2,342 research outputs found
AdS/CFT Correspondence and Type 0 String Theory
We review some applications of Type 0 string theory in the context of the
AdS/CFT correspondence.Comment: 6 pages, LaTeX + JHEP.cls, talk presented at the TMR conference
``Quantum aspects of gauge theories, supersymmetry and unification'', Paris,
September 1-7, 199
The gravity dual of supersymmetric gauge theories on a squashed
We present a new one-parameter family of supersymmetric solutions deforming
AdS_5. This is constructed as an asymptotically locally anti de Sitter (AlAdS)
solution of five-dimensional minimal gauged supergravity, with topology R x R^4
and a non-trivial graviphoton field, and can be uplifted to ten or eleven
dimensional supergravities. An analytic continuation of this solution yields
the gravity dual to a class of four-dimensional N=1 supersymmetric gauge
theories on a curved manifold with topology S^1 x S^3, comprising an SU(2) x
U(1)-symmetric squashed three-sphere, with a non-trivial background gauge field
coupling to the R-symmetry current. We compute the holographically renormalised
on-shell action and interpret it in terms of the Casimir energy of the dual
field theory. We also determine the holographic conserved charges of the
solution and discuss relations between them.Comment: 57 pages, 5 figures. v4: version published in JHE
Baryonic branches and resolutions of Ricci-flat Kahler cones
We consider deformations of N=1 superconformal field theories that are
AdS/CFT dual to Type IIB string theory on Sasaki-Einstein manifolds,
characterised by non-zero vacuum expectation values for certain baryonic
operators. Such baryonic branches are constructed from (partially) resolved,
asymptotically conical Ricci-flat Kahler manifolds, together with a choice of
point where the stack of D3-branes is placed. The complete solution then
describes a renormalisation group flow between two AdS fixed points. We discuss
the use of probe Euclidean D3-branes in these backgrounds as a means to compute
expectation values of baryonic operators. The Y^{p,q} theories are used as
illustrative examples throughout the paper. In particular, we present
supergravity solutions describing flows from the Y^{p,q} theories to various
different orbifold field theories in the infra-red, and successfully match this
to an explicit field theory analysis.Comment: 51 pages, v2: reference added and minor changes; v3: minor changes,
published versio
Toric Geometry, Sasaki-Einstein Manifolds and a New Infinite Class of AdS/CFT Duals
Recently an infinite family of explicit Sasaki-Einstein metrics Y^{p,q} on
S^2 x S^3 has been discovered, where p and q are two coprime positive integers,
with q<p. These give rise to a corresponding family of Calabi-Yau cones, which
moreover are toric. Aided by several recent results in toric geometry, we show
that these are Kahler quotients C^4//U(1), namely the vacua of gauged linear
sigma models with charges (p,p,-p+q,-p-q), thereby generalising the conifold,
which is p=1,q=0. We present the corresponding toric diagrams and show that
these may be embedded in the toric diagram for the orbifold C^3/Z_{p+1}xZ_{p+1}
for all q<p with fixed p. We hence find that the Y^{p,q} manifolds are AdS/CFT
dual to an infinite class of N=1 superconformal field theories arising as IR
fixed points of toric quiver gauge theories with gauge group SU(N)^{2p}. As a
non-trivial example, we show that Y^{2,1} is an explicit irregular
Sasaki-Einstein metric on the horizon of the complex cone over the first del
Pezzo surface. The dual quiver gauge theory has already been constructed for
this case and hence we can predict the exact central charge of this theory at
its IR fixed point using the AdS/CFT correspondence. The value we obtain is a
quadratic irrational number and, remarkably, agrees with a recent purely field
theoretic calculation using a-maximisation.Comment: 54 pages, 5 figures; minor changes; further minor changes, ref [8]
added - published version; eqns 1.3, 1.4 remove
Symmetry-breaking vacua and baryon condensates in AdS/CFT
We study the gravity duals of symmetry-breaking deformations of
superconformal field theories, AdS/CFT dual to Type IIB string theory on AdS_5
x Y where Y is a Sasaki-Einstein manifold. In these vacua both conformal
invariance and baryonic symmetries are spontaneously broken. We present a
detailed discussion of the supergravity moduli space, which involves flat form
fields on asymptotically conical Calabi-Yau manifolds, and match this to the
gauge theory vacuum moduli space. We discuss certain linearised fluctuations of
the moduli, identifying the Goldstone bosons associated with spontaneous
breaking of non-anomalous baryonic symmetries. The remaining moduli fields are
related to spontaneous breaking of anomalous baryonic symmetries. We also
elaborate on the proposal that computing condensates of baryon operators is
equivalent to computing the partition function of a non-compact Euclidean
D3-brane in the background supergravity solution, with fixed boundary
conditions at infinity.Comment: 121 pages; v2: references adde
The large N limit of quiver matrix models and Sasaki-Einstein manifolds
We study the matrix models that result from localization of the partition
functions of N=2 Chern-Simons-matter theories on the three-sphere. A large
class of such theories are conjectured to be holographically dual to M-theory
on Sasaki-Einstein seven-manifolds. We study the M-theory limit (large N and
fixed Chern-Simons levels) of these matrix models for various examples, and
show that in this limit the free energy reproduces the expected AdS/CFT result
of N^{3/2}/Vol(Y)^{1/2}, where Vol(Y) is the volume of the corresponding
Sasaki-Einstein metric. More generally we conjecture a relation between the
large N limit of the partition function, interpreted as a function of trial
R-charges, and the volumes of Sasakian metrics on links of Calabi-Yau four-fold
singularities. We verify this conjecture for a family of U(N)^2 Chern-Simons
quivers based on M2 branes at hypersurface singularities, and for a U(N)^3
theory based on M2 branes at a toric singularity.Comment: 38 pages, 4 figures; v2: minor changes, typos and factor of 2 in eq.
(5.19) fixed, references and 2 figures added; v3: new section 4.5 added; v4:
more typos fixed, range of validity of (4.19) clarifie
The gravity dual of supersymmetric gauge theories on a two-parameter deformed three-sphere
We present rigid supersymmetric backgrounds for three-dimensional N=2
supersymmetric gauge theories, comprising a two-parameter U(1)xU(1)-invariant
deformed three-sphere, and their gravity duals. These are described by
supersymmetric solutions of four-dimensional N=2 gauged supergravity with a
self-dual metric on the ball and different instantons for the graviphoton
field. We find two types of solutions, distinguished by their holographic free
energies. In one type the holographic free energy is constant, whereas in
another type it depends in a simple way on the parameters and is generically
complex. This leads to a conjecture for the localized partition function of a
class of N=2 supersymmetric gauge theories on these backgrounds.Comment: 27 pages, 1 figure; v2: typos fixed, minor changes, one reference
adde
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