104 research outputs found
Static supersymmetric black holes in AdS_4 with spherical symmetry
We elaborate further on the static supersymmetric AdS_4 black holes found in
arXiv:0911.4926, investigating thoroughly the BPS constraints for spherical
symmetry in N = 2 gauged supergravity in the presence of Fayet-Iliopoulos
terms. We find Killing spinors that preserve two of the original eight
supercharges and investigate the conditions for genuine black holes free of
naked singularities. The existence of a horizon is intimately related with the
requirement that the scalars are not constant, but given in terms of harmonic
functions in analogy to the attractor flow in ungauged supergravity. The black
hole charges depend on the choice of the electromagnetic gauging, with only
magnetic charges for purely electric gaugings. Finally we show how these black
holes can be embedded in N = 8 supergravity and thus in M-theory.Comment: 28 pages; v2 minor change
6d-5d-4d reduction of BPS attractors in flat gauged supergravities
Via a series of Kaluza-Klein (KK) and Scherk-Schwarz (SS) compactifications
we relate BPS attractors and their complete (in general non-BPS) flows to a
Minkowski vacuum in gauged supergravities with vanishing scalar potential in 4,
5, and 6 dimensions. This way we can look at a class of extremal non-BPS black
holes and strings from IIB string theory viewpoint, keeping 4 supercharges on
the horizon. Our results imply the existence of a dual 2d N = (0,2)
superconformal field theory (SCFT) that originates from a parent N=(4,4) theory
living on a D1-D5 system.
This is achieved starting from the BPS black string in 6d with an AdS_3xS^3
attractor and taking two different routes to arrive at a 1/2 BPS AdS_2xS^2
attractor of a non-BPS black hole in 4d N=2 flat gauged supergravity. The two
inequivalent routes interchange the order of KK reduction on AdS_3 and SS
reduction on S^3. We also find the commutator between the two operations after
performing a duality transformation: on the level of the theory the result is
the exchange of electric with magnetic gaugings; on the level of the solution
we find a flip of the quartic invariant I_4 to -I_4.Comment: 20 pages, 2 flow charts; v2 improved discussion and added referenc
Lessons from the Vacuum Structure of 4d N=2 Supergravity
This PhD thesis is devoted to the study of supersymmetry preserving
background solutions of N=2 supergravity in 4 dimensions. The main contents are
divided into three major parts, briefly summarized as follows. Part I deals
with analysis of maximally supersymmetric configurations. Part II discusses BPS
black holes with Minkowski and anti-de Sitter (AdS) asymptotics. The main
topics in part III are superalgebras, BPS bounds and conserved charges for
asymptotically flat or AdS spacetimes. Most of the chapters are based on
previously published results with the exception of chapter 10 in part III,
which is genuinely new and discusses the superalgebras of black hole
configurations and their near-horizon geometries. A no-go theorem for static
BPS black holes in AdS is proven in theories without hypermultiplets and the
analogous situation in 5d is briefly explained.Comment: 209 pages; PhD thesis, defended 1 June 2012, advisor Stefan Vandoren;
v2 minor correction
Ungauging black holes and hidden supercharges
We embed the general solution for non-BPS extremal asymptotically flat static
and under-rotating black holes in abelian gauged D=4 N=2 supergravity, in the
limit where the scalar potential vanishes but the gauging does not. Using this
result, we show explicitly that some supersymmetries are preserved in the near
horizon region of all the asymptotically flat solutions above, in the gauged
theory. This reveals a deep relation between microscopic entropy counting of
extremal black holes in Minkowski and BPS black holes in AdS. Finally, we
discuss the relevance of this construction to the structure of asymptotically
AdS4 black holes, as well as the possibility of including hypermultiplets.Comment: 33 pages, 1 figure, v2: Corrections in section 5, comments added,
references update
Phase transitions of magnetic AdS4 black holes with scalar hair
We determine the thermodynamic properties of a class of spherically symmetric
and static black holes in AdS4 with magnetic charges and scalar hair. These
black holes are solutions in 4d N=2 gauged supergravity that can arise from
eleven-dimensional supergravity compactified on S^7. At zero temperature, they
preserve supersymmetry and hence are stable. At non-zero temperatures, we
explore in detail the canonical ensemble and stability of solutions and find a
first order phase transition between small and large hairy black holes. The
transition emerges as a liquid-gas phase transition in the dual
three-dimensional field theory on R x S^2 with magnetic flux through S^2.Comment: 5 pages, v2: misprints corrected and references added, published
versio
An extremization principle for the entropy of rotating BPS black holes in AdS
We show that the Bekenstein-Hawking entropy of a class of BPS electrically
charged rotating black holes in AdS can be obtained by a simple
extremization principle. We expect that this extremization corresponds to the
attractor mechanism for BPS rotating black holes in five-dimensional gauged
supergravity, which is still unknown. The expression to be extremized has a
suggestive resemblance to anomaly polynomials and the supersymmetric Casimir
energy recently studied for super Yang-Mills.Comment: 27 pages; v2: refs added; v3: ref adde
Wilson lines for AdS_5 black strings
We describe a simple method of extending AdS_5 black string solutions of 5d
gauged supergravity in a supersymmetric way by addition of Wilson lines along a
circular direction in space. When this direction is chosen along the string,
and due to the specific form of 5d supergravity that features Chern-Simons
terms, the existence of magnetic charges automatically generates conserved
electric charges in a 5d analogue of the Witten effect. Therefore we find a
rather generic, model-independent way of adding electric charges to already
existing solutions with no backreaction from the geometry or breaking of any
symmetry. We use this method to explicitly write down more general versions of
the Benini-Bobev black strings and comment on the implications for the dual
field theory and the similarities with generalizations of the Cacciatori-Klemm
black holes in AdS_4.Comment: 13 pages; v2 improved discussion, added reference
Spindle black holes in AdSSE
We construct new classes of supersymmetric AdS solutions
of 4d gauged supergravity in presence of charged hypermultiplet scalars, with
the complex weighted projective space known as a spindle. These
solutions can be viewed as near-horizon geometries of asymptotically Anti
de-Sitter (AdS) black holes with magnetic fluxes that admit embedding in
11d on Sasaki-Einstein (SE) manifolds, which renders them of holographic
interest. We show that in each case the Bekenstein-Hawking entropy follows from
the procedure of gluing two gravitational blocks, ultimately determined by
SE data. This allows us to establish the general form of the gravitational
blocks in gauged 4d supergravity with charged scalars and
massive vectors. Holographically, our results provide a large N answer for the
spindle index with anti-twist and additional mesonic or baryonic fluxes of a
number of Chern-Simons-matter theories.Comment: 40 pages, 2 figures, 1 Mathematica fil
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