368 research outputs found
Gauge/gravity duality and the interplay of various fractional branes
We consider different types of fractional branes on a Z_2 orbifold of the
conifold and analyze in detail the corresponding gauge/gravity duality. The
gauge theory possesses a rich and varied dynamics, both in the UV and in the
IR. We find the dual supergravity solution which contains both untwisted and
twisted 3-form fluxes, related to what are known as deformation and N=2
fractional branes respectively. We analyze the resulting RG flow from the
supergravity perspective, by developing an algorithm to easily extract it. We
find hints of a generalization of the familiar cascade of Seiberg dualities due
to a non-trivial interplay between the different types of fractional branes. We
finally consider the IR behavior in several limits, where the dominant
effective dynamics is either confining, in a Coulomb phase or runaway, and
discuss the resolution of singularities in the dual geometric background.Comment: 38 pages + appendices, 15 figures; v2: refs added and typos correcte
Holographic renormalization and supersymmetry
Holographic renormalization is a systematic procedure for regulating
divergences in observables in asymptotically locally AdS spacetimes. For dual
boundary field theories which are supersymmetric it is natural to ask whether
this defines a supersymmetric renormalization scheme. Recent results in
localization have brought this question into sharp focus: rigid supersymmetry
on a curved boundary requires specific geometric structures, and general
arguments imply that BPS observables, such as the partition function, are
invariant under certain deformations of these structures. One can then ask if
the dual holographic observables are similarly invariant. We study this
question in minimal N = 2 gauged supergravity in four and five dimensions. In
four dimensions we show that holographic renormalization precisely reproduces
the expected field theory results. In five dimensions we find that no choice of
standard holographic counterterms is compatible with supersymmetry, which leads
us to introduce novel finite boundary terms. For a class of solutions
satisfying certain topological assumptions we provide some independent tests of
these new boundary terms, in particular showing that they reproduce the
expected VEVs of conserved charges.Comment: 70 pages; corrected typo
Localization of supersymmetric field theories on non-compact hyperbolic three-manifolds
We study supersymmetric gauge theories with an R-symmetry, defined on
non-compact, hyperbolic, Riemannian three-manifolds, focusing on the case of a
supersymmetry-preserving quotient of Euclidean AdS. We compute the exact
partition function in these theories, using the method of localization, thus
reducing the problem to the computation of one-loop determinants around a
supersymmetric locus. We evaluate the one-loop determinants employing three
different techniques: an index theorem, the method of pairing of eigenvalues,
and the heat kernel method. Along the way, we discuss aspects of supersymmetry
in manifolds with a conformal boundary, including supersymmetric actions and
boundary conditions.Comment: v3:79p, minor clarifications and references adde
Gravity duals of supersymmetric gauge theories on three-manifolds
We study gravity duals to a broad class of N=2 supersymmetric gauge theories
defined on a general class of three-manifold geometries. The gravity
backgrounds are based on Euclidean self-dual solutions to four-dimensional
gauged supergravity. As well as constructing new examples, we prove in general
that for solutions defined on the four-ball the gravitational free energy
depends only on the supersymmetric Killing vector, finding a simple closed
formula when the solution has U(1) x U(1) symmetry. Our result agrees with the
large N limit of the free energy of the dual gauge theory, computed using
localization. This constitutes an exact check of the gauge/gravity
correspondence for a very broad class of gauge theories with a large N limit,
defined on a general class of background three-manifold geometries.Comment: 74 pages, 2 figures; v2: minor change
Dynamique des populations et mosaïque forestière en hêtraie-sapinière naturelle préservée. une comparaison entre Vosges et Carpates
A comparison of population dynamics and forest architecture has been carried in two
well preserved beech-fir forests of Europe, in the Carpates and in the Vosges. The two
reserves present marked differences in climate, soils and local environment. We show that
beech dominates all the strata. In a situation of valley bottom (Carpates), its shady canopy
explains growth patterns of understorey. Beech and fir present alternating phases of suppression
and re-growth. Seedlings and saplings grow preferentially at the edges of adult canopies
and in gaps. In the Vosges, slope induces imbricated crowns, and lateral light inputs are
higher than in the Carpates. However regeneration is less dense because of less favourable
soils and climate, and located preferentially in the neighbourhood of gaps. Both forests
present a fine-grained architecture of eco-units, which increase resistance to disturbancesUne recherche comparative de sylvigénèse en hêtraie-sapinière a été entreprise dans deux réserves forestières intégrales, présentant des différences écologiques marquées dans les Hautes Vosges et les Carpates orientales. Les
données recueillies concernent la structure des populations de ligneux (hêtre, sapin, épicéa, érable sycomore) et l'organisation architecturale des mosaiques forestières, par deux profils architecturaux, qui illustrent un aspect des situations sylvigénétiques rencontrées dans ces forêts de
montagnes. Les principaux résultats démontrent que le hêtre domine les strates des deux forêts. En situation de fond de vallon (Carpates), l'ombrage qui résulte d'une canopée dense impose aux arbustes dominés (jeunes hêtres, mais surtout sapins) une croissance en palier parfois très longue,
qui explique les situations préférentielles des semis en bordure des éco-unités matures ou dans les trouées. En situation de pente (Vosges), l'architecture en pile d'assiette des dominants, qui résulte de l'importance des apports lumineux latéraux, raccourcit cette attente. Mais les
conditions plus rudes rencontrées dans cette réserve diminuent les densités à tous les étages. L'architecture des deux réserves montre une mosaïque fine d'éco-unités à différentes hauteurs, composées de plusieurs espèces ligneuses atteignant parfois des dimensions impressionnantes.
L'ensemble est très stable, en dépit des aléas climatiques
Operator Counting for N=2 Chern-Simons Gauge Theories with Chiral-like Matter Fields
The localization formula of Chern-Simons quiver gauge theory on nicely
reproduces the geometric data such as volume of Sasaki-Einstein manifolds in
the large- limit, at least for vector-like models. The validity of
chiral-like models is not established yet, due to technical problems in both
analytic and numerical approaches. Recently Gulotta, Herzog and Pufu suggested
that the counting of chiral operators can be used to find the eigenvalue
distribution of quiver matrix models. In this paper we apply this method to
some vector-like or chiral-like quiver theories, including the triangular
quivers with generic Chern-Simons levels which are dual to in-homogeneous
Sasaki-Einstein manifolds . The result is consistent
with AdS/CFT and the volume formula. We discuss the implication of our
analysis.Comment: 23 pages; v2. revised version; v3. corrected typos and clarified
argument
A topologically twisted index for three-dimensional supersymmetric theories
We provide a general formula for the partition function of three-dimensional (formula presented) gauge theories placed on S2
7S1 with a topological twist along S2, which can be interpreted as an index for chiral states of the theories immersed in background magnetic fields. The result is expressed as a sum over magnetic fluxes of the residues of a meromorphic form which is a function of the scalar zero-modes. The partition function depends on a collection of background magnetic fluxes and fugacities for the global symmetries. We illustrate our formula in many examples of 3d Yang-Mills-Chern-Simons theories with matter, including Aharony and Giveon-Kutasov dualities. Finally, our formula generalizes to \u3a9-backgrounds, as well as two-dimensional theories on S2 and four-dimensional theories on S2
7 T2. In particular this provides an alternative way to compute genus-zero A-model topological amplitudes and Gromov-Witten invariants
Constraints on chiral operators in N=2 SCFTs
Open Access, © The Authors. Article funded by SCOAP3.
This article is distributed under the terms of the Creative Commons
Attribution License (
CC-BY 4.0
), which permits any use, distribution and reproduction in
any medium, provided the original author(s) and source are credited
Higgs branch localization in three dimensions
We show that the supersymmetric partition function of three-dimensional N =2 R-symmetric Chern-Simons-matter theories on the squashed S 3 and on S 2
7 S 1 can be computed with the so-called Higgs branch localization method, alternative to the more standard Coulomb branch localization. For theories that could be completely Higgsed by Fayet-Iliopoulos terms, the path integral is dominated by BPS vortex strings sitting at two circles in the geometry. In this way, the partition function directly takes the form of a sum, over a finite number of points on the classical Coulomb branch, of a vortex-string times an antivortex-string partition functions. \ua9 2014 The Author(s)
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