigma (Bleeker) and punctulata (RĂŒppell) are junior synonyms of variegata (Valenciennes). F. abocellata Goren & Karplus is a junior synonym of vaiulae (Jordan & Seale), and isostigma (Jordan & Seale) does not occur in the Red Sea. Apogon cupreus and A. latus, both of Cuvier, are unidentifiable. A. hyalosoma and A. taeniophorus are doubtful records
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A kinematic classification of the cosmic web
A new approach for the classification of the cosmic web is presented. In
extension of the previous work of Hahn et al. (2007) and Forero-Romero et al.
(2009) the new algorithm is based on the analysis of the velocity shear tensor
rather than the gravitational tidal tensor. The procedure consists of the
construction of the the shear tensor at each (grid) point in space and the
evaluation of its three eigenvectors. A given point is classified to be either
a void, sheet, filament or a knot according to the number of eigenvalues above
a certain threshold, 0, 1, 2, or 3 respectively. The threshold is treated as a
free parameter that defines the web. The algorithm has been applied to a dark
matter only, high resolution simulation of a box of side-length 64Mpc
and N = particles with the framework of the WMAP5/LCDM model. The
resulting velocity based cosmic web resolves structures down to <0.1Mpc
scales, as opposed to the ~1Mpc scale of the tidal based web. The
under-dense regions are made of extended voids bisected by planar sheets, whose
density is also below the mean. The over-dense regions are vastly dominated by
the linear filaments and knots. The resolution achieved by the velocity based
cosmic web provides a platform for studying the formation of halos and galaxies
within the framework of the cosmic web.Comment: 8 pages, 4 Figures, MNRAS Accepted 2012 June 19. Received 2012 May
10; in original form 2011 August 2
A first order deconfinement transition in large N Yang-Mills theory on a small 3-sphere
We give an analytic demonstration that the 3+1 dimensional large N SU(N) pure
Yang-Mills theory, compactified on a small 3-sphere so that the coupling
constant at the compactification scale is very small, has a first order
deconfinement transition as a function of temperature. We do this by explicitly
computing the relevant terms in the canonical partition function up to 3-loop
order; this is necessary because the leading (1-loop) result for the phase
transition is precisely on the borderline between a first order and a second
order transition. Since numerical work strongly suggests that the infinite
volume large N theory also has a first order deconfinement transition, we
conjecture that the phase structure is independent of the size of the 3-sphere.
To deal with divergences in our calculations, we are led to introduce a novel
method of regularization useful for nonabelian gauge theory on a 3-sphere.Comment: 63 pages (40 pages + 2 appendices), 6 figures, harvmac. v2: minor
correction
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