143 research outputs found
AdS4 black holes from M-theory
We consider the BPS conditions of eleven dimensional supergravity, restricted
to an appropriate ansatz for black holes in four non-compact directions.
Assuming the internal directions to be described by a circle fibration over a
K\"ahler manifold and considering the case where the complex structure moduli
are frozen, we recast the resulting flow equations in terms of polyforms on
this manifold. The result is a set of equations that are in direct
correspondence with those of gauged supergravity models in four dimensions
consistent with our simplifying assumptions. In view of this correspondence
even for internal manifolds that do not correspond to known consistent
truncations, we comment on the possibility of obtaining gauged supergravities
from reductions on K\"ahler manifolds.Comment: 32 pages, v2: references addes, typos correcte
Parameter spaces of massive IIA solutions
We find a new class of N=2 massive IIA solutions whose internal spaces are
S^2 fibrations over S^2 x S^2. These solutions appear naturally as massive
deformations of the type IIA reduction of Sasaki-Einstein manifolds in
M-theory, including Q^{1,1,1} and Y^{p,k}, and play a role in the AdS4/CFT3
correspondence. We use this example to initiate a systematic study of the
parameter space of massive solutions with fluxes. We define and study the
natural parameter space of the solutions, which is a certain dense subset of
R^3, whose boundaries correspond to orbifold or conifold singularities. On a
codimension-one subset of the parameter space, where the Romans mass vanishes,
it is possible to perform a lift to M-theory; extending earlier work, we
produce a family A^{p,q,r} of Sasaki-Einstein manifolds with cohomogeneity one
and SU(2) x SU(2) x U(1) isometry. We also propose a Chern-Simons theory
describing the duals of the massless and massive solutions.Comment: 35 pages, 5 figures; comments and references adde
Holography for (1,0) theories in six dimensions
M-theory and string theory predict the existence of many six-dimensional
SCFTs. In particular, type IIA brane constructions involving NS5-, D6- and
D8-branes conjecturally give rise to a very large class of N=(1,0) CFTs in six
dimensions. We point out that these theories sit at the end of RG flows which
start from six-dimensional theories which admit an M-theory construction as a
M5 stack transverse to . The flows are triggered by Higgs
branch expectation values and correspond to D6's opening up into transverse
D8-branes via a Nahm pole. We find a precise correspondence between these CFT's
and the AdS vacua found in a recent classification in type II theories.
Such vacua involve massive IIA regions, and the internal manifold is
topologically . They are characterized by fluxes for the NS three-form and
RR two-form, which can be thought of as the near-horizon version of the NS5's
and D6's in the brane picture; the D8's, on the other hand, are still present
in the AdS solution, in the form of an arbitrary number of concentric
shells wrapping round 's.Comment: 32 pages, 11 figures. v2: extra citations, corrections to figures 2
and 1
Pure spinor equations to lift gauged supergravity
We rewrite the equations for ten-dimensional supersymmetry in a way formally
identical to a necessary and sufficient G-structure system in N=2 gauged
supergravity, where all four-dimensional quantities are replaced by
combinations of pure spinors and fluxes in the internal space. This provides a
way to look for lifts of BPS solutions without having to reduce or even rewrite
the ten-dimensional action. In particular this avoids the problem of consistent
truncation, and the introduction of unphysical gravitino multiplets.Comment: 61 page
Minimal flux Minkowski classification
We classify Minkowski solutions in type IIA supergravity, with N=2
supersymmetry and an SU(2) R-symmetry of a certain type. Many subcases can be
reduced to relatively simple PDEs, among which we recover various intersecting
brane systems, and AdS solutions, , and in particular the recently
found general massive AdS solutions. Imposing compactness of the internal
six-manifold we obtain promising solutions with localized D-branes and
O-planes.Comment: v2: Result slightly strengthened, typos corrected. v3: Published
Versio
Universal consistent truncation for 6d/7d gauge/gravity duals
Recently, AdS_7 solutions of IIA supergravity have been classified; there are
infinitely many of them, whose expression is known analytically, and with
internal space of S^3 topology. Their field theory duals are six-dimensional
(1,0) SCFT's. In this paper we show that for each of these AdS_7 solutions
there exists a consistent truncation from massive IIA supergravity to minimal
gauged supergravity in seven dimensions. This theory has an SU(2) gauge group,
and a single scalar, whose value is related to a certain distortion of the
internal S^3. This explains the universality observed in recent work on AdS_5
and AdS_4 solutions dual to compactifications of the (1,0) SCFT_6's. Thanks to
previous work on the minimal gauged supergravity, the truncation also implies
the existence of holographic RG-flows connecting those solutions to the AdS_7
vacuum, as well as new classes of IIA AdS_3 solutions.Comment: 23 pages; v2: references added, minor changes, additions and
correction
Timelike structures of ten-dimensional supersymmetry
In several contexts, supersymmetry can be reformulated in terms of
calibrations, namely forms whose integrals measure minimal energies. It has
been conjectured that this should be possible in general. For type II
supergravity, we present a new system of equations which realizes this
expectation. Besides the customary D-brane calibrations, it also includes
NS5-brane and KK5-monopole calibrations. It is equivalent to supersymmetry
under the assumption that the Killing vector associated to supersymmetry is
timelike. No assumption is made on a factorization of spacetime. We also obtain
a version of the system which is manifestly S-invariant and we present an
application to near-horizon backgrounds. Using calibration, a definition of
central charges in purely gravitational terms is given.Comment: 61 pages; v2: matches published version, comments adde
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