35 research outputs found
Supersymmetric black holes and attractors in gauged supergravity with hypermultiplets
We consider four-dimensional supergravity coupled to vector- and
hypermultiplets, where abelian isometries of the quaternionic K\"ahler
hypermultiplet scalar manifold are gauged. Using the recipe given by Meessen
and Ort\'{\i}n in arXiv:1204.0493, we analytically construct a supersymmetric
black hole solution for the case of just one vector multiplet with prepotential
, and the universal hypermultiplet. This solution has
a running dilaton, and it interpolates between
at the horizon and a hyperscaling-violating type geometry at infinity,
conformal to . It carries two magnetic charges
that are completely fixed in terms of the parameters that appear in the Killing
vector used for the gauging. In the second part of the paper, we extend the
work of Bellucci et al. on black hole attractors in gauged supergravity to the
case where also hypermultiplets are present. The attractors are shown to be
governed by an effective potential , which is extremized on the
horizon by all the scalar fields of the theory. Moreover, the entropy is given
by the critical value of . In the limit of vanishing scalar
potential, reduces (up to a prefactor) to the usual black hole
potential.Comment: 21 pages, uses jheppub.sty. v2: Refs. adde
BPS black holes in a non-homogeneous deformation of the stu model of , gauged supergravity
We consider a deformation of the well-known stu model of ,
supergravity, characterized by a non-homogeneous special K\"{a}hler manifold,
and by the smallest electric-magnetic duality Lie algebra consistent with its
upliftability to five dimensions. We explicitly solve the BPS attractor
equations and construct static supersymmetric black holes with radial symmetry,
in the context of dyonic Fayet-Iliopoulos gauging, focussing on
axion-free solutions. Due to non-homogeneity of the scalar manifold, the model
evades the analysis recently given in the literature. The relevant physical
properties of the resulting black hole solution are discussed.Comment: 26 pages, uses jheppub.st
AdS solutions with exceptional supersymmetry
Among the possible superalgebras that contain the AdS isometries, two
interesting possibilities are the exceptional and . Their
R-symmetry is respectively SO(7) and , and the amount of supersymmetry
and . We find that there exist two (locally) unique
solutions in type IIA supergravity that realize these superalgebras, and we
provide their analytic expressions. In both cases, the internal space is
obtained by a round six-sphere fibred over an interval, with an O8-plane at one
end. The R-symmetry is the symmetry group of the sphere; in the case, it
is broken to by fluxes. We also find several numerical
solutions with flavor symmetry, with various localized sources, including
O2-planes and O8-planes.Comment: 30 pages, 4 figures; v3: revised appendix, minor correction
Towards AdS Distances in String Theory
The AdS Distance Conjecture proposes to assign a notion of distance between
AdS vacua in quantum gravity. We perform some initial developments of this
idea. We first propose more sharply how to define a metric on conformal
variations of AdS through the action. This metric is negative, making the
distance ill-defined, a property relating to the famous conformal factor
problem of quantum gravity. However, in string theory, variations of the AdS
conformal factor are accompanied by variations of the internal dimensions and
of the background flux. We propose an , which accounts
for all of these variations simultaneously. Accounting for the variations of
the overall volume of the internal dimensions can flip the sign of the action
metric making it positive. This positivity is related to the absence of scale
separation between the internal and external dimensions: the negative external
conformal contribution must be sub-dominant to the positive internal
contribution. We then focus specifically on the families of solutions of
eleven-dimensional supergravity on AdS and AdS.
For these, there is only a single further additional contribution to the action
metric coming from variations of the Freund-Rubin flux. This contribution is
subtle to implement, and the unique prescription we find requires singling out
the radial direction of AdS as special. Adding the flux contribution yields an
overall total action metric which becomes positive for both the AdS and
AdS families of solutions. The final result is therefore a procedure which
yields a well-defined distance for these families of solutions.Comment: 30 page
Black string first order flow in N = 2, d = 5 abelian gauged supergravity
We derive both BPS and non-BPS first-order flow equations for magnetically
charged black strings in five-dimensional N=2 abelian gauged supergravity,
using the Hamilton-Jacobi formalism. This is first done for the coupling to
vector multiplets only and U(1) Fayet-Iliopoulos (FI) gauging, and then
generalized to the case where also hypermultiplets are present, and abelian
symmetries of the quaternionic hyperscalar target space are gauged. We then use
these results to derive the attractor equations for near-horizon geometries of
extremal black strings, and solve them explicitely for the case where the
constants appearing in the Chern-Simons term of the supergravity action satisfy
an adjoint identity. This allows to compute in generality the central charge of
the two-dimensional conformal field theory that describes the black strings in
the infrared, in terms of the magnetic charges, the CY intersection numbers and
the FI constants. Finally, we extend the r-map to gauged supergravity and use
it to relate our flow equations to those in four dimensions.Comment: 21 pages, uses jheppub.sty. v2: Minor errors corrected, refs. added.
v3: Minor error corrected in app. B, small discussion of string theory
realization added in final remark
AdS near-horizons, defects and string dualities
We construct a new family of solutions to
Type IIB supergravity arising as near-horizon geometries of D1-F1-D3-D5-NS5-D7
brane intersections preserving 4 supersymmetries. We show that a subclass of
these solutions asymptotes locally to the solution to Type IIB supergravity holographically dual to the five
dimensional Sp(N) fixed point theory. This suggests that these solutions can be
interpreted as D1-F1-D3 line defects within this CFT. Switching off the
D7-branes, we act with to construct a second family
of solutions that can be related to an class
of M-theory backgrounds describing surface defects within the six dimensional
(1,0) SCFT dual to . Finally, using
non-Abelian T-duality we construct new classes of solutions to Type IIA supergravity with 4 supercharges and elaborate on
their M-theory origin.Comment: 24 page